text stringlengths 454 608k | url stringlengths 17 896 | dump stringclasses 91 values | source stringclasses 1 value | word_count int64 101 114k | flesch_reading_ease float64 50 104 |
|---|---|---|---|---|---|
Schemer's Guide to PHP
PHP, a recursive acronym for "PHP: Hypertext Preprocessor", is an open-source scripting language that is especially suited for Web development because it is easily embedded into HTML. This document should provide enough information to get started writing PHP programs, but you may need to consult the online PHP manual (available at) to find out about primitive procedures in PHP that may be useful for your projects.
What distinguishes PHP from other "Internet" languages you may have heard of, like JavaScript, is that the PHP code is run ("executed") on the server. We can embed PHP directly in HTML pages by using a special sequence of characters — <? to indicate the start PHP code, and ?> to end. PHP is not built into HTML, but is an extension supported by many web servers, including Apache, the UVa server you will be using.
Element ::= <? PHPCode ?>Here is an example web page that incorporates PHP:When a browser requests the page above, the HTML will be displayed normally, but the PHP code will be evaluated on the server. The output of evaluating the PHP code is included in the resulting web page.When a browser requests the page above, the HTML will be displayed normally, but the PHP code will be evaluated on the server. The output of evaluating the PHP code is included in the resulting web page.
<html>
<head>
<title>A PHP Web Page</title>
</head>
<body>
<p>This is HTML</p>
<?
print "This is PHP.<br>";
print "This is <em>still</em> PHP.<br>";
?>
<B>Now we're back to HTML.</B>
</body>
</html>
Here is the result: sample.php3. Note: It is important to name the file something ending in .php3. Otherwise, the server will not evaluate the PHP code.
Note that the HTML formatting in the PHP code still works. Everything we print in PHP code embedded in a web page end up in the HTML that is then displayed by the browser. Before reading further, try setting up a web page that uses PHP in your home directory.
Programming in PHP
PHP is a universal programming language — this means every process we could describe using in Scheme, we can also describe in PHP (we'll cover more formally what it means to be a universal programming language in class April 15th). The syntax of PHP is very different from Scheme, but many of the evaluation rules should be familiar.
The PHP code in a web page is a sequence of instructions separated by semi-colons (;):PHPCode ::= InstructionsPHP has many different kinds of Instructions. The three you will use most are assignment, applications and function definitions:
Instructions ::= Instruction ; Instructions
Instructions ::=
Instruction ::= AssignmentInstruction
Instruction ::= ApplicationInstruction
Instruction ::= FunctionDefinition
AssignmentScheme is designed for a functional programming style. This means most of a Scheme program is applying and defining functions (and procedures). PHP is designed for an imperative programming style. This means most of a PHP program is assignments. In Scheme, we use set! to do assignment. In PHP, we use the = sign to mean assignment (to do equality comparisons, PHP uses ==):AssignmentInstruction ::= Variable = ExpressionIn PHP, all variables must begin with the dollar sign ($).
To evaluate an AssignmentInstruction, PHP evaluates the Expression and places the value in the place named Variable. (Just like the Scheme evaluation rule for set!). The only difference is if there is not already a place named Variable, PHP will create a new place as a result of the assignment instruction. Hence, the PHP instruction $x = 1 will act like (define x 1) if there is no place already named x, and like (set! x 1) if there is already a place named x.
An expression in PHP is similar to an expression in Scheme — it is a code fragment that evaluates to a value. In PHP, expressions use infix notation. The operator is placed between the operands (except for function calls, described below). PHP supports most of the standard arithmetic operators. Here are some examples:
Note the PHP uses 1 to mean true. PHP considers the empty string and 0 to be false, and (almost) everything else true.Note the PHP uses 1 to mean true. PHP considers the empty string and 0 to be false, and (almost) everything else true.
Applying FunctionsIn PHP, we apply a function to operands by following the name of the function with a comma-separated list of arguments surrounded by parentheses:ApplicationInstruction ::= Name( Arguments )This is equivalent to (Name Arguments) in Scheme (except there are no commas between the arguments in Scheme).
Arguments ::=
Arguments ::= MoreArguments
MoreArguments Argument ,MoreArguments
MoreArguments ::= Argument
Argument ::= Expression
PHP has many primitive functions. The Function Reference section of the PHP manual has subsections from I to CVIII (108) describing a riduculous number of functions provided by PHP. Luckily, you will only need to use a few of them. The last section of this document describes some of the more useful provided functions.
Defining FunctionsDefining a procedure in PHP is similar to in Scheme, except:
We define a function using:We define a function using:
- instead of using lambda, you list the parameters after the function name
- instead of just evaluating to a value, you must use return to explicitly evaluate to a resultFunctionDefinition ::= function ( Parameters ) { Instructions }For example,
Parameters ::=
Parameters ::= MoreParameters
MoreParameters Parameter ,MoreParameters
MoreParameters ::= Parameter Parameter ::= Variable
PHP also provides a function create_function for making procedures the way you would in Scheme using lambda:PHP also provides a function create_function for making procedures the way you would in Scheme using lambda:Expression ::= create_function (String1, String2)The parameters are passed as the first string (as a comma-separated list), and the body is passed as the second string. For example, (lambda (a b) (+ a b)) would be create_function ('$a $b', 'return $a + $b'). Here's an example:$adder = create_function ('$a,$b', 'return ($a + $b);');PHP does not evaluate applications the same way as Scheme, however. In particular, it does not create a new frame to with places for the parameters.
print "Adding: " . $adder (2, 2) . "<br>";
Adding: 4
Control InstructionsPHP also provides several instructions similar to Scheme special forms. Two useful ones are if and while which are described below. PHP also support switch (similar to Scheme's case), for (similar to Java's for from 1 Feb's notes).
IfThe if instruction is similar to Scheme's if special form:Instruction ::= if (Expression) { Instructions }is equivalent to (if Expression (begin Instructions)).
PHP also supports alternative clauses but uses else to distinguish them:Instruction ::= if (Expression) { Instructions1 } else { Instructions2 }is equivalent to (if Expression (begin Instructions1) (begin Instructions2)).
WhileThe while instruction repeats a sequence of instructions as long as the test expression is true:Instruction ::= while (Expression) { Instructions }Here is an example that will print out the first 10 Fibonacci numbers:
$i = 1; $a = 1; $b = 1; while ($i <= 10) { print "Fibonacci $i = $b<br>"; $next = $a + $b; $a = $b; $b = $next; $i = $i + 1; } ;
TypesLike Scheme, PHP has latent (invisible) types that are checked dynamically. The three types you will find most useful are numbers, strings and arrays.
NumbersPHP treats numbers like Scheme, except it does not do exact arithmetic. Instead of using fractions, everything is treated as either an integer or a floating point number. Here are some examples:
StringsPHP treats strings like Scheme: they need quotation marks. You can use single quotes (') or double quote ("). However, there is a very important difference — when you use double quotes variables in the string are evaluated, but when you use single quotes they are not.
Here are some examples:
You can concatenate (run together) two strings by using the dot (.). So, alternatively, we could have used:You can concatenate (run together) two strings by using the dot (.). So, alternatively, we could have used:print "See " . $name . " run";If you want a literal quote to appear in a string you print, use \":
print "My name is \"Spot\".";
ArraysPHP doesn't have lists, but it has arrays which are the next best thing. An array is actually a list of (key, value) pairs. A PHP array is similar to the frame's we implemented for the Mini-Scheme evaluator — there is a way to add a new (key, value) pair to a frame, and there is a way to lookup the value associated with a key. For our Mini-Scheme frames, the key was always a symbol, and the value could be any Mini-Scheme value. In PHP, the key can be either a non-negative integer or a string; the value can be any PHP value.
We can set the value associated with a key using: using:SetInstruction ::= Expression [ Expression ] = ExpressionWe get the value associated with a key using:FetchExpression ::= Expression [ Expression ]The first expression in a fetch expression must evaluate to an array.
Here are some examples:$yellow['red'] = 255;Another way to create an array is to use the array function. For example, this code is equivalent to the three assignments above:
$yellow['green'] = 255;
$yellow['blue'] = 0;
print '(' . $yellow['red'] . ', ' . $yellow['green'] . ', ' . $yellow['blue'] . ')';
(255, 255, 0)$yellow = array ('red' => 255, 'green' => 255, 'blue' => 0);If we leave out the keys, PHP will create an array using the integers (starting from 0) as the keys:$presidents = array ("George Washington", "John Adams", "Thomas Jefferson", "James Madison", "James Monroe");(Note that without anything else, the web page this generates is:
print $presidents[0];
George Washingtonprint $presidents[2];
Thomas Jeffersonprint $presidents[5];
James Monroeprint $presidents[42];
There is no value matching key 6. PHP does not report an error, it just evaluates to the empty string.There is no value matching key 6. PHP does not report an error, it just evaluates to the empty string.
$presidents[42] = "George Walker Bush";
print $presidents[42];
George Walker BushThere are no new lines or spaces between the print commands.There are no new lines or spaces between the print commands.
George WashingtonThomas JeffersonGeorge Walker Bush
Of course, we can put arrays in arrays, just like we can make lists of lists in Scheme. Here is a more complicated example:This produces:This produces:$presidents = array ( 1 => array ('name' => "George Washington", 'bill' => "$1"), array ('name' => "John Adams", 'college' => "Harvard" ), array ('name' => "Thomas Jefferson", 'bill' => "$2", 'college' => "William and Mary" ), array ('name' => "James Madison", 'college' => "Princeton" ), 43 => array ('name' => "George Bush", 'college' => "Yale" )); foreach ($presidents as $president) { print "Name: " . $president['name'] . "<br>"; print "Bill: " . $president['bill'] . "<br>"; print "College: " . $president['college'] . "<br><p>"; }We use 1 => for the first element of the array, so the keys start counting from 1 instead of 0.We use 1 => for the first element of the array, so the keys start counting from 1 instead of 0.
Name: George Washington
Bill: $1
College:
Name: John Adams
Bill:
College: Harvard
Name: Thomas Jefferson
Bill: $2
College: William and Mary
Name: James Madison
Bill:
College: Princeton
Name: George Bush
Bill:
College: Yale
We use the foreach construct to do something to all the elements in the array, similar to the Scheme map procedure:ForEachInstruction ::= foreach (Array as Variable ) { Instructions }is the same as:(map (lambda (Variable) Instructions) Array)
Getting Input
If you talk to almost any web developer, they will tell you that the best thing about PHP is that it transparently parses HTTP_POST data. Then they will do cartwheels out of sheer glee. This is just fancy jargon for "The computer acts smart (for once)."
For every form element with a name="Name" parameter in your HTML form, PHP will create a variable with the name $Name and assign it whatever data the user entered.
If the user entered no data, the variable will be assigned an empty string. You can then reference those variables like any other PHP variable. For example, you could put them into a SQL statement.
For the example form:PHP will assign the variable $FirstName to the text the visitor entered in the input named FirstName. We can use that just like any other PHP variable. For example, here is the file form.process.php3 that processor the form above:PHP will assign the variable $FirstName to the text the visitor entered in the input named FirstName. We can use that just like any other PHP variable. For example, here is the file form.process.php3 that processor the form above:
<FORM METHOD="POST" ACTION="form.process.php3">
First name: <INPUT TYPE="TEXT" NAME="FirstName"><BR>
Last name: <INPUT TYPE="TEXT" NAME="LastName"><BR>
<TEXTAREA ROWS="3" NAME="UserComments"></TEXTAREA><BR>
<INPUT TYPE="SUBMIT"><INPUT TYPE="RESET">
</FORM>
<?
print "Thank you for your information!";
print "<BR>";
print "Name: " . $FirstName . " " . $LastName . "<BR>";
print "Comments: " . $UserComments;
?>
You can try it here:
Is that cool or what? In your situation, you'll often be using the user input to create a SQL command to insert, select or update from your database.
Using SQLBefore reading this section, read the SQL Guide.
PHP provides procedures for interacting with a database using SQL. You can call these procedures like any other PHP procedure. The PHP evaluator will send the appropriate commands to the SQL database.
Before using any SQL commands, you must connect to the database server and open a database. Do this using mysql_connect (hostname, username, password). The hostname for the ITC database is dbm1.itc.virginia.edu; the username and password are those you used to create your database account. Then, use mysql_select_db (name) to select the database. The name of the database should name the name of the database you created.
Here is the set up code from the example:Note how we use or exit("...") after the calls to mysql_connect and mysql_select_db to fail gracefully if there is an error.Note how we use or exit("...") after the calls to mysql_connect and mysql_select_db to fail gracefully if there is an error.$hostName = "dbm1.itc.virginia.edu"; $userName = "dee2b"; $password = "quist"; $dbName = "dee2b_presidents"; mysql_connect($hostName, $userName, $password) or exit("Unable to connect to host $hostName"); mysql_select_db($dbName) or exit("Database $dbName does not exist on $hostName");
Next, you will probably want to send a SQL command to the database. This is done using mysql_query (SQL Command). The SQL Command is just a string that is a SQL command. For example,The command can be any PHP string, so long as it is a valid SQL command.The command can be any PHP string, so long as it is a valid SQL command.$result = mysql_query("SELECT lastname, firstname FROM presidents " . "WHERE college='William and Mary' ORDER BY lastname");
The call to mysql_query returns a resource that can be used to get information about the SQL result. In the example, we assigned the result to $result.
There are several PHP procedures for getting information about the result of a SQL command. All of these take the value returned by a call to mysql_query as their first parameter.
Here are some examples:At the end of your PHP program, you should close the database using mysql_close ().At the end of your PHP program, you should close the database using mysql_close ().// Determine the number of rows $numrows = mysql_num_rows($result); $numcols = mysql_num_fields($result); // print the results print "<table border=0 cellpadding=5>"; print "<tr>"; for ($k = 0; $k < $numcols; $k = $k + 1) { print "<th>" . mysql_field_name ($result, $k) . "</th>"; } print "</tr>"; for ($i = 0; $i < $numrows; $i++) // $i++ is short for $i = $i + 1 { for ($j = 0; $j < $numcols; $j++) { print "<td>" . mysql_result ($result, $i, $j) . "</td>"; } print "</tr>"; } print "</table>";
Primitive ProceduresPHP has thousands of built-in functions (primitives). And even better PHP also has one of the best online sources of help in the world. The manual provides details on every single function built into PHP, we will only describe a few of them here.
For more information
The grammar we provide does not define the entire language supported by PHP. There are strings that are valid PHP programs that are not in the language defined by our grammar.
See the PHP Manual:. | http://www.cs.virginia.edu/cs200/guides/php-guide.html | CC-MAIN-2017-47 | refinedweb | 2,648 | 53.81 |
Donn Cave <donn at u.washington.edu> wrote in message news:<donn-65345D.10415616062004 at nntp1.u.washington.edu>... > In article <40d07ac6 at rutgers.edu>, > "George Sakkis" <gsakkis at rutgers.edu> wrote: > > > I find the string representation behaviour of builtin containers > > (tuples,lists,dicts) unintuitive in that they don't call recursively str() > > on their contents (e.g. as in Java) > > Please find last week's answers to this question at > > > If you're still interested in further discussion of this > point, you could present an account of Java's approach > for the edification of those of us who don't know. All Java classes include a toString() method (defined in the root class java.lang.Object), which returns the string representation of that object. Each of the standard collection classes in java.util defines its toString() method to recursively call toString() on its elements. For example, the program import java.util.*; public class Foo { public static void main(String[] args) { List lst = new ArrayList(); lst.add("a"); lst.add("b"); lst.add("c"); System.out.println(lst); } } prints "[a, b, c]". (Btw, this reminds me of something I like about Python: There are literals for variable length arrays, so you don't have to write code like that.) The difference from Python's approach is that there isn't an equivalent to Python's str/repr distinction. Obviously, when there's only one string conversion method, you won't use the wrong one. The other difference is that the built-in array types don't have a meaningful toString() method, so public class Foo { public static void main(String[] args) { String[] arr = {"a", "b", "c"}; System.out.println(arr); } } prints "[Ljava.lang.String;@df6ccd" (or something similar). | https://mail.python.org/pipermail/python-list/2004-June/269747.html | CC-MAIN-2019-04 | refinedweb | 288 | 67.76 |
BBC micro:bit
Potentiometer (MicroPython)
Introduction
The more powerful range of statements that you have in MicroPython makes it much easier to use simple components like potentiometers.
On this page, you will make a circuit with two potentiometers. We will take the readings from the potentiometers and convert them into numbers that represent coordinates on the LED matrix. You will have to do the rest of the work.
Circuit
With two potentiometers, we really need to use a breadboard. The alligator clips are fine for a single component but it becomes fiddly with any more than that.
The 3V and GND connections can be swapped around if you want the readings to be reversed.
Programming
This code is just the start. It is a simple way to test both the connections and the values you are getting. The program consists of an infinite while loop. The next two lines read the wiper pins of the potentiometers and store the values in variables a and b. The next two lines round the lines to make a number from 0 to 4. After a brief pause, the values are printed. If you press the REPL button, you will see the readings scrolling down the screen. Turn your knobs and you should be able to make them change from 0 to 4.
from microbit import * while True: a = pin0.read_analog() b = pin1.read_analog() a = int(4 * (a / 1023)) b = int(4 * (b / 1023)) sleep(50) print("x:" + str(a) + " y:" + str(b))
Challenges
- Obviously you need to map this onto some sort of sprite and use the potentiometers as inputs for a game.
- Maybe you are more interested in using the potentiometer value for something else. Perhaps you could use it to select a frequency to send to a buzzer or some headphones you have hacked.
- You could use the potentiometer readings to make some sort of display on the LED matrix. You could make something approximating a volume up/down image (a triangle) that fills as you turn the potentiometer.
- A potentiometer could also be wired up in series with any speaker you are using to make a volume adjustor. | http://www.multiwingspan.co.uk/micro.php?page=pypot | CC-MAIN-2019-47 | refinedweb | 358 | 73.07 |
how can i run an .exe using C++?
This is a discussion on run a program within the Windows Programming forums, part of the Platform Specific Boards category; how can i run an .exe using C++?...
how can i run an .exe using C++?
try this:
#include <shellapi.h> //You must link with shell32.lib
HINSTANCE ShellExecute(
HWND hwnd,
LPCTSTR lpVerb,
LPCTSTR lpFile,
LPCTSTR lpParameters,
LPCTSTR lpDirectory,
INT nShowCmd
);
where hwnd is the parent window
lpVerb is the verb, I mean what you want the function to do, you can set it to
"edit" Opens an editor. If lpFile is not a document file, the function will fail.
"explore" The function explores the folder specified by lpFile.
"open" The function opens the file specified by the lpFile parameter. The file can be an executable file or a document file. It can also be a folder.
"print" The function prints the document file specified by lpFile. If lpFile is not a document file, the function will fail.
"properties" Displays the file or folder's properties.
I think the rest are self-explanatory, except for nShowCmd, you can set it to. An application should call ShowWindow with this flag to set the initial show state of its main window..
if successful, it returns a value grater than 32
Good Luck
Oskilian | http://cboard.cprogramming.com/windows-programming/2623-run-program.html | CC-MAIN-2013-48 | refinedweb | 219 | 68.97 |
Setup
import numpy as np import tensorflow as tf from tensorflow import keras from tensorflow.keras import layers
Introduction.
Here's the shape:
inputs.shape
TensorShape([None, 784])
Here's the dtype: you get
x as the output. _________________________________________________________________ are almost identical. In the code version, the connection arrows are replaced by the call operation.
A "graph of layers" is an intuitive mental image for a deep learning model, and the functional API is a way to create models that closely mirrors this.
Training, evaluation, and inference
Training, evaluation, and inference work exactly in the same way for models
built using the functional API as for
Sequential models.
The
Model class offers a built-in training loop (the
fit() method)
and a built-in evaluation loop (the
evaluate() method). Note
that you can easily customize these loops
to implement training routines beyond supervised learning
(e.g. GANs).
Here, load the MNIST image data, reshape it into vectors, fit the model on the data (while monitoring performance on a validation split), then evaluate the=2, validation_split=0.2) test_scores = model.evaluate(x_test, y_test, verbose=2) print("Test loss:", test_scores[0]) print("Test accuracy:", test_scores[1])
Epoch 1/2 750/750 [==============================] - 3s 3ms/step - loss: 0.3430 - accuracy: 0.9035 - val_loss: 0.1851 - val_accuracy: 0.9463 Epoch 2/2 750/750 [==============================] - 2s 3ms/step - loss: 0.1585 - accuracy: 0.9527 - val_loss: 0.1366 - val_accuracy: 0.9597 313/313 - 0s - loss: 0.1341 - accuracy: 0.9592 Test loss: 0.13414572179317474 Test accuracy: 0.9592000246047974
For further reading, see the training and evaluation guide.
Save and serialize
Saving the model and serialization work the same way for models built using
the functional API as they do for
Sequential models.")
2021-08-25 17:50:55.989736: W tensorflow/python/util/util.cc:348] Sets are not currently considered sequences, but this may change in the future, so consider avoiding using them. INFO:tensorflow:Assets written to: path_to_my_model/assets
For details, read the model serialization & saving guide.
Use the same graph of layers to define multiple models
In the functional API, models are created by specifying their inputs and outputs in a graph of layers. That means that a single graph of layers can be used to generate multiple models.
In the example below, _________________________________________________________________
Here, the decoding architecture is strictly symmetrical
to the encoding architecture, so the output shape invoking it on an
Input or
on the output of another layer. By calling a model you aren't just reusing
the architecture of the model, you're also reusing its weights.
To see this in action, here's a different take on the autoencoder example that creates an encoder model, a decoder model, and chains (Functional) (None, 16) 18672 _________________________________________________________________ decoder (Functional) (None, 28, 28, 1) 9569 ================================================================= Total params: 28,241 Trainable params: 28,241 Non-trainable params: 0 _________________________________________________________________
As you can see,)
Manipulate complex graph topologies
Models with multiple inputs and outputs
The functional API makes it easy to manipulate multiple inputs and outputs.
This cannot be handled with the
Sequential API.
For example, if you're building a system for ranking customer, 0.2], )
Since the output layers have different names, you could also specify the losses and loss weights with the corresponding layer names:
model.compile( optimizer=keras.optimizers.RMSprop(1e-3), loss={ "priority": keras.losses.BinaryCrossentropy(from_logits=True), "department": keras.losses.CategoricalCrossentropy(from_logits=True), }, loss_weights={"priority": 1.0, "department": 0.2}, )
Train the model by passing lists of NumPy arrays of inputs and targets:
#, )
Epoch 1/2 40/40 [==============================] - 5s 9ms/step - loss: 1.2899 - priority_loss: 0.7186 - department_loss: 2.8564 Epoch 2/2 40/40 [==============================] - 0s 9ms/step - loss: 1.2668 - priority_loss: 0.6991 - department_loss: 2.8389 <keras.callbacks.History at 0x7fc1a66dc790> training and evaluation guide.
A toy ResNet model
In addition to models with multiple inputs and outputs,
the functional API makes it easy to manipulate non-linear connectivity
topologies -- these are models with layers that are not connected sequentially,
which the
Sequential API cannot handle.:
(x_train, y_train), (x_test, y_test) = keras.datasets.cifar10.load_data() x_train = x_train.astype("float32") / 255.0 x_test = x_test.astype("float32") / 255.0"], ) # We restrict the data to the first 1000 samples so as to limit execution time # on Colab. Try to train on the entire dataset until convergence! model.fit(x_train[:1000], y_train[:1000], batch_size=64, epochs=1, validation_split=0.2)
Downloading data from 170500096/170498071 [==============================] - 11s 0us/step 170508288/170498071 [==============================] - 11s 0us/step 13/13 [==============================] - 2s 29ms/step - loss: 2.3364 - acc: 0.1063 - val_loss: 2.2986 - val_acc: 0.0850 <keras.callbacks.History at 0x7fc19df22610>
Shared layers
Another good use for the functional API are models that use shared layers. Shared layers are layer instances that are reused multiple times in [==============================] - 15s 0us/step 574726144/574710816 [==============================] - 15: inputs = keras.Input((4,)) outputs = CustomDense(10)(inputs) model = keras.Model(inputs, outputs)
For serialization support in your custom layer,, implement the class method
from_config(cls, config) which is used
when recreating a layer instance given its config dictionary.
The default implementation of
from_config is:
def from_config(cls, config): return cls(**config)
When to use the functional API)))
Model validation while defining its connectivity graph the serialization & saving guide.
To serialize a subclassed model, it is necessary for the implementer
to specify a
get_config()
and
from_config() method at the model level.
Functional API weakness:
It does not support dynamic architectures
The functional API treats models as DAGs of layers. This is true for most deep learning architectures, but not all -- for example, recursive networks or Tree RNNs do not follow this assumption and cannot be implemented in the functional API..
Additionally, if you implement the
get_config method on your custom Layer or model,
the functional models you create will still be serializable and cloneable.
Here's a quick example of a custom RNN, written from scratch, being used you specify a static batch size for the inputs with the `batch_shape` # arg, because the inner computation of `CustomRNN` requires a static batch size # (when))) | https://www.tensorflow.org/guide/keras/functional?hl=hr | CC-MAIN-2022-40 | refinedweb | 998 | 50.23 |
So I was reading through David J. Eck's fantastic and free Introduction to Programming Using Java, and he mentioned the .charAt() function within the String class. I got thinking how I could use this in a program to practice an array of techniques. I thought of the idea of making a text based Hangman game. I planned it all out (more or less, I still need to work out how I'll terminate the program once the user has guessed the entire word correct, and how to end it when they've run out of guesses), but I've come into some trouble with using the .charAt() function itself.
I had a similar problem to this before (and the brilliant members of this forum helped me work it out) where I was using '==' when I should have been using .equals(). I tried this in the code below (in the if statement inside the nested for loop) but it just stops the program from running at all.
I feel this is going to be something stupid... well, there is still the possibility that the whole structure of my program is off (it was late when I planned it, xD).
Any help would be very much appreciated, :). I'm on my summer holiday now so I'm keen to learn lots and lots of Java!
This was how I tried it with .equals():
Code :
if (guess.charAt(0).equals(actualWord.charAt(counter))){ isItCorrect = true; }else{};
This is the rest of the code, with '==' being used:
Code :
import java.util.Scanner; class HangmanGame { public static void main(String[] args) { Scanner input = new Scanner(System.in); String actualWord; //The word to be guessed. String guess; //Hold the single letter guess. boolean isItCorrect = false; // To determine whether the user should have the guess counted as failed, thus losing them a guess. int counter; int i; //actualWord is given a value. //Messages are displayed to the user. System.out.println("Please enter the word you would like the other player to guess: "); actualWord = input.nextLine(); System.out.println("Next player, guess the letters. The word contains " + actualWord.length() + " letters."); //1st for loop = the "Guesses Loop": gets the result of isItCorrect from its nested for loop and then sorts out how many guesses are left. //2nd for loop = does the actual comparing of guess to actualWord, cycling through each letter with charAt(counter). for(i = 0; i <=10; i++){ isItCorrect = false; //reseting isItCorrect at the start of each guess, so that a 'Correct!' does not carry over to the next guess. System.out.println("Please guess a letter: "); guess = input.nextLine(); for(counter = 0; counter <= actualWord.length(); counter++){ if (guess.charAt(0) == actualWord.charAt(counter)){ isItCorrect = true; }else{}; } if(isItCorrect = true){ System.out.println("Correct! Letter " + guess + "found at index no. I DONT KNOW!" /*+ SOMEHOWGETTHEINDEXOFTHELETTER)*/); counter = counter - 1; }else{System.out.println("Incorrect. Attempts remaining: " + (10 - counter));} }//end of 1st for loop; "Guesses Loop". } }
Output:
Code :
Please enter the word you would like the other player to guess: cat Next player, guess the letters. The word contains 3 letters. Please guess a letter: c Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: 3 at java.lang.String.charAt(String.java:686) at HangmanGame.main(HangmanGame.java:29) | http://www.javaprogrammingforums.com/%20loops-control-statements/16401-if-statement-%3D%3D-equals-problems-charat-printingthethread.html | CC-MAIN-2015-11 | refinedweb | 545 | 68.16 |
In the first part of this two-article series, we explored rolling your own WordPress GraphQL adapter, inspired by the work done by GatsbyJS, written in Javascript and hosted on GraphCool. In this article, we’ll build the same thing, this time using Java. Spring Boot and GraphQL Java Kickstart make this quite easy.
Pre-requisites
For anyone joining us now – you need to go through the first part of the previous article and enable the WordPress REST API – as well as get an authentication token. As in the previous article, building a full OAuth2 service is out of scope, so we’ll again simply get a token via curl and hard-code it into our application.
Dependencies
From the Spring Boot side of things, use Spring Initializer to add “Web” or “Reactive Web” ( I went with the latter). The official documentation of GraphQL Java Kickstart makes the GraphQL side of things quite simple as well:
Add the dependencies listed in the above documentation and you’re good to go. If you’ve got everything installed properly, running the application as-is will allow you to access the GraphQL playground on. This is why GraphQL Spring Boot is so useful – you have a fully functional GraphQL environment right off the bat – minimal configuration required!
Ensuring Reactive Web works
Strictly speaking you don’t need to do this – heck GraphQL will work without Spring Web or Spring Reactive Web at all. However, you probably would want your Spring application to serve additional content apart from the GraphQL data, so I included this section. besides, Spring Boot makes serving content over Reactive Web a breeze. Create a new file (HelloController), and insert the following:
package com.example.demo; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.RestController; @RestController public class HelloController { @GetMapping("/hello") public String handle() { return "Hello WebFlux"; } }
Not counting package and import statements, that’s a hello world using webflux in under 10 lines of code. The annotations in the code also make it pretty self-explanatory. We define a class that acts as a REST Controller, which will respond to a single path via a mapping: GET requests to “/hello“. Restarting your app and visiting should return “Hello Webflux“. Fleshing this out to something more useful is left as an exercise for the reader.
Defining our GraphQL schema
One of GraphQL’s strengths is the ability to have a fixed (but very flexible) schema which is akin to introducing static typing to REST APIs. The schema allows your programming environment to know what type of queries to expect, and what type of responses it should send out. This in turn makes validation and autocompletion easier. This is where we encounter the second benefit of using GraphQL Spring Boot. In order to define the schema, we simply need to create a file ending in .graphqls anywhere in our classpath (typically under the “resources” folder). Go ahead and create such a file, and use the following code:
type Query { posts(count: Int): [Post] } type Post { title: String! content: String! }
Note the similarities between the above, and our schema defined in the previous article for GraphCool. The majority is exactly the same (another benefit of using GraphQL schemas – a common language that developers using different programming languages can still understand – a benefit similar to SQL in that sense), however we still note a couple of differences:
- the lack of the extend keyword. To make things easier, GraphCool includes a root Query type in a separate file, here we’re using a single file to define our schema so we don’t need the extend keyword
- the lack of @annotations. Again since we’re not using GraphCool, we can do without these. The above is a plain vanilla GraphQL schema
Defining our GraphQL Resolver
So, right now GraphQL knows our schema, i.e. the structure of expected queries and the structure of the responses it should serve. But how should it actually get the data to serve such requests? This is the job of a “resolver”. It’s a class whose job is to “resolve” queries into actual data.
GraphQL Java Kickstart makes this easy by introducing an interface named GraphQLQueryResolver. So we simply need to create a file, and code a class which implements this interface, like so:
package com.example.demo.resolvers; import com.coxautodev.graphql.tools.GraphQLQueryResolver; import com.example.demo.types.Post; import com.example.demo.types.Posts; import org.springframework.http.HttpEntity; import org.springframework.http.HttpHeaders; import org.springframework.http.HttpMethod; import org.springframework.http.ResponseEntity; import org.springframework.stereotype.Component; import org.springframework.web.client.RestTemplate; import java.util.List; @Component public class Query implements GraphQLQueryResolver { HttpHeaders headers = new HttpHeaders(); List<Post> posts( int count ) { if (count == 0) { count = 2; } headers.set("Authorization", "Bearer xyz"); HttpEntity<String> entity = new HttpEntity<>("parameters", headers); RestTemplate restTemplate = new RestTemplate(); ResponseEntity<Posts> response = restTemplate.exchange( ""+count, HttpMethod.GET, entity, Posts.class); System.out.println(response.toString()); return response.getBody().getPosts(); } }
A couple of pointers on the above code:
- The name of the class method matches the name of the query defined in the schema (posts). If you have multiple queries in your schema, you’d have multiple methods each with the same name as the queries defined in the schema
- The class method accepts as an argument the same name and type (int count) of argument we defined in our schema for this particular query
- Note the use of Spring’s RestTemplate and HttpHeaders to create a typical GET request including our Authorization Bearer header to the WordPress REST API.
- Note how we use the exchange method of RestTemplate to decode the received data into the Posts.class type. We still need to define this class, but defining this allows us to retrieve a POJO rather than deal with raw JSON. The following link is recommended reading to get some background:
Defining our JSON types
As we mentioned in the last point above, we need to define classes to allow RestTemplate to decode the raw JSON returned from the WordPress API into an easier to use POJO. Now, if you observe the JSON response from the API, you’ll note two things:
- There are a LOT of fields. We’re not interested in all of them, only a subset.
- The individual POST objects are wrapped in an array named POSTS, something like so:
{ "posts" : [ {...first post...}, {...second post...}, {... you get the idea...} ] }
This means that we need to define TWO classes. The first – post – will describe the inner objects in the array that describe individual posts. The second – posts – will describe the outer object that contains the array. This latter is quite simple:
package com.example.demo.types; import com.fasterxml.jackson.annotation.JsonIgnoreProperties; import java.util.List; @JsonIgnoreProperties(ignoreUnknown = true) public class Posts { private List<Post> posts; public Posts(){}; public void setPosts(List<Post> posts){ this.posts = posts; } public List<Post> getPosts(){ return this.posts; } }
We simply need to define:
- An empty constructor
- a private class List variable that’s going to store our array of posts
- Getters and Setters for the above class variable
Note that we annotate this class with the @JsonIgnoreProperties(ignoreUnknown = true) property, This solves our first observation above, and allows us leave all the other fields returned in the JSON response as undefined in the POJO.
We’re left with defining the Post POJO:
package com.example.demo.types; import com.fasterxml.jackson.annotation.JsonIgnoreProperties; @JsonIgnoreProperties(ignoreUnknown = true) public class Post { private String title; private String content; public Post() { } public String getTitle() { return title; } public void setTitle(String title) { this.title = title; } public String getContent() { return content; } public void setContent(String content) { this.content = content; } @Override public String toString() { return "Post {" + "title='" + title + '\'' + ", content=" + content + '}'; } }
In this case, we’re interested in the “Title“, and “Content” fields of the JSON response for the post type, so in the above code note that we define two private class variables – one for each of the JSON fields we’re interested in. We then define getters and setters for these variables, and last but not least we also override the “toString” method to allow us to more easily log the responses
Conclusion
That should be it, you’re golden if you can open the aforementioned GraphiQL playground and run a query with a successful response similar to the below:
| http://blog.davidvassallo.me/2019/01/23/part-2-inspired-by-gatsby-js-rolling-your-own-graphql-powered-wordpress-api-this-time-with-spring-boot/?shared=email&msg=fail | CC-MAIN-2019-18 | refinedweb | 1,397 | 54.63 |
need help to making change
I have read textbook a lot but i still dont know what to do next steps.
Here is problem.
The program should prompt the user for and accept two inputs:
1. The price (including any applicable tax, etc.) for whatever was purchased by the
customer.
2. The amount of money provided to the cashier by the customer
Given this information, the program should provide output as follows
• Display appropriate messages if the customer provided to little money or the exact
amount.
• Otherwise, display the number of bills and coins that should be given to the customer
as change.
• Change should be provided using the largest bill and coin denominations as possible.
The available bill denominations are $20, $10, $5 and $1; the available coin
denominations are 25¢, 10¢, 5¢, 1¢ (there are no half-dollar coins). For example, if
the change amount is $26.56, the customer should be given one $20 bill, one $5 bill,
one $1 bill, two quarters, one nickel, and one penny.
• Denominations that are not used should not be displayed. For example, in Sample
Run 2 below, the dime coin is not included in the output.
Important: You should store all of your amounts as cents using Java’s int type, not double.
In order to allow users of your program to enter amounts normally, you should convert entered
dollar amounts to cents by multiplying by 100 and “casting” from double to int, e.g.:
int price = (int) Math.round(keyboard.nextDouble()*100);
Sample Run 1
Enter the purchase price: 13.44
Enter amount provided by customer: 15.00
The customer should be given change as follows:
1 $1 bill(s)
2 quarter coin(s)
1 nickel coin(s)
1 penny coin(s)
Sample Run 2
Enter the purchase price: 13.44
Enter amount provided by customer: 13.44
No change is necessary!!
Sample Run 3
Enter the purchase price: 26.14
Enter amount provided by customer: 100.00
The customer should be given change as follows:
3 $20 bill(s)
1 $10 bill(s)
3 $1 bill(s)
3 quarter coin(s)
1 dime coin(s)
1 penny coin(s)
please help
this is what i have so far
import java.util.Scanner; public class changeMaker { /** * */ public static void main(String[] args) { Scanner keyboard= new Scanner(System.in); int price; int provided; int change; int ones= 0, fives= 0, tens= 0, twenties= 0; int pennies= 0, nickels= 0, dimes= 0, quaters= 0; System.out.print("Enter the purchase price:"); price = (int)Math.round(keyboard.nextDouble()*100); System.out.print("Enter the amount given by the customer:"); provided = (int) Math.round(keyboard.nextDouble()*100); | https://www.daniweb.com/programming/software-development/threads/384560/java-program-to-make-change-please-help | CC-MAIN-2017-43 | refinedweb | 444 | 65.42 |
Note: Before going into this tutorial, it is advised to have better knowledge of Applet.
What mouse events and key events possible with frame are also possible with applet because frame and applet are containers (that can hold AWT components) derived from the same java.awt.Container class. Following is their hierarchy.
As usual every applet file should be accompanied by a HTML file.
Following two programs of MouseListener Example illustrate.
HTML file to run the applet
Java applet File Name: AppletMouseListener.java
No main() method and no constructor, it is being an applet.
public class AppletMouseListener extends Applet implements MouseListener
Observe, the applet implements MouseListener.
addMouseListener(this);
Applet window is added with MouseListener in init() method.
The paint() method should be called with repaint() only. Calling paint() directly raises compilation error. Why?
g.drawString(str, 75, 150);
The string str is drawn in applet window with Graphics class drawString() method at x coordinate of 75 and y coordinate of 150.
Output screen when mouse is clicked on applet window of MouseListener Example. | http://way2java.com/awt-events/java-applet-tutorial-mouselistener-mouseevent-mouse-input-example/ | CC-MAIN-2017-13 | refinedweb | 173 | 50.02 |
Given a n x n strictly sorted matrix and a value x. The problem is to count the elements smaller than or equal to x in the given matrix. Here strictly sorted matrix means that matrix is sorted in a way such that all elements in a row are sorted in increasing order and for row ‘i’, where 1 <= i <= n-1, first element of row 'i' is greater than or equal to the last element of row 'i-1'.
Examples:
Input : mat[][] = { {1, 4, 5}, {6, 10, 11}, {12, 15, 20} } x = 9 Output : 4 The elements smaller than '9' are: 1, 4, 5 and 6. Input : mat[][] = { {1, 4, 7, 8}, {10, 10, 12, 14}, {15, 26, 30, 31}, {31, 42, 46, 50} } x = 31 Output : 13
Naive Approach: Traverse the matrix using two nested loops and count the elements smaller than or equal to x. Time Complexity is of O(n^2).
Efficient Approach: As matrix is strictly sorted, use the concept of binary search technique. First apply the binary search technique on the elements of the first column to find the row index number of the largest element smaller than equal to ‘x’. For duplicates get the last row index no of occurrence of required element ‘x’. Let it be row_no.. If no such row exists then return 0. Else apply the concept of binary search technique to find the column index no of the largest element smaller than or equal to ‘x’ in the row represented by row_no. Let it col_no. Finally return ((row_no) * n) + (col_no + 1). The concept of binary search technique can be understood by the binary_search function of this post.
C++
Java
Python3
C#
PHP
Output:
Count = 13
Time Complexity: O(Log2n).
Attention reader! Don’t stop learning now. Get hold of all the important DSA concepts with the DSA Self Paced Course at a student-friendly price and become industry ready.
Recommended Posts:
- Count of smaller or equal elements in sorted array
- Count smaller elements in sorted array in C++
- Search equal, bigger or smaller in a sorted array in Java
- Length of longest subarray in which elements greater than K are more than elements not greater than K
- Count elements less than or equal to a given value in a sorted rotated array
- Print all elements in sorted order from row and column wise sorted matrix
- heapq in Python to print all elements in sorted order from row and column wise sorted matrix
- Find the element before which all the elements are smaller than it, and after which all are greater
- Number of elements smaller than root using preorder traversal of a BST
- Count of strings in the first array which are smaller than every string in the second array
- Count nodes from all lower levels smaller than minimum valued node of current level for every level in a Binary Tree
- Count elements such that there are exactly X elements with values greater than or equal to X
- Count of Array elements greater than or equal to twice the Median of K trailing Array elements
- First strictly smaller element in a sorted array in Java
- Nearest smaller character to a character K from a Sorted Array
- Find element in a sorted array whose frequency is greater than or equal to n/2.
- Maximize number of groups formed with size not smaller than its largest element
- Count of Array elements greater than all elements on its left and at least K elements on its right
- Count of Array elements greater than all elements on its left and next K elements on its right
- For each element in 1st array count elements less than or equal to it in 2 | https://www.geeksforgeeks.org/count-elements-smaller-equal-x-sorted-matrix/?ref=rp | CC-MAIN-2020-45 | refinedweb | 618 | 57.44 |
I'm trying to populate an array with numbers 1-10 of size 100 and then finding the average of the array and i can't seem to figure out where i'm going wrong. (the multiple methods are required...also i'm not too sure how to correctly use multiple methods. possibly where i'm going wrong.)
import java.util.Random; public class wtf { public static void main(String[] args) { int [] values = new int [100]; populateArray(values); } public static void populateArray (int []values ) { Random generator = new Random(); for (int z = 0; z < values.length; z++) { values[z] = generator.nextInt(10) + 1; } average (values); } public static void average (int values [] ) { int sum = 0; for (int r = 0; r < values.length; r++) { sum = sum + values [r]; sum = sum/values.length; } System.out.println ("The average is " + sum); } } | http://www.javaprogrammingforums.com/whats-wrong-my-code/5564-array-trouble.html | CC-MAIN-2019-39 | refinedweb | 136 | 58.38 |
Secondary expressions (ref)
From Nemerle Homepage
<< Back to Reference Manual.
Secondary Expressions
This section describes expressions that are in fact just syntactic sugar over Core Expressions. We just present a translation of Secondary Expressions into Core Expressions.
Conditional expression
A standard branch, which executes and returns value of first expression if the condition evaluates to true or second elsewhere.
Internally it is translated into
match (cond) { | true => expr1 | false => expr2 }
While loop
A loop, executing body expression as long as the condition is true. Its value is always checked before the execution of body and if it evaluates to false, then the loop ends. The body must be of type void.
The loop is translated internally into the following code
def loop () { if (cond) { body; loop () } else () }; loop ()
do ... while loop
This loop is similar to while loop, but body is executed before the first time the condition is checked.
When expression
A version of the if condition, but having only one branch -- execution of body only when the condition is satisfied. If its value if false, then nothing is done (i. e. () is returned).
Its semantics is the same as
if (cond) body else ()
Unless expression
An opposite version of when. It executes and returns value of body only if conditions are not satisfied (i. e. evaluates to false).
Its semantics is the same as
if (cond) () else body
Lambda expression
Lambda expressions can be thought as of anonymous local functions. This construct defines such a function and returns it as a functional value. This value can be used just like the name of a regular local function.
Example:
List.Iter (intList, fun (x) { printf ("%d\n", x) })
is equivalent to
def tmpfunc (x) { printf ("%d\n", x) }; List.Iter (intList, tmpfunc)
List constructor
[1, 2, 3] is translated to list.Cons (1, list.Cons (2, list.Cons (3, list.Nil ()))).
Swap operator
Infix operator <-> is used to swap values of two assignable expressions. You can think about it as being translated to
def temp = e2; e2 = e1; e1 = temp
except that subexpressions of e1 and e2 are evaluated only once (there is a special macro to assure this), so
a[x.Next()] <-> a[x.Next()]
can be used safely. | http://nemerle.org/Secondary_expressions_%28ref%29 | crawl-001 | refinedweb | 371 | 65.32 |
My program is meant for two players. rooled and the sum is determined, and the main game. When I run the program, I receive these errors from the diceGame class. I would like to know why these errors are appearing. My code is not complete yet.
- getHoldA() in playerGame cannot be applied to (int)
- getHoldB() in playerGame cannot be applied to (int)
This is the player classThis is the player classCode:import java.io.*; import java.lang.*; import java.util.*; public class diceGame { public static void main(String[] args) { pairOfDice dice; dice = new pairOfDice(); playerGame player; player = new playerGame(); int rollCount = 0; int holdA = 0, holdB = 0; do { dice.roll(); // Roll the first pair of dice. System.out.println("Dice 1: " + dice.getDiceA() + "\n" + "Dice 2: " + dice.getDiceB() + "\n" + "The total is: " + dice.getTotal()); System.out.println("Do you want to hold the fist dice with a value of " + dice.getDiceA()); if (holdA == 1){ player.getHoldA(); player.getHoldA(dice.getDiceA()); System.out.println("Value of dice A is held"); } System.out.println("Do you want to hold the second dice with a value of " + dice.getDiceB()); if (holdB == 1){ player.getHoldB(dice.getDiceB()); System.out.println("Value of dice B is held"); } rollCount++; } while (dice.getTurns() <= 3); } }
And this is the pairOfDice classAnd this is the pairOfDice classCode:import java.io.*; public class playerGame { private int holdA = 0, holdB = 0; //constructor public playerGame(){ } public void setHoldA (int valA){ holdA = valA; } public void setHoldB (int valB){ holdB = valB; } public void setPlayer(int player){ player = player + 1; } public int getHoldA () { return holdA; } public int getHoldB () { return holdB; } }
Code:import java.io.*; public class pairOfDice { private int diceA = 0, diceB = 0, turns = 0; public pairOfDice() {//constructor roll(); } public void roll(){ diceA = (int)(Math.random()*6) + 1; diceB = (int)(Math.random()*6) + 1; turns = turns +1; } public void setDice(int newDiceA, int diceA) { diceA = newDiceA; } public void setDiceB(int newDiceB, int diceB) { diceB = newDiceB; } public void setTurns(int turns) { turns = 0; } public int getDiceA() { return diceA; } public int getDiceB() { return diceB; } public int getTotal() { return (diceA + diceB); } public int getTurns() { return turns; } } | http://forums.devshed.com/java-help/952534-objects-classes-methods-program-trouble-last-post.html | CC-MAIN-2017-34 | refinedweb | 348 | 66.13 |
Azure Pipelines PR Reviewer
An Azure Pipelines pull request review service, built on Azure Container Instance, Azure Logic App and Azure Service Bus.
How it works
When a Azure Pipelines pull request is created or updated, Azure Pipelines sends a notification to an Azure Service Bus topic. As a subscriber of the topic, an Azure Logic App starts an Azure Container Instance upon getting the notification. The container in Azure Container Instance utilizes Azure Pipelines REST API to check the changes in the pull request, leave comments and vote approve/wait.
How to deploy
Deploy ARM template
The ARM template deployment deploys Logic App, Service Bus Namepsace and Topic, it also registers Logic App as a subscriber of the Service Bus Topic. Logic App is configured to start a Container Instance with docker image wenwu/pr-review when getting a message from the Service Bus topic.
Authorize ACI connection in Logic App
To grant Logic App the permission to create Container Instance, we need to authorize ACI connection in Logic App.
After deployment, navigate to the resource group in Azure portal, open the logic app resource:
Open designer (click "Edit" button), click "Connections" in the flow:
Click "Invalid connection" to configure connection:
Click "Save" button to save the changes.
Configure Azure Pipelines
Configure Service Hook
Service hooks enable you to perform tasks on other services when events happen in your Azure Pipelines projects. We will configure service hook so that message will be sent to Serivce Bus Topic when pull request is created.
Get service bus topic connection string with commands,
<resource-group-name>is the name of resource group used for ARM template deployment:
groupName=<resource-group-name> nsName=$(az servicebus namespace list -g $groupName | jq -r ".[0].name") az servicebus topic authorization-rule keys list -g $groupName --namespace-name $nsName --topic-name vsts-pr-update -n vsts-hook | jq -r ".primaryConnectionString" | rev | cut -d ';' -f2- | revCopy the connection string. You will need to provide this value when creating a Service Hook subscription.
Go to Azure Pipelines project to configure service hook.
Click "Create subscription"
Select "Azure Service Bus" and click "Next".
Select "Pull Request created" trigger, configure "Repository", "Target branch" and other filters if applies, click "Next".
Select "Send a message to a Service Bus Topic" at "Perform this action", input the connection string got in step 1 at "SAS connection string", input "vsts-pr-update" at "Topic name", click "Test" to test, then click "Finsh".
Optionally, another subscription can be created to send message when a pull request is updated.
Get VSTS personal access token
The reviewer application running in Azure Container Instance uses a Azure Pipelines personal access token to read, comment and vote on a pull request.
Log in Azure Pipelines, go to your security details.
Create a personal access token
Select the "Code (read and write)" scope for the token, click "Save"
When you're done, make sure to copy the token. You'll use this token in next step.
Treat the token as secret, the token is your identity and acts as you when it is used.
Upload VSTS config
The reviewer application running in Azure Container Instance reads configuration file on an Azure Storage File Share to get the personal access token and other Azure Pipelines information.
Download the config.json as a template, change the value according to your Azure Pipelines project.
userId can be get via Accounts API (
accountId in response ) or Get Pull Request API (
createdBy.Id in response )
Use Azure Portal to upload the
config.json file to Azure Storage File Share, navigate to the resource group in Azure portal, open the storage resource (resource name may vary):
Click "Files",
Click "vsts-pr-preview", then click "config",
Click "Upload", use the file upload control to upload the
config.json file.
Now your pull request review service is up and running! | https://azure.microsoft.com/en-us/resources/samples/aci-vsts-pr-reviewer-logicapps-servicebus/ | CC-MAIN-2019-43 | refinedweb | 642 | 51.38 |
How to create multiple refs in React with useRef
July 27, 2020
In this article, you’ll also learn how to copy text inside multiple input fields in React using useRef.
I needed to create multiple readonly input fields in a React component that a user can then click a button to select copy the text inside that input field. It took me a couple of hours to figure it out.
After reading several stackoverflow articles, here’s exactly how you do it.
- First, import useRef()
import React, { useRef, useState, useEffect } from "react"
- Declare your Refs. The default value should be an array.
let usernameRefs = useRef([])
- Dynamically create as many refs as you want. Assume we will have 4 input elements on the page — so we use an array with a length of 4.
usernameRefs.current = [0, 0, 0, 0].map( (ref, index) => (usernameRefs.current[index] = React.createref()) )
- Create a function to handle copying the input field.
const handleCopyUsername = (e, index) => { usernameRefs.current[index].current.select() document.execCommand("copy") }
- Finally, create the 4 input elements.
;[0, 0, 0, 0].map((el, index) => { return ( <div> <input type="text" readonly ref={usernameRefs.current[index]} value={index} /> )<button onClick={handleCopyUsername}>Click to copy text </button>{" "} </div> ) })
- And that’s it. When you click your click to copy text button, you should get have the input value(in our case just the index, copied to the clipboard)
Here’s a link to the Github gist for the full code. Gist | https://blog.adebola.dev/how-to-create-multiple-refs-in-react-with-useref/ | CC-MAIN-2021-21 | refinedweb | 246 | 58.28 |
Check for the
latest version of this e-book:
This e-book is published under Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported
License. To view a copy of this license:
If you would like to contact us:
If you would like to support us:
Disclaimer: While we at the Utilize Windows strive to make the information in this book as timely and accurate
as possible, we make no claims, promises, or guarantees about the accuracy, completeness, or adequacy of the
contents of this book, and expressly disclaim liability for errors and omissions in the contents of this book.
Microsoft Windows® 7 is registered trademark of Microsoft Corporation in the United States and/or other
countries.
Contents
Basics ........................................................................................................................................................................................ 1
Introduction to Windows 7 .............................................................................................................................................. 1
Creating a Windows 7 USB Installation Source ........................................................................................................... 4
Upgrading to Windows 7 - Overview ............................................................................................................................ 9
Migrating to Windows 7 using WET............................................................................................................................ 10
Migrating to Windows 7 using USMT ......................................................................................................................... 15
Networking ............................................................................................................................................................................ 21
Configuring IPv4 in Windows 7.................................................................................................................................... 21
Configuring IPv6 in Windows 7.................................................................................................................................... 25
Internet Connection Sharing (ICS) Configuration in Windows 7 ........................................................................... 28
Working With Wireless Network Connections in Windows 7 ................................................................................ 32
Working with Windows Firewall in Windows 7 ......................................................................................................... 38
Configuring Windows Firewall with Advanced Security in Windows 7................................................................. 43
Configuring BranchCache in Windows 7 .................................................................................................................... 51
Creating a VPN Connection in Windows 7 ................................................................................................................ 55
DirectAccess Feature in Windows 7............................................................................................................................. 59
Deployment ........................................................................................................................................................................... 62
Preparing for Windows 7 Image Capture .................................................................................................................... 62
Mounting and Unmounting Windows 7 Image Using ImageX and DISM ........................................................... 66
Creating WinPE Using WAIK for Windows 7 .......................................................................................................... 76
Windows 7 Image Capture Demonstration................................................................................................................. 80
Windows 7 Image Deployment Demonstration ........................................................................................................ 85
Managing Existing Windows 7 Images ........................................................................................................................ 91
Servicing Windows 7 Image Using DISM ................................................................................................................... 98
Applying Updates to Windows 7 Image Using DISM ............................................................................................ 105
Creating Virtual Hard Disk (VHD) using Disk Management in Windows 7 ...................................................... 108
Creating Virtual Hard Disk (VHD) using Diskpart in Windows 7 ....................................................................... 113
Management ........................................................................................................................................................................ 117
Advanced Driver Management in Windows 7.......................................................................................................... 117
Staging a Driver in Windows 7 .................................................................................................................................... 125
Using Disk Management and Diskpart to Mange Disks in Windows 7 ............................................................... 128
Disk Quotas in Windows 7 .......................................................................................................................................... 136
Disk Defragmenter Tool in Windows 7 .................................................................................................................... 140
Removable Storage and System Security in Windows 7.......................................................................................... 142
Application Compatibility Issues in Windows 7....................................................................................................... 144
UAC Configuration in Windows 7 ............................................................................................................................. 148
Configuring Security Zones in Windows 7 ............................................................................................................... 151
Printer Configuration in Windows 7 .......................................................................................................................... 160
Configuring Power Options in Windows 7 ............................................................................................................... 165
Configuring Offline Files in Windows 7 .................................................................................................................... 172
Managing Services in Windows 7 ................................................................................................................................ 177
Using msconfig in Windows 7 ..................................................................................................................................... 183
Event Viewer in Windows 7 ........................................................................................................................................ 188
Monitoring Performance in Windows 7 .................................................................................................................... 196
Using WinRS and PowerShell for Remote Management in Windows 7 .............................................................. 207
Configuring and Using Remote Desktop in Windows 7 ........................................................................................ 212
Remote Assistance in Windows 7 ............................................................................................................................... 223
System Recovery in Windows 7 .................................................................................................................................. 231
Security ................................................................................................................................................................................. 239
Credential Manager in Windows 7 .............................................................................................................................. 239
Running Apps as Different Users with Run As in Windows 7 ............................................................................. 245
User Account Policies in Windows 7 ......................................................................................................................... 250
Editing NTFS Permissions in Windows 7................................................................................................................. 254
Advanced Sharing Settings in Windows 7 ................................................................................................................. 264
Working With Shared Folders in Windows 7 ........................................................................................................... 269
HomeGroups in Windows 7 ........................................................................................................................................ 276
Configuring Auditing in Windows 7........................................................................................................................... 280
Encrypting File System in Windows 7 ....................................................................................................................... 285
Configuring BitLocker in Windows 7 ........................................................................................................................ 294
Configuring BitLocker to Go in Windows 7 ............................................................................................................ 300
Windows Defender in Windows 7 .............................................................................................................................. 305
Optimization........................................................................................................................................................................ 310
Monitoring Resources in Windows 7 ......................................................................................................................... 310
Using Reliability Monitor in Windows 7.................................................................................................................... 321
Visual Effects and Paging File Options in Windows 7 ........................................................................................... 326
Configuring WSUS and Other Update Options in Windows 7 ............................................................................. 339
Setting Up Backup in Windows 7 ............................................................................................................................... 344
Restoring Data from Backup in Windows 7 ............................................................................................................. 354
Basics
Introduction to Windows 7
Basics
Introduction to Windows 7
Before you start
Objectives: learn about main features in each Windows 7 edition and what minimum hardware requirements
are
Prerequisites: no prerequisites.
Key terms: windows 7 editions, starter, home basic, home premium, professional, enterprise, ultimate,
hardware requirements, processor architecture.
Windows 7 Editions
There are six different Windows 7 editions:
Starter
Home Basic
Home Premium
Professional
Enterprise
Ultimate
Starter
Windows 7 Starter edition does not support DVD playback, Windows Aero user interface, IIS Web Server,
Internet connection sharing, or Windows Media Center. It also does not support advanced, new features like
AppLocker, Encrypting File System, DirectAccess, BitLocker, BranchCache, and Remote Desktop Host. It
supports only one physical processor.
Home Basic
Window 7 Home Basic does not support domains, Aero user interface, DVD playback, Windows Media
Center, or IIS Web Server. It also does not support enterprise features such as EFS, AppLocker, DirectAccess,
BitLocker, Remote Desktop Host, and BranchCache. It supports only one physical processor. The x86 version
supports a maximum of 4 GB of RAM, whereas the x64 version supports a maximum of 8 GB of RAM.
Home Premium.
1
Basics
Introduction to Windows 7
Professional
Windows 7 Professional supports all the features available in Windows Home Premium, and it also supports
domains. It supports EFS and Remote Desktop Host but does not support enterprise features such as
AppLocker, DirectAccess, BitLocker, and BranchCache.
Enterprise
Windows 7 Enterprise and Ultimate Editions support all the features available in all other Windows 7 editions
but also support all the enterprise features such as EFS, Remote Desktop Host, AppLocker, DirectAccess,
BitLocker, BranchCache, and Boot from VHD. Windows 7 Enterprise and Ultimate editions support up to
two physical processors. Windows 7 Enterprise is available only to Microsoft's volume licensing customers, and
Windows 7 Ultimate is available from retailers and on new computers installed by manufacturers.
Although some editions support only one physical processor, they do support an unlimited number of cores on
that processor. For example, all editions of Windows 7 support quad-core CPUs. We can use Remote Desktop
to initiate a connection from any edition of Windows 7, but we can connect to computers running Windows 7
Professional, Windows 7 Ultimate, or Windows 7 Enterprise. We can't use Remote Desktop Connection to
connect to computers running Windows 7 Starter, Windows 7 Home Basic, or Windows 7 Home Premium. minimum
hardware requirements:
1 GHz 32-bit (x86) or 64-bit (x64) processor
1 GB of system memory
40-GB hard disk drive (traditional or SSD) with at least 15 GB of available space
Graphics adapter that supports DirectX 9 graphics, has a Windows Display Driver Model (WDDM)
driver, Pixel Shader 2.0 hardware, and 32 bits per pixel and a minimum of 128 MB graphics memory
32-bit versus 64-bit
Windows 7 supports two different processor architectures: 32-bit (x86) version, and 64-bit (x64) version. The
main limitation of the x86 version of Windows 7 is that it does not support more than 4 GB of RAM. It is
possible to install the x86 version of Windows 7 on computers that have x64 processors, but the operating
2
Basics
Introduction to Windows 7
system will be unable to utilize any RAM that the computer has beyond 4 GB. We can install the x64 version
of Windows 7 only on computers that have x64-compatible processors. The x64 versions of Windows 7
Professional, Enterprise, and Ultimate editions support up to 128 GB of RAM. The x64 version of Windows 7
Home Basic edition supports 8 GB and the x64 edition of Home Premium supports a maximum of 16 GB.
3
Basics
Creating a Windows 7 USB Installation Source
Creating a Windows 7 USB Installation Source
Before you start
Objectives: learn how to create USB installation source by using tools available on your PC.
Prerequisites: you have to have a Windows 7 installation DVD and a USB storage device with at least 4 GB
of free space.
Key terms: command prompt, elevated mode, usb drive preparation, diskpart, diskpart commands, bootable
usb drive, windows 7 installation, source
Procedure
Before we begin keep in mind that during this process USB flash drive will be completely erased, so we have to
make sure that we save any data that it contains. In our example we have a Windows 7 installation DVD
present in our D drive, and a USB flash drive available trough drive E, as shown on the picture.
Figure 1 - Computer Drives
1. Open Command Prompt (CMD)
We will be working with Command Prompt in elevated mode. You can find CMD in: Start menu > All
Programs > Accessories > Command Prompt. To open CMD in elevated mode, right-click on the
Command Prompt and select 'Run as administrator'. Click Yes to confirm.
Figure 2 - Run CMD as Administrator
4
Basics
Creating a Windows 7 USB Installation Source
We know that we are running CMD in elevated mode because we have the 'Administrator' in the name of the
CMD window.
Figure 3 - Administrator: Command Prompt
2. Prepare USB drive
We will open the command line utility called diskpart, which is used to manage partitions and drives. To do
that we will simply enterdiskpart in CMD.
Figure 4 - Diskpart
Next, we will enter: list disk. With this command we can view all the available disks on our computer.
Figure 5 - List Disk
In our example, Disk 0 is the hard drive. We know that because the size of our internal hard disk is 40GB. The
size of our USB flash drive is 4 GB (3875 MB to be more precise). To work with USB drive we need to select
it. To do that, in our case, we have to type in: select disk 1.
Figure 6 - Select Disk 1
After the selection we will clean the USB drive. We have to wipe out any partition information and anything on
it. To do that we will type in: clean.
5
Basics
Creating a Windows 7 USB Installation Source
Figure 7 - Clean
After the cleaning, notice that, if we browse to the Computer, our USB drive now changed. There is no info
shown about the free space.
Figure 8 - USB drive in Windows Explorer
Now we need to create the partition on our USB drive. To do that, in Command Prompt we will enter: create
partition primary.
Figure 9 - Create Partition Primary
After that we will format our new partition with the FAT32 as our file system. To do that we will enter: format
fs=fat32 quick.
Figure 10 - Format
Now, we need to mark our new partition as active. To do that we will enter: active.
Figure 11 - Active
Now we have a USB drive with an active partition. To use it as the installation source we also have to make it
bootable. As we will see, we will run the bootsect command to copy the boot manager information that
Windows 7 requires to perform the install, to our USB drive. Then we will have to copy the entire content of
the Windows 7 DVD to the USB drive. To do all that, first we need to exit from Diskpart. In CMD enter: exit.
6
Basics
Creating a Windows 7 USB Installation Source
Figure 12 - Exit
In our example, Windows 7 installation DVD is in the D drive. In the D drive, in the folder called 'Boot', there
is a program called 'bootsect'. We will run it with the '/NT60' parameter and we will also specify the drive
letter of our USB drive. This will copy the the boot manager files to our USB drive. The command, in our case,
looks like this: d:\boot\bootsect /NT60 e:.
Figure 13 - Bootsect
As we can see, our E drive was updated with all the necessary boot manager information that Windows 7 needs
to boot of the USB drive.
3. Copy DVD Content to USB Drive
The last step is to copy all files from the Windows 7 DVD to our USB drive.
Figure 14 - Copy Content from DVD to USB
7
Basics
Creating a Windows 7 USB Installation Source
Once the copy is complete, our USB drive is ready for use. Of course, on the computer on which we want to
perform the installation, we have to go to the BIOS and make sure that the USB device is selected to boot
from. After that the installation will be the same as if we were installing from a DVD.
8
Basics
Upgrading to Windows 7 - Overview
Upgrading to Windows 7 - Overview
Before you start
Objectives: learn which Windows versions can be upgraded to Windows 7.
Prerequisites: you should know about different ways to install Windows.
Key terms: edition, version, upgrade, platform, hardware requirements
Different Editions
Edition upgrades can only be performed from a lower edition to a higher edition. It can be performed using
installation media or using the Windows Anytime Upgrade. Windows Anytime Upgrade was introduced in
Windows Vista and it allows us to purchase an edition upgrade for the operating system over the Internet.
Keep in mind that we cannot upgrade 32-bit edition to 64-bit edition of Windows and vice-verca.
Different Platforms
To change or migrate to a different platform (32-bit or 64-bit) we can use the Wipe-and-Load or Side-by-side
migration of Windows 7 or use multi boot. We will be required to migrate user data and application settings
between the two installations. This is not upgrade, but migration.
Previous Windows Versions
Windows 7 only supports upgrades from computers running Windows Vista with Service Pack 1 installed.
Windows XP installations cannot be upgraded to Windows 7. If we want to upgrade from Windows XP, first
we need to upgrade to Windows Vista SP 1 and then to Windows 7.
Hardware Requirements
Before upgrading we need to have at least 15 GB of free hard drive space. Windows Vista and Windows 7 in
general have the same hardware requirements. To check for hardware incompatibilities we can use Windows 7
Upgrade Advisor tool that will inform us of any device or software incompatibilities that our computer might
have. Before running Upgrade Advisor it is recommended to connect all devices to the computer, such as
printers, scanners, cameras and other devices that we will be using on Windows 7.
Recommendations
It is recommended to perform full backup of existing installation in case the upgrade fails. Also we should
ensure that we have proper product keys available for Windows or any application or game that is installed on
existing installation.
The biggest benefit in upgrading from an existing installation to Windows 7 is that the users settings and
applications are preserved.
9
Basics
Migrating to Windows 7 using WET
Migrating to Windows 7 using WET
Before you start
Objectives: learn where to find WET, how to run it and which options to use in different situations.
Prerequisites: you have to be familiar with migration terms and utilities.
Key terms: wet, migwiz, migration, user profile, example, location, transfer, account
Running Windows Easy Transfer (WET)
In Windows 7 we can run WET by going to Start > All programs > Accessories > Systems Tools >
Windows Easy Transfer. This will actually open migwiz.exe file which is located
in %windir%\system32\migwiz\ folder. We can also find migwiz.exe on every Windows 7 installation
DVD. Just browse to the [DVDdrive]\support\migwiz\ folder and search for migwiz.exe. That is our
Windows Easy Tranfer tool. We can copy migwiz folder to another location, for example, on a network share
to be easily accessible from all computers on the network.
The first thing we have to do is run WET on the source installation to gather all data. Although Vista already
has a migration tool built in, we have to use newer version of WET because we will migrate to a newer system,
which is Windows 7. The same thing is when migrating from XP. Because of that, we will use the Windows 7
installation DVD, which contains newer WET, on our Vista machine and run the migwiz.exe. We have to have
administrative rights to run WET. The following window will appear:
Figure 15 - WET Tool
10
Basics
Migrating to Windows 7 using WET
As we can see on the picture, we can use WET utility to transfer user accounts, their documents, pictures,
movies, videos etc. Notice that we can not transfer applications. On the next screen we can choose where to
save our data.
Figure 16 - How to Transfer and Location
We can use a special "type A to type A" USB cable which is also called Easy Transfer Cable. It is used to
connect two computers together. We can also transfer data over network by establishing a TCP/IP connection.
The third option is to store data on a removable media, local hard disk, network share or a mapped drive. In
our example we will select third available option. On the next screen we have to select which computer we are
using.
Figure 17 - Computer Selection
This is our old computer. It is Vista computer so we only have one option. When we select it, the tool will scan
for all available user accounts on our machine.
11
Basics
Migrating to Windows 7 using WET
Figure 18 - Available Accounts
Once the scan is complete we can see that it detected one profile (ivancic) and Shared Items. In our example
we will only select "ivancic" account and click Next. On the next screen we can set the password for the data
that will be exported.
Figure 19 - Password
In our example we will leave password empty and click Save. On the next screen we can choose where to save
our files.
12
Basics
Migrating to Windows 7 using WET
Figure 20 - Migration Location
Remember that we could easily browse to a network location and save our migration data there. That way the
data would be available for every computer on the network. In our example we will save our data on a local
hard disk, to c:\migration folder.
Figure 21 - Saving Data
13
Basics
Migrating to Windows 7 using WET
Our data will be exported with a MIG extension. Now we can copy it to a new Windows 7 computer and run it
by double clicking it or by running migwiz and then importing it.
14
Basics
Migrating to Windows 7 using USMT
Migrating to Windows 7 using USMT
Before you start
Objectives: learn where to find USMT and which commands you can use to gather user profiles from source
installation and then apply them to the destination installation. This is demo on how to use USMT to migrate user
profiles from old to new Windows installation (XP to 7 in this case). Although here you can see all steps required to do migration
completely, for more advanced usage of all USMT options you will have to read USMT documentation.
Prerequisites: you have to be familiar with migration concepts in general and with tools which you can use.
Key terms: usmt, user profile, scanstate, loadstate, command, account, cmd, syntax, source, destination
Running USMT on Source Computer
USMT is a part of Windows AIK, but it can also be downloaded from Microsoft website as a standalone
application. The thing is, since we will migrate users from XP, we have to have USMT on XP machine. There
are two ways to put USMT on XP. First would be to download UMST from Microsoft site and install it.
During te installation you can choose the installation folder, which you have to remember. The second way
implies that you have Windows AIK installed on your Windows 7 machine. USMT will be located
in C:\Program Files\Windows AIK\Tools\USMT\x86 folder (if you have x64 system you have to use x64
version) which contains all the files needed for user migration. We can copy this folder to a network share to
make it always available. For this demonstration we will simply copy USMT folder to the C: drive of our
Windows XP machine. Tools that we are going to use (scanstate and loadstate) are command line tools, so
the first thing we need to do is run Command Prompt (CMD) on our XP machine. In CMD we have to go to
our newly created USMT folder, so we will enter the command: cd c:\usmt\x86
Figure 22 - USMT Folder in CMD
Now, we want to copy all users from Windows XP to Windows 7. To do that, first we need to
run scanstate tool on the Windows XP. To check which parameters must be provided to the scanstate tool
simply enter scanstate in CMD.
15
Basics
Migrating to Windows 7 using USMT
Figure 23 - Scanstate Syntax
We can see that the syntax is: scanstate <StorePath> [Options]. In this demo we will save all data locally
in c:\usmt\users folder, so lets create a migration store by entering the following command: scanstate
c:\usmt\users. This command will gather information about all user accounts on this machine and save it in
the c:\usmt\users folder. It is possible to modify this command to select which account to include or exclude.
In our case it gathered information about 8 users.
16
Basics
Migrating to Windows 7 using USMT
Figure 24 - Scanstate Success
Destination Computer
Once the scanstate is complete we can switch to the destination computer which is Windows 7 in our case.
Now, we need to remember where we saved users from the source machine. The best thing would be to use a
network share so we can access those resources from any computer on the network. For the purpose of this
demonstration we have copied gathered user profiles which were exported to thec:\usmt\users folder on the
Windows XP machine, to the c:\usmt\users folder on the Windows 7 machine. Also, we have
copied x86folder which contains USMT, to the c:\usmt folder on Windows 7 machine. The first thing we
need to do on destination computer is to run elevated CMD. To do that, right-click CMD and select 'Run as
administrator'. Next, we need to get to the c:\usmt\x86 folder, so we will enter the command: cd
c:\usmt\x86. Next, to load users that we exported from Windows XP, we will use that loadstate tool. Let's
enterloadstate in CMD.
17
Basics
Migrating to Windows 7 using USMT
Figure 25 - Loadstate Syntax
We can see that the syntax for the loadstate command is loadstate <StorePath> [options]. To load user
accounts we will enter the command: loadstate c:\usmt\users /lac. The /lac option means that we want to
create local accounts that do not exist on our destination computer. If accounts already existed we would not
have to use the /lac switch because the information would be migrated to existing accounts. Now, because we
did not provide passwords for accounts that were migrated, they will be created as disabled. Once all accounts
are created, the migration data is copied.
18
Basics
Migrating to Windows 7 using USMT
Figure 26 - Loadstate Success
Some often used options for the scanstate and loadstate commands are:
/i - includes the specified XML-formatted configuration file to control the migration
/ui - migrates specified users data
/ue - excludes the specified users data from migration
/lac - creates a user account if the user account is local and does not exist on the destination computer
/lae - enables the user account created with the '/lac' option
/p /nocompress - generates a space-estimate file called Usmtsize.txt
Once the migration is complete we can go to the Computer Management to verify new accounts.
19
Basics
Migrating to Windows 7 using USMT
Figure 27 - New Accounts
As we can see, new accounts were created but they are disabled. Disabled accounts have an icon with an arrow
pointing down. To enable an account right-click it, go to Properties, in General tab uncheck the 'Account is
disabled' option and then click Apply.
20
Networking
Configuring IPv4 in Windows 7
Networking
Configuring IPv4 in Windows 7
Before you start
Objectives: Learn how to configure IPv4 settings on Windows 7 machine by using GUI and how to
troubleshoot connectivity in command line.
Prerequisites: you should know all about IPv4 address and about different ways to apply network settings.
Key terms: IPv4, network, address, connection, IP, settings, case, center, ping 28 - Network Center Shortcut
The Network Center will show us many options, but the one section we are particularly interested in is "Active
networks". In our case we already our network connection configured, and we are connected to the "intranet"
at our workplace.
Figure 29 - Active Networks
To see the details about that connection we can simply click its name, which is "Local Area Connection" in our
case. To see the details about that specific connection we can click on the Details button.
21
Networking
Configuring IPv4 in Windows 7
Figure 30 - Connection Details
Notice that our connection currently uses DHCP to get the required information about the network
connection. We already have our IPv4 address, subnet mask, DNS server. Notice that we can also see the
"DHCP Enabled" option which is set to "Yes", and we can also see the IP address of the DHCP server. To
change network settings we can click the Properties button. The new window will open on which we have to
select which item we want to configure. In this case we will select the "Internet Protocol Version 4
(TCP/IPv4)" protocol, since we want to change IPv4 address.
22
Networking
Configuring IPv4 in Windows 7
Figure 31 - IPv4 Selected
When we click the Properties button again, we will be able to enter new IPv4 settings. Notice that currently we
have the "Obtain an IP address automatically" option selected.
Figure 32 - IPv4 Properties
This means that our computer will use DHCP to get the connection information. To enter the information
manually we can simply select the "Use the following IP address" option. In our case we want our computer to
always use the same IP address, so we will enter 192.168.1.145 as an IPv4 address, 255.255.255.0 as the subnet
mask, 192.168.1.1 as our default gateway, and we will use the 10.10.1.2 as our DNS server. Our configuration
now looks like this.
23
Networking
Configuring IPv4 in Windows 7
Figure 33 - IPv4 Configured
To check if our connection works we should try to communicate with another host on the network. To do that
we can use the "ping" tool in command line. Let's try and communicate with the default gateway (192.168.1.1).
Figure 34 - Ping
In our case everything works fine. If we have trouble communicating with another host, we can try and ping
our own IP address, which is 192.168.1.145 in our case. If that does not work, we should try and ping the local
loopback address which is 127.0.0.1, which will check if the the IPv4 stack is properly installed. To check you
IP address and subnet mask we can use the "ipconfig /all" command. If everything seems OK, but the "ping"
action still does not work when we try to communicate with another host on the network, we should check our
firewall settings. In Windows Firewall with Advanced Security, in Inbound Rules section, we have to make
sure that "File and Printer Sharing (Echo Request - ICMPv4-In)" rule allows communication.
24
Networking
Configuring IPv6 in Windows 7
Configuring IPv6 in Windows 7
Before you start
Objectives: Learn where and how to configure IPv6 properties in Windows 7.
Prerequisites: you should know what is IPv6 and about different types of IPv6.
Key terms: IPv6, address, network, configured, center, connection, link-local, bits, details, global-id 35 - Network Center Shortcut
The Network Center will show us many options, but the one section we are particularly interested in is "Active
networks". In our case we already our network connection configured, and we are connected to the "intranet"
at our workplace.
Figure 36 - Active Networks
To see the details about that connection we can simply click its name, which is "Local Area Connection" in our
case. To see the details about that specific connection we can click on the Details button.
25
Networking
Configuring IPv6 in Windows 7
Figure 37 - Connection Details
Notice that we already have Link-local IPv6 Address configured. Link-Local address is similar to the APIPA
address in IPv4. Link-local IPv6 address always starts with "fe8". If we see a Link-local address configured on
our machine, that means that our computer was not able to contact the DHCPv6 server. To change our
network settings we can click the Properties button. The new window will open on which we have to select
which item we want to configure. In this case we will select the "Internet Protocol Version 6 (TCP/IPv6)"
protocol, since we want to change the IPv6 address.
Figure 38 - IPv6 Selected
26
Networking
Configuring IPv6 in Windows 7
By default, our computer is configured to obtained the IPv6 address automatically. In this tutorial we will try to
assign a Unique-Local IPv6 address to our host. Unique-Local addresses are similar to private addresses in
IPv4. Unique-Local address always starts with "fc" or "fd" (first 8 bits). The next 40 bits represent the "globalid", and the next 16 bits represent the "subnet-id". The remaining 64 bits represent a host. The "global-id" part
will represent our organization, while we can use the "subnet-id" to create multiple subnets. The "global-id"
part should be randomly generated, but in our case we will simply choose some random "global-id" and the
"subnet-id". So, our example Unique-Local address will be: FCAB:BEBC:ABAC:0100::1000. The default
subnet prefix length is 64.
Figure 39 - IPv6 Configured
Let's now go to the command line and check our settings by using the "ipconfig" command.
Figure 40 - ipconfig Command
Notice that now we have our IPv6 address configured, but the Link-local address also remained intact. That
means that our computer basically has two configured IPv6 addresses that can be used for communication.
27
Networking
Internet Connection Sharing (ICS) Configuration in Windows 7
Internet Connection Sharing (ICS) Configuration in Windows 7
Before you start
Objectives: Learn how to enable and configure ICS in Windows 7.
Prerequisites: you should already know what is ICS in general.
Key terms: network, computer, ICS, connection, Internet, private, enable, server, address, IP, port, settings,
Windows 7
How to Enable ICS
The computer on which we want to enable ICS has to have two network connections. One network
connection has to be connected to the public network (Internet), and another connection has to be connected
to our private network (LAN). To manage network connections on Windows 7, we can go to Control Panel >
Network and Internet > Network Connections. In our case, on our computer we have two Network
Interface Cards which provide two network connections. One connection is called "Internet", and another is
called "Local Area Connection".
Figure 41 - Connections
So, we want to share our Internet connection from this computer with other computers which are located on
our LAN. Internet connection is typically connected to a cable modem, a DSL modem, etc. Local Area
Connection is typically connected to a Switch on our local (private) network. On that Switch we will typically
have other computers connected.
28
Networking
Internet Connection Sharing (ICS) Configuration in Windows 7
Figure 42 - Example Schema
To enable ICS, we will select our Internet connection, go to its properties, and select the Sharing tab. Here we
will select the "Allow other network users to connect trough this computer's Internet connection" option. This
will basically enable ICS on this computer. In our case we will uncheck the "Allow other network users to
control or disable the shared Internet connection" option.
Figure 43 - Sharing Tab
If we click the Settings button, we will be able to control some basic firewall settings. This way we can quickly
enable some basic services that we want to be accessible from the Internet trough our ICS computer. As you
can see, when we enable ICS, our computer starts to act as a router and a NAT device.
29
Networking
Internet Connection Sharing (ICS) Configuration in Windows 7
Figure 44 - Advanced Settings
For example, let's say that we have a web server on our private network and that we want to make it publicly
accessible. The host name of the web server is "web-server". To configure this, we will select "Web Server
(HTTP)" from the list of services and click the Edit button. We will enter the name of the computer "webserver". We could also enter the IP address of the computer.
Figure 45 - Web Server Port Forwarding
Notice that other settings can't be changed (port is 80). Note that we can only do this for one computer on the
same port. This is considered port forwarding. We can add other or the same services, but they have to use
different ports. With this configured, when someone on the public network tries to access our public IP
address together with the port 80, that request fill be forwarded to the "web-server" computer on our private
network.
30
Networking
Internet Connection Sharing (ICS) Configuration in Windows 7
When the ICS is enabled, our network connections will automatically be configured with some specific settings.
First, the Local Area Connection will be configured with the 192.168.137.1 IP address. With ICS, our computer
automatically becomes the gateway for computers on our private network, and the gateway address will be the
address of the LAN interface of the ICS computer. ICS computer will also start to hand out IP addresses and
other information to computers on our private network (it will become the DHCP server). This is why it is
important that the computers on the private network are DHCP enabled. We can use commands "ipconfig
/release" and "ipconfig /renew" to obtain new configuration from the ICS server. If we see an IP address
which starts with "169.254.", this means that the computer was not able to contact the DHCP server.
31
Networking
Working With Wireless Network Connections in Windows 7
Working With Wireless Network Connections in Windows 7
Before you start
Objectives: Learn how to create Ad Hoc wireless network and how to work with infrastructure wireless
networks in Windows 7.
Prerequisites: you should have a basic understanding of wireless networks.
Key terms: network, wireless, ad hoc, connect, security, connection, option, windows 7, SSID
Ad Hoc Networks
To create an Ad Hoc wireless network we have to go to the Network and Sharing Center in Control Panel. In
the Network and Sharing Center we will click on the "Set up a new connection or network" option. On the
next window we have to select the "Set up a wireless ad hoc (computer-to-computer) network" option.
Figure 46 - Ad Hoc Network Option
The next thing we need to do is to specify the name of our network and choose the security type. For ad hoc
networks, the available security types are Open, WEP and WPA2-Personal. Remember that WPA2-Personal is
a lot more secure than WEP, so we should always use WPA2 if all devices support it. In our case we will
choose WPA2-Personal, so we also have to specify the security key.
32
Networking
Working With Wireless Network Connections in Windows 7
Figure 47 - Network Settings
The purpose of the ad hoc network is to provide temporary wireless network access for devices in close
proximity, without the need of wireless access point. On the next screen we will also be able to turn on Internet
connection sharing. This is because our computer is also connected to the wired network which has Internet
connection, so we can share that Internet connection with the clients on the ad hoc network if we want.
Figure 48 - Network Created
At this point other devices will be able to find and connect to our wireless ad hoc network. If we click on the
network icon in the System Tray, we can see that our ad hoc network is waiting for users.
33
Networking
Working With Wireless Network Connections in Windows 7
Figure 49 - Waiting for Users
Note that the icon used for ad hoc network has three computers connected in triangle, while the infrastructure
networks have bars as the icon. One other thing that we should remember about ad hoc networks is that they
will be removed once all users disconnect from it. Also, users who connect to the ad hoc network are not able
to save it in the list of wireless networks.
If we don't enable Internet connection sharing, users which connect to our ad hoc network will not get their IP
address automatically from the DHCP. If you have experience with IP addressing, you will know that in this
case the devices will automatically use some address from the APIPA range, and this will actually work. We can
also specify the IP address on every device manually (this also includes the computer on which we set up the ad
hoc network). However, if we enable Internet connection sharing in the first place, all devices will get their IP
address from the DHCP server on the computer on which we have created the ad hoc network.
Infrastructure Wireless Networks
The process of connecting to wireless networks with access points is really simple in Windows 7. We simply
click on the network icon in the System Tray, select the available wireless network and click on the Connect
button.
Figure 50 - Available Wireless Networks
34
Networking
Working With Wireless Network Connections in Windows 7
In our case we are connecting to a network which is using WPA2-Personal security standard, so we have to
provide the password to gain access to the wireless network.
Figure 51 - Network Security Key
So, when we enter the correct security key we will connect to the network, and that's it. Now, sometimes the
SSID of the wireless network is not being broadcasted. To connect to that kind of network we have to create
the wireless network profile manually. To do that we have to go to the Network and Sharing Center, and select
the "Set up a new connection or network" option. In the window we have to select the "Manually connect to a
wireless network" option.
Figure 52 - Manual Configuration
On the next screen we have to specify the SSID (network name), security type, encryption type and the security
key. We also have to select the "Connect even if the network is not broadcasting" option. This will ensure that
our computer will connect to the network which has SSID broadcasting disabled. Note that we have to know
all those settings before we start connecting.
35
Networking
Working With Wireless Network Connections in Windows 7
Figure 53 - Network Profile
Now, if we go to the Network and Sharing Center, and then select the "Manage wireless networks" option, we
will see our newly created network listed.
Figure 54 - Network Management
Here we will also see any other network that we have previously connected to. Here we can delete all those
wireless networks or modify them. Have in mind that we can't modify the SSID of the existing network here. If
the SSID is changed, we have to delete the old network and create a new one.
One other thing that we should have in mind is the Profile Type. If we click on the Profile Type button in the
"Manage wireless networks" window, we will be able to choose the type of profile to assign to new wireless
networks.
36
Networking
Working With Wireless Network Connections in Windows 7
Figure 55 - Profile Type
Have in mind that by default all wireless networks created on the computer can be used by all users. However,
we can set up the per-user profile configuration. This way users can create connections that can only be
accessed and modified by them (per-user).
Troubleshooting
The stronger wireless signal means the better wireless performance. There are several thing that we can do to
ensure proper wireless signal in our network. First, we have to ensure that all clients are in the range of our
wireless access point. To improve the range we can implement additional antennas or signal boosters in our
wireless network. Also, some physical object may cause obstructions and interference. Another option is to
install additional access points. This will increase the coverage of our wireless network.
Some devices will cause interference with our wireless network. Those devices are cordless phones,
microwaves, Bluetooth devices, or any other device with radio signal. We should move those devices away
from our AP. Also, we should always ensure that the wireless channel used in our network is not overlapping
with another channel.
Windows 7 includes many troubleshooting tools that can be used to troubleshoot wired and wireless networks.
For example, we can use a Network Diagnostics tool to diagnose the connection issues. When troubleshooting
wireless networks with this tool, the first thing we should do is try to connect to the AP, and then run the
Network Diagnostics tool.
The most common problem with wireless networks is the wrong configuration. So, the first thing we should do
is to ensure that we have configured the correct SSID and WEP/WPA keys.
37
Networking
Working with Windows Firewall in Windows 7
Working with Windows Firewall in Windows 7
Before you start
Objectives: Learn where to find and how to work with Windows Firewall in Windows 7.
Prerequisites: you should know what firewall is in general.
Key terms: firewall, Windows, network, program, allowed, configure, feature, location, service
Firewall in Windows 7
Windows 7 comes with two firewalls that work together. One is the Windows Firewall, and the other
is Windows Firewall with Advanced Security (WFAS). The main difference between them is the complexity
of the rules configuration. Windows Firewall uses simple rules that directly relate to a program or a service. The
rules in WFAS can be configured based on protocols, ports, addresses and authentication. By default, both
firewalls come with predefined set of rules that allow us to utilize network resources. This includes things like
browsing the web, receiving e-mails, etc. Other standard firewall exceptions are File and Printer
Sharing, Network Discovery, Performance Logs and Alerts, Remote Administration, Windows Remote
Management, Remote Assistance, Remote Desktop, Windows Media Player, Windows Media Player Network
Sharing Service.
With firewall in Windows 7 we can configure inbound and outbound rules. By default, all outbound traffic is
allowed, and inbound responses to that traffic are also allowed. Inbound traffic initiated from external sources
is automatically blocked.
Sometimes we will see a notification about a blocked program which is trying to access network resources. In
that case we will be able to add an exception to our firewall in order to allow traffic from the program in the
future.
Windows 7 comes with some new features when it comes to firewall. For example, "full-stealth" feature blocks
other computers from performing operating system fingerprinting. OS fingerprinting is a malicious technique
used to determine the operating system running on the host machine. Another feature is "boot-time filtering".
This features ensures that the firewall is working at the same time when the network interface becomes active,
which was not the case in previous versions of Windows.
When we first connect to some network, we are prompted to select a network location. This feature is know as
Network Location Awareness (NLA). This features enables us to assign a network profile to the connection
based on the location. Different network profiles contain different collections of firewall rules. In Windows 7,
different network profiles can be configured on different interfaces. For example, our wired interface can have
different profile than our wireless interface. There are three different network profiles available:
Public
38
Networking
Working with Windows Firewall in Windows 7
Home/Work - private network
Domain - used within a domain
We choose those locations when we connect to a network. We can always change the location in the Network
and Sharing Center, in Control Panel. The Domain profile can be automatically assigned by the NLA service
when we log on to an Active Directory domain. Note that we must have administrative rights in order to
configure firewall in Windows 7.
Configuring Windows Firewall
To open Windows Firewall we can go to Start > Control Panel > Windows Firewall.
Figure 56 - Windows Firewall
By default, Windows Firewall is enabled for both private (home or work) and public networks. It is also
configured to block all connections to programs that are not on the list of allowed programs. To configure
exceptions we can go to the menu on the left and select "Allow a program or feature through Windows
Firewall" option.
39
Networking
Working with Windows Firewall in Windows 7
Figure 57 - Exceptions
To change settings in this window we have to click the "Change settings" button. As you can see, here we have
a list of predefined programs and features that can be allowed to communicate on private or public networks.
For example, notice that the Core Networking feature is allowed on both private and public networks, while
the File and Printer Sharing is only allowed on private networks. We can also see the details of the items in the
list by selecting it and then clicking the Details button.
Figure 58 - Details
If we have a program on our computer that is not in this list, we can manually add it by clicking on the "Allow
another program" button.
40
Networking
Working with Windows Firewall in Windows 7
Figure 59 - Add a Program
Here we have to browse to the executable of our program and then click the Add button. Notice that we can
also choose location types on which this program will be allowed to communicate by clicking on the "Network
location types" button.
Figure 60 - Network Locations
Many applications will automatically configure proper exceptions in Windows Firewall when we run them. For
example, if we enable streaming from Media Player, it will automatically configure firewall settings to allow
streaming. The same thing is if we enable Remote Desktop feature from the system properties window. By
enabling Remote Desktop feature we actually create an exception in Windows Firewall.
41
Networking
Working with Windows Firewall in Windows 7
Windows Firewall can be turned off completely. To do that we can select the "Turn Windows Firewall on or
off" option from the menu on the left.
Figure 61 - Firewall Customization
Note that we can modify settings for each type of network location (private or public). Interesting thing here is
that we can block all incoming connections, including those in the list of allowed programs.
Windows Firewall is actually a Windows service. As you know, services can be stopped and started. If the
Windows Firewall service is stopped, the Windows Firewall will not work.
Figure 62 - Firewall Service
In our case the service is running. If we stop it, we will get a warning that we should turn on our Windows
Firewall.
Figure 63 - Warning
Remember that with Windows Firewall we can only configure basic firewall settings, and this is enough for
most day-to-day users. However, we can't configure exceptions based on ports in Windows Firewall any more.
For that we have to use Windows Firewall with Advanced Security, which will be covered in another article.
42
Networking
Configuring Windows Firewall with Advanced Security in Windows 7
Configuring Windows Firewall with Advanced Security in Windows 7
Before you start
Objectives: Learn how to create new rules in Windows Firewall with Advanced Security. We will create
outbound rule in this example, but the principle is the same for the inbound rules.
Prerequisites: you have to know what firewall is in general.
Key terms: rule, IP, address, firewall, port, remote, screen WFAS, example, access, option, outbound
Windows Firewall with Advanced Security (WFAS)
As you should know, with WFAS we have more granular control when compared to ordinary Windows
Firewall which is also available in Windows 7. To open WFAS, simply start entering "windows firewall" in
search and select "Windows Firewall with Advanced Security" option.
Figure 64 - Open WFAS
43
Networking
Configuring Windows Firewall with Advanced Security in Windows 7
Once we open WFAS we will see a list of rules. Rules are divided to the Inbound, Outbound and Connection
Security rules. Notice that there is a lot of predefined rules that we can use. Some of them are enabled, and
some of them are disabled. Each rule can be disabled/enabled for the different network profile (domain,
private, public). We can also see the application that the rule relates to, the action, the protocol that is used,
local and remote address, the local and remote port, allowed users and allowed computers.
Figure 65 - Rules
To restrict access to our computer we would edit the Inbound rules. To restrict users to access remote
resources, we would go to the Outbound rules section. This is what we will do in this example. For the purpose
of this demo we will block users on our local computer to access the site. So, to add
a new rule, we can right-click on the Outbound rules section, all click on the New Rule option from the menu
on the right side of the window.
Figure 66 - New Rule Option
44
Networking
Configuring Windows Firewall with Advanced Security in Windows 7
On the first screen we can choose to create rules based on programs, ports or use a predefined rule. We can
also create a custom rule, which we will do in our example.
Figure 67 - Custom Rule Option
On the next screen we can specify if this rule applies to all programs or only to a specific program. For
example, here we could choose only specific Web Browsers. We could also apply this rule to specific services
only. For the purpose of this demo we will choose the "All programs" option and click Next.
Figure 68 - Programs
On the next screen we have to choose the right protocols and ports. For this, you have to know about different
networking protocols and their specific ports. For example, to access web sites our Web Browsers use HTTP
protocol. HTTP protocol uses TCP transport layer protocol, on port 80 by default. When configuring the
Outbound rule, it is more important to configure the Remote port. The local port is actually auto-generated
when the connection gets established, and it is used as a return path. Because of that, we don't have to enter it
here. The remote port is the port we are connecting to. For the remote port we will use the specific port 80.
45
Networking
Configuring Windows Firewall with Advanced Security in Windows 7
Figure 69 - Protocols
On the next screen we have to choose the IP addresses that this rule applies to. For the local IP address we can
choose the "Any IP address" option or choose to enter specific IP address. In this case this is not important
since this rule will only be applied to the local machine. However, if we were to configure this rule trough
Group Policy and push it down to our machines, we would then have to specify the specific IP addresses that
this rule should be applied to.
Figure 70 - IP Address
46
Networking
Configuring Windows Firewall with Advanced Security in Windows 7
If we click on the Customize button we can also select which interfaces this rule applies to. By default it will be
applied to all interfaces, but we can choose to only apply it to wired or wireless interfaces, or to remote access
sessions.
Figure 71 - Interface Types
The important thing to configure is the remote IP addresses to which this rule applies to. So, we have to know
the IP address of the site. To get the IP address we will try and PING it in the
command line.
Figure 72 - Ping
We got the reply and now we know that the IP address is 192.232.223.73. Let's click on the Add button and
enter the IP address.
47
Networking
Configuring Windows Firewall with Advanced Security in Windows 7
Figure 73 - IP Address Specified
Notice that in this window we can also enter the whole subnet, the range of IP addresses, or some predefined
set of computers (WINS servers, DHCP servers, DNS servers, or local subnet computers. When we click OK,
our screen now looks like this.
Figure 74 - IP Address Entered
48
Networking
Configuring Windows Firewall with Advanced Security in Windows 7
On the next screen we choose the action we want to be performed for this rule. In our case we will block the
connection.
Figure 75 - Action
On the next screen we have to choose the network profile that this rule applies to. The default is all profiles.
Figure 76 - Profile
On the next screen we enter the name of our rule and a brief description.
Figure 77 - Name
When we click Finish, we will see our new rule in the list.
49
Networking
Configuring Windows Firewall with Advanced Security in Windows 7
Figure 78 - Rule Created
When we try to browse to the now, we will see something like this.
Figure 79 - Site Blocked
Bigger organizations often use multiple IP addresses assigned to multiple servers which all serve the same web
site. For example, facebook.com uses several ranges of IP addresses, and in order to block facebook.com we
have to enter all those IP addresses (or ranges) in our outbound firewall rule in order to block access to
Facebook, for example.
50
Networking
Configuring BranchCache in Windows 7
Configuring BranchCache in Windows 7
Before you start
Objectives: Learn how to enable and configure BranchCache using Group Policy or command line (netsh
command).
Prerequisites: you have to know what BranchCache is.
Key terms: BranchCache, Windows, Group Policy, command line, netsh
Prerequisites
Remember, before we can use BranchCache feature on our local computer, we have to have a BranchCache
enabled server. This means that the BranchCache feature has to be installed on the server. This can be done by
using the Add Features Wizard.
Figure 80 - Add Feature Wizard in Windows Server 2008 R2
Also, we have to go to the properties of shared folder on the server, go to the Sharing tab, click on the
Advanced Sharing button, and then click on the Caching button. We will see a window like this.
51
Networking
Configuring BranchCache in Windows 7
Figure 81 - Offline Settings for Shared Folder
Note that the Enable BranchCache option is checked.
BranchCache Configuration in Group Policy
To configure our Windows 7 machine for BranchCache, we have to run a set of commands. We can either use
Local Group Policy editor or the command line. To open Group Policy editor, we can enter gpedit.msc in
search. In Group Policy editor, we can configure policies related to BranchCache in Computer Configuration >
Administrative Tools > Network > BranchCache.
Figure 82 - BranchCache Policies
Keep in mind that if we configure BranchCache in Group Policy, we have to manually configure Windows
Firewall with Advanced Security settings. This includes Inbound and Outbound rules.
52
Networking
Configuring BranchCache in Windows 7
Figure 83 - Inbound Firewall Rules
Figure 84 - Outbound Firewall Rules
If we configure BranchCache from the command line, firewall rules will be automatically enabled for us.
BranchCache Configuration in Command Line
To configure BranchCache in command line (cmd), we will first run it as Administrator. For example, to enable
BranchCache in distributed mode we would enter the "netsh branchcache set service mode=distributed"
command.
Figure 85 - netsh branchcache Command
Notice that the firewall rules are enabled, and service start type is set to manual (which is the right type). To
check the status of BranchCache on computer we can enter the "netsh branchcache show status".
Figure 86 - BranchCache Status
We can also configure the cache size. For example, if we want to set the cache size to 10% of our disk space,
we would enter the command "netsh branchcache set cachesize size=10 percent=true".
Figure 87 - BranchCache Cache Size
53
Networking
Configuring BranchCache in Windows 7
To see the local cache usage we can enter the "netsh branchcache show localcache".
Figure 88 - BranchCache Local Cache
Notice that here we can also see the location of the cache.
54
Networking
Creating a VPN Connection in Windows 7
Creating a VPN Connection in Windows 7
Before you start
Objectives: Learn how to create VPN connection in Windows 7.
Prerequisites: you have to know what is VPN in general.
Key terms: VPN, connection, Windows 7
Creating VPN Connection
We can create a VPN connection in Network and Sharing Center in Control Panel. Here we can select the "Set
up a new connection or network option".
Figure 89 - Set up a Connection
On the next screen we have to select the "Connect to a workplace" option.
Figure 90 - Connect to a Workplace
55
Networking
Creating a VPN Connection in Windows 7
On the next screen we will select the "Use my Internet connection (VPN)".
Figure 91 - How to Connect
On the next screen we have to enter the IP address of the VPN server (or the host name which points to that
IP address). Here we can also choose the name of the connection, and if we want to use a smart cart to
authenticate, if we want to allow other people to use this connection.
Figure 92 - IP Address
On the next screen we have to enter our credentials.
56
Networking
Creating a VPN Connection in Windows 7
Figure 93 - Credentials
If everything was entered correctly, we should be able to connect to the VPN server now. When we do that, we
will be able to access resources on the remote network.
We can always change properties of our VPN connection. To do that, simply right click it and select the
Properties option.
Figure 94 - Properties
On the General tab we can change the host name or IP address.
Figure 95 - General Tab
57
Networking
Creating a VPN Connection in Windows 7
On the Options tab we can set dialing options, as well as redialing options (rediail attempts, etc.). On the
Security tab we can select the type of VPN and data encryption options.
Figure 96 - Security Tab
If we use IKEv2, our system will have the ability to reconnect automatically. However, if we select the
Automatic type, the strongest available type of VPN will be used. On the Networking tab we can choose the
version of IP protocol that is to be used (IPv4 or IPv6), and if we'll allow file and printer sharing over the VPN
connection. On the Sharing tab we can specify if we want to allow other users to connect trough this
connection. So, we can use Internet Connection Sharing feature to share a VPN connection.
58
Networking
DirectAccess Feature in Windows 7
DirectAccess Feature in Windows 7
Before you start
Objectives: Learn what is DirectAccess, why it is important, and what to consider when configuring clients to
use DirectAccess.
Prerequisites: you have to know what is VPN.
Key terms: DirectAccess, Windows 7, prerequisites
What is DirectAccess
DirectAccess is an always on connection to our remote private network, regardless of where we are. Starting
from Windows 7 and Windows Server 2008 R2, we can use DirectAccess feature. DirectAccess in Windows 7
uses IPv6 with IPsec VPN connection which is always on. DirectAccess is different from a VPN protocol.
DirectAccess connection process doesn't require user intervention or logon (it is automatic) in contrast to a
VPN solution. It starts from the moment we connect to the Internet and allows authorized users to access
corporate network file server and intranet web sites.
Since DirectAccess is automatic, we will always have access to the remote (corporate) intranet, regardless of
where we are. DirectAccess is bidirectional, which means that servers on corporate network can access remote
clients in the same fashion as if they were connected to the local network. In many VPN solutions, the client
can access the server, but the server can't access the remote client.
DirectAccess provides administrators the ability to control resources that are available to remote users and
computers. Administrators can ensure that remote clients remain up to date with antivirus definitions and
software updates. They can also apply security policies to isolate servers and hosts. Remote DirectAccess
clients can still receive software and group policy updates from the sever on the corporate network, even if the
user hasn't logged on. This allows administrators to manage and maintain remote computers like never
before. DirectAccess reduces unnecessary traffic on the corporate network by not sending traffic that is headed
for the Internet to the DirectAccess server. Intranet communications are encrypted and sent to the
DirectAccess server, and then on to the intranet. Internet communications are sent directly to the Internet
hosts without encryption and without going through the DirectAccess server.
DirectAccess Connection Methods
DirectAccess clients can connect to the internal resources by either using the Selected server access (modified
end-to-edge) or Full enterprise network access (end-to-edge) method. The connection method is configurable
using DirectAccess console or manually trough IPsec policies.
It is recommended to use IPv6 and IPsec throughout organization, upgrade our application servers to
Windows Server 2008 R2, and enable selected server access in order to provide the highest level of security. On
59
Networking
DirectAccess Feature in Windows 7
the other hand, organizations can use full enterprise network access where the IPsec session is established
between a DirectAccess client and the server.
DirectAccess Connection Process
DirectAccess client first detects if there is network connection available. Then it attempts to connect to the
intranet site that was specified in the DirectAccess configuration. Then the client connects to the DirectAccess
server using IPv6 and IPsec. In the case that a firewall or proxy server prevents the client computer from using
either 6to4 or Toredo from connecting to DirectAccess server, the client automatically attempts to connect
using the IP-HTTPS protocol, which uses an SSL (Secure Socket Layer connection) to ensure connectivity.
After that the client and server mutually authenticate using their certificates. Active Directory group
memberships are checked so that DirectAccess server can verify that the computer and user are authorized to
connect using DirectAccess. If Network Access Protection (NAP) is enabled and configured for health
validation, the DirectAccess client obtains a health certificate from a Health Registration Authority (HRA)
located on the intranet prior to connecting to the DirectAccess server. Once the client is clear to connect to the
network, the DirectAccess begins forwarding traffic from the client to the intranet.
DirectAccess Client Configuration
If a client is connected to the network using a public IPv6 address, DirectAccess will also use a public IPv6 to
connect. If a client is using a public IPv4 address, DirectAccess will use the IPv6 6to4 method to connect to
the client. If the client is using private IPv4 address behind a NAT, DirectAccess will use the IPv6 Teredo
method to connect to the client. If the client can't connect to the intranet, because they are being blocked by a
firewall, but the client still has access to the Internet, DirectAccess will use IP-HTTPS method (the least secure
form) to connect to the client.
Computers running Windows 7 Enterprise and Ultimate, that have been joined to a domain can support
DirectAccess. We can't use DirectAccess with any other edition of Windows 7, or earlier versions of Windows
(Vista or XP). When configuring a client for DirectAccess we must add the client’s domain computer account
to a special security group. We specify this security group when we are creating a DirectAccess server. Group
Policies are used to push down the DirectAccess client configuration in comparison to traditional VPN
connections where we have to manually set VPN configuration or distribute using connection manager
administration kit. Once we have added the computers account to that designated security group, we also need
to install the computer certificate to allow DirectAccess authentication. This can be done using Active
Directory Certificate Services which will enable automatic enrollment of the appropriate certificate.
When it comes to server, we have to have a DirectAccess server running on Windows Server 2008 R2 with two
network cards. Also, we have to have Active Directory environment with at least one Domain Controller (DC)
and a DNS server running Windows Server 2008 or 2008 R2. We also need to have a Public Key Infrastructure
(PKI) with Active Directory Certificate Services (ADCS). We also need IPsec policies configured and IPv6
Transition Technologies that are available for use on a DirectAccess server such as 6to4 and Teredo.
60
Networking
DirectAccess Feature in Windows 7
When we first configure DirectAccess on a server, it creates a Group Policy Object (GPO) at the domain level
and filters it for us for that specified security group that we create during the installation process. Only clients
that are members of that group get DirectAccess policies and will be able to connect to the DirectAccess
server. Through this Group Policy we can configure settings such as 6-to-4 relay server name, the IP-HTTPS
server to connect to if all other connection methods fail, and weather the Teredo is used for DirectAccess and
the Teredo server address.
We can also configure the DirectAccess from the command line using the netsh command. Have in mind that
all configurations made manually with the netsh utility will be overwritten by corresponding Group Policy
settings.
To determine if the client has made a successful DirectAccess connection, we can connect on the network
connection icon in the system tray. This will open a status of our connection which will say "Internet and
Corporate" access. In that case we know that we have successfully connected to the DirectAccess server. If the
status is "Local and Internet", we know that there is no connection to the DirectAccess server.
As we know, DirectAccess clients use certificate for authentication. If a computer doesn't have a valid
computer certificate, which should be received from ADCS, it can't connect successfully. We can verify client
certificate using the certificate snap-in.
61
Deployment
Preparing for Windows 7 Image Capture
Deployment
Preparing for Windows 7 Image Capture
Before you start
Objectives: learn what you have to do before you can capture and deploy Windows 7 images
Prerequisites: you have to understand what is automated Windows installation, what is Windows
SIM and what is Sysprep.
Key terms: image, winpe, waik, imagex, capture, reference, installation, deployment
Installing WAIK on Technician Computer
WAIK contains all the tools we will need to prepare WinPE CD which we will use to capture Windows images.
The process of installing WAIK is really simple. Just download WAIK for Windows 7 from Microsoft web
pages (it is ISO image) and burn it to a DVD (or use virtual CD/DVD ROM to open ISO). After that simply
run the Windows AIK Setup.
Figure 97 - WAIK Main Menu
Note that you should not install WAIK on the reference computer. You should install WAIK on the
Technician computer (the one on which you work as an administrator). Reference computer should be
configured for end users. When the installation is complete we can run the Deployment Tools Command
62
Deployment
Preparing for Windows 7 Image Capture
Prompt. To do that go to Start > All Programs > Microsoft Windows AIK > Deployment Tools
Command Prompt.
Figure 98 - Deployment Tools Command Prompt
Preparing the Reference Installation
A reference computer has a customized installation of Windows that you plan to duplicate onto one or more
destination computers. You can create a reference installation by using the Windows installation DVD. You
can also create an answer file which you will use during Windows installation on your reference computer. The
answer file contains all of the settings that are required for an unattended installation. Answer file can be
created using Windows SIM, which is contained in WAIK.
Creating WinPE
Now that we have WAIK installed and a reference computer prepared, we have to create a WinPE CD. WinPE
is contained in WAIK, but we have to create WinPE CD or DVD by running the 'copype' command within the
PETools folder. Once the WinPE files and folders are created we can use the 'oscdimg' utility, which is also
part of the WAIK, to create ISO image from the created WinPE files and folders. Then we can use that ISO
image to burn a bootable DVD and boot from it. Our WinPE has to contain ImageX tool which we will use to
capture and deploy Windows images. ImageX stores the image in the Windows Image file format (.wim
format). To see how to prepare WinPE read the article Create WinPE Using WAIK for Windows 7.
Capturing Windows Image
To capture image using ImageX first we must boot our computer into a Windows PE environment. The
Windows PE environment (Windows Preinstallation Environment) is a thin version of Windows 7 with limited
services. We can boot our computer into Windows PE by either using WinPE CD, DVD or USB flash drive.
Also, network PXE booting through Windows Deployment Services (WDS) will load WinPE
automatically. Once we boot into WinPE and open a command prompt, we can run ImageX with the /capture
parameter. We can set ImageX to store the captured image to a network share. If we are capturing a Windows
7 Ultimate or Enterprise, we can set ImageX to store captured image into a VHD (Virtual Hard Disk) file and
63
Deployment
Preparing for Windows 7 Image Capture
make that VHD bootable. To an example on how to capture Windows 7 installation read the article Windows 7
Image Capture Demonstration
Excluding Files
We can also exclude certain files and folders from being captured. We can do that using configuration files. The
'Wimscript.ini' file is the configuration file that ImageX will use. Withing a 'Wimscript.ini' file we have three
sections of configuration. Those sections are:
ExclusionList
ExclusionException
CompressionExclusionList
The ExclusionList section allows us to define what files and folders are to be excluded from the capture. The
ExclusionException section allows us to override the default exclusion list during the capture process. The
CompressionExclusionList allows us to define files, folders and file types that we want to exclude during the
compression process. ImageX will look for the 'Wimscript.ini' within the same folder that stores the ImageX
tool. Example of Wimscript.ini:
[ExclusionList]
ntfs.log
hiberfil.sys
pagefile.sys
"System Volume Information"
RECYCLER
Windows\CSC
[CompressionExclusionList]
*.mp3
*.zip
*.cab
\WINDOWS\inf\*.pnf
As we see in our example, our wimscript.ini has ExclusionList section. In that section we defined what files and
folders are to be excluded during the ImageX process. We also defined what files, folders and types of files are
to be excluded from compression process. In addition to manually creating an image, ImageX can help us
modify an image without extracting it and also to deploy the captured image to a target computer.
64
Deployment
Preparing for Windows 7 Image Capture
65
Deployment
Mounting and Unmounting Windows 7 Image Using ImageX and DISM
Mounting and Unmounting Windows 7 Image Using ImageX and DISM
Before folder. There we can find 'install.wim' image.
Figure 99 -
'mount'. The content of C:\images folder now looks like this:
66
Deployment
Mounting and Unmounting Windows 7 Image Using ImageX and DISM
Figure 100 -).
Mounting 'image source').
Figure 101 -
67
Deployment
Mounting and Unmounting Windows 7 Image Using ImageX and DISM
Index '5' belongs to the Windows 7 Ultimate edition. Another example is Home Premium which has index
number 3.
Figure 102 - Ultimate Edition
Figure 103 - Home Premium Edition
When we mount an image, we have to designate which image edition we want to mount. We will do that using
particular Index Number. Let's try that now. We will mount our image using the /mountrw parameter..
68
Deployment
Mounting and Unmounting Windows 7 Image Using ImageX and DISM
Figure 104 -.
Figure 105 -.
69
Deployment
Mounting and Unmounting Windows 7 Image Using ImageX and DISM
Figure 106 - Users Folder
We can add new folders and files to that image. Just for demonstration we will add new folder named 'info' and
a text file named 'Read me' inside of the mount folder. We can create our text file somewhere else on our
computer and copy it to the mount folder. We have to have administrative privileges to copy our text file to the
mount folder.
Figure 107 - parameter, the changes we
made will not be saved.
70
Deployment
Mounting and Unmounting Windows 7 Image Using ImageX and DISM
To unmount our image and save all changes we will enter the following command: imagex /unmount
c:\images\mount /commit. Also, we should exit the mount folder in Explorer before we unmount our
image.
Figure 108 - Unmounting Successful
In our command we use the /unmount parameter to unmount our image. We had to specify the location of
our mounted image, which is in our case C:\images\mount folder. Also we use the /commit parameter.
Mounting Image Using DISM
Now we will use DISM to mount the same image again. The command to mount image using DISM is: dism
/mount-wim /wimfile:C:\images\install.wim /index:5 /mountdir:C:\images\mount. The /mountwim parameter tells DISM that we want to mount existing image. With /wimfile parameter we specify which
image we want to mount. With /index parameter we specify which edition we want to mount.
With /mountdir parameter we specify where we want to mount our image.
71
Deployment
Mounting and Unmounting Windows 7 Image Using ImageX and DISM
Figure 109 - image.
Figure 110 - ImageX Cleanup Command
Now let's try to mount our image using DISM again. This time everything works as expected.
72
Deployment
Mounting and Unmounting Windows 7 Image Using ImageX and DISM
Figure 111 - Mounting Completed Successfully
Once the mounting is complete let's verify that the changes we made are still there. Let's browse to our mount
folder.
Figure 112 - Mount Folder
As we can see on the picture, our 'info' folder and 'Read me' text file are there. Now, DISM gives us a bit more
options. We can use DISM with the /get-mountedwiminfo parameter to see all mounted images.
Figure 113 - Mounted Wim Info
73
Deployment
Mounting and Unmounting Windows 7 Image Using ImageX and DISM
If we had more than one image mounted we would see them all. We can also use DISM to check the edition of
the mounted image. To do that we would enter the command: dism /image:c:\images\mount /getcurrentedition. The /image parameter specifies the mounted image we want to check, and /getcurrentedition is used to check mounted edition.
Figure 114 - Check Mounted Edition
Notice that the current edition is Ultimate. We can also use the /get-drivers parameter to see any installed
third-party drivers in the mounted image.
Figure 115 - Get Drivers
In our case there is only one third-party driver in the driver store. Using DISM we can add drivers or even
remove drivers from the image. Next, we can also use the /get-features parameter.
74
Deployment
Mounting and Unmounting Windows 7 Image Using ImageX and DISM
Figure 116 - parameter..
Figure 117 - Unmounting Completed Successfully
Image was unmounted, changes were discarded and files were closed.
75
Deployment
Creating WinPE Using WAIK for Windows 7
Creating WinPE Using WAIK for Windows 7
Before you start
Objectives: learn how to create WinPE CD which includes ImageX, by using WAIK for Windows 7, so you
can capture and deploy Windows 7 images.
Prerequisites: you have to have WAIK tools installed on your system. You also have to know how to mount
and unmount images using ImageX.
Key terms: image, winpe, iso, imagex, mount, deployment, cmd, oscdimg
Running Deployment Tools CMD
As you already know, we have to have WAIK installed on our system. WAIK contains Deployment Tools
CMD which we will use to create our WinPE ISO. To run Deployment Tools CMD go to Start > All
Programs > Microsoft Windows AIK > Deployment Tools Command Prompt.
Creating WinPE ISO
Deployment Tools Command Prompt will automatically take us to the PETools folder. Here we will run
'copype' command, and specify 32bit system (with x86), and specify a folder where our WinPE will be saved
(in our case C:\wpe). The command looks like this: 'copype x86 c:\wpe'.
Figure 118 - copype Finished Successfully
76
Deployment
Creating WinPE Using WAIK for Windows 7
Once the files are copied we are automatically transferred to the c:\wpe folder. Let's see the content of that
folder using the 'dir' command.
Figure 119 - wpe Folder Content
In our C:\wpe folder we see that we have ISO folder, which is the folder that we will burn to an image. Also
we have default winpe.wimfile, and we have etfsboot.com file (which is boot manager).
The next step is to open wimpe.wim image file and copy files that we want into that image. The main thing
that we want to copy to winpe.wim is the ImageX tool. To do that we will open second command prompt
with elevated privileges (right-click CMD, then select 'Run as administrator'). In that second CMD we will go to
the 'c:\program files\windows aik\tools\' folder. Use the 'dir' command to check the content of that
folder. What we need to do next is use the ImageX command to mount the c:\wpe folder. Before we do that
we have to create a folder to mount it to. In our case we will create c:\wpem folder.
Figure 120 - wpem Folder Created
ImageX for 32bit systems is located in the 'x86' folder, so we will open it. Next, we will use ImageX command
with /mountrw switch. /mountrw will make our mount readable and writable. We will also choose
our winpe.wim file, boot the first installation in it (option 1), and choose our output folder (c:\wpem). The
final command looks like this: 'imagex /mountrw c:\wpe\winpe.wim 1 c:\wpem'.
77
Deployment
Creating WinPE Using WAIK for Windows 7
Figure 121 - Mounting Process
The content from the c:\wpe folder was mounted to the c:\wpem folder. When the mount is complete we
can browse to the c:\wpem folder and see the content of the image.
Figure 122 - wpem Folder
Now we have to copy ImageX from the 'C:\Program Files\Windows AIK\Tools\x86' folder to our
'c:\wpem' folder.
Figure 123 - ImageX Copied
Now we can unmount the image and commit changes. Remember that we can also copy other data, tools,
drivers or anything else that we want to have available once we boot up with that WinPE image. To unmount
the image let's go to the command prompt and run the following command: 'imagex /unmount /commit
c:\wpem'.
78
Deployment
Creating WinPE Using WAIK for Windows 7
Figure 124 - Committing Changes and Unmounting
What really happened is that the content of the c:\wpem folder (mount) was saved to the windows image.
Image was then unmounted and saved to the winpe.wim file.
Next, we are going to copy c:\wpe\winpe.wim file to the c:\wpe\ISO\sources folder and change the name
to boot.wim. We can do this using Windows Explorer. The 'sources' folder of every Windows 7 installation
contains two important files: install.wim and boot.wim. The boot.wim is for booting the DVD and starting
the installation. Install.wim stores the actuall installation files. At this poing we can create ISO image from our
prepared folder. The WAIK has a tool called oscdimg (Operating System CD Image) creator which we can
use to create ISO images from data on our hard drive. Let's go back to Deployment Tools Command Prompt
and run the oscdimg command. We will specify -n for long file names, specify the source folder,
specify destination file, and also specify the boot files which will be included in the boot sector (-b), so that
our image will be bootable. The whole command is: 'oscdimg -n c:\wpe\iso c:\wpe\winpe.iso b"c:\wpe\etfsboot.com'.
Figure 125 - oscdimg Complete
Once the ISO image is complete we can burn it to a CD or DVD, which we can then use to boot our
computer from.
79
Deployment
Windows 7 Image Capture Demonstration
Windows 7 Image Capture Demonstration
Before you start
Objectives: learn how to capture Windows 7 image using ImageX tool.
Prerequisites: we have to have WinPE media prepared, which includes ImageX tool which we will use to
capture Windows image. Our reference computer should already be installed and ready to be captured.
Key terms: image, sysprep, capture, partition, imagex, winpe, diskpart, reference
Preparing the Reference System (Sysprep)
Before we capture our reference computer image, we should run Sysprep tool on it. Sysprep.exe prepares the
Windows image for capture by cleaning up various user and computer specific settings, as well as log files. Let's
say that in our case the reference installation is complete and ready to be imaged. Now we will use
the sysprep command with the /generalize option to remove hardware-specific information from the
Windows installation, and the /oobe option to configure the computer to boot to Windows Welcome upon
the next restart. You can run the Sysprep tool from a command prompt by typing:
'c:\windows\system32\sysprep\sysprep.exe /oobe /generalize /shutdownIn'. Alternatively, if we run
the Sysprep GUI in audit mode, we can use these options:
Enter System Out Of Box Experience (OOBE) (from the System Cleanup Action list)
Check the Generalize option
Shutdown (from the Shutdown Options list)
Click OK
Runnin WinPE
Our referenced computer is now prepared and turned off. Now we need to boot that computer using WInPE
CD which we created earlier. WinPE runs from the command line. It boots the system with a limited version
of Windows 7, which provides disk access and limited networking support. It has two different architectures: a
32-bit version and a 64-bit version. The version must match the intended installation version of Windows 7.
Once we enter WinPE we can go to the root folder so that we can run ImageX which we copied earlier.
80
Deployment
Windows 7 Image Capture Demonstration
Figure 126 - WinPE Root Folder
In WinPE we have access to our network. This is great because we can transfer images to the shared folder on
our network. In our case we have a shared folder named 'shared-images' on computer named 'nx7300'. We will
map a network drive to our shared folder using a net use command: 'net use z: \\nx7300\shared-images'.
Figure 127 - Net Use Command
Our shared folder is password protected, so we have to provide our credentials. Notice that we had to provide
the computer name in front of our user name. If we had a domain account, we would provide a domain name
instead of computer name.
Figure 128 - Net Use Completed Successfully
The shared folder is now mounted as our Z drive. Before we use ImageX command we have to see on which
partition our Windows 7 installation is on. To do that we can use diskpart command.
81
Deployment
Windows 7 Image Capture Demonstration
Figure 129 - Diskpart Command
Once in diskpart we can use a 'list disk' command.
Figure 130 - List Disk Command
In our case we only have one disk. Let's select it and list partitions on that disk. To select it enter the 'select
disk 0' command.
Figure 131 - Selected Disk
To list partitions on disk enter the 'list partition' command.
Figure 132 - List Partition Command
We do that because we might have multiple disks with multiple boot partitions. We have to capture the proper
image. In our case we only have one partition. In Windows 7, if we use BitLocker, we will always have at least
two partitions when looking disks with diskpart. The first partition, size of 100MB would be BitLocker
partition. Letters for partitions in WinPE can be different from those in regular Windows 7. While running
Windows PE on a machine with BitLocker, the first logical partition is already used as drive C: (i.e., Partition 1)
and does not contain the reference computer's Windows 7 installation. We can always check the content of our
partitions.
82
Deployment
Windows 7 Image Capture Demonstration
Figure 133 - Check Partition Content
Let's go back to our WinPE disk (x: drive) and run the ImageX command to capture our Windows 7 image.
ImageX is a command line tool that creates an image from a reference computer. We will use the command
'imagex /capture c: z:\win7.wim "Win7 Image" /compress fast /verify'. The /capture means that we
are capturing Windows image, c: is the drive we are capturing, z:\win7.wim will be the exported file on the z:
drive that we mapped to, "Win7 Image" will be the image name, /compress fast will perform fast
compression, and we will also verify the image (/verify switch).
Figure 134 - ImageX Command
Figure 135 - ImageX Scanning...
83
Deployment
Windows 7 Image Capture Demonstration
ImageX will first scan all files that are on our C: partition and then create an image out of all that files. Once
the process is complete we will have win7.wim file which we can deploy to other computers, or which we can
use to perform recovery if our computer brakes down. If we intend to transfer that image to different
computer, we must run Sysprep on the reference computer before we capture the image.
84
Deployment
Windows 7 Image Deployment Demonstration
Windows 7 Image Deployment Demonstration
Beforeing.
Figure 136 - Contetn of WinPE Media
Notice that the imagex.exe is available in the X:\ directory.
Preparingcommand.
85
Deployment
Windows 7 Image Deployment Demonstration
Figure 137 -.
Figure 138 -.
86
Deployment
Windows 7 Image Deployment Demonstration
Figure 139 -.
Figure 140 - Create Main Partition
Notice that now we have second partition which is 39 GB in size. Next, we will select that new partition,
format it using NTFS, assign a drive letter to it and make it active. After that we can exit Diskpart.
87
Deployment
Windows 7 Image Deployment Demonstration
Figure 141 - Set Up New Partition
Connecting to a Network Share
In our case we have put our prepared Windows 7 image on a network share so we have to connect to it before
we can use prepared image. We have our share available on 'nx7300' computer. The share name is 'sharedimages'..
Figure 142 - Net Use Command
Network share is now available as Z drive. Let's see its content.
88
Deployment
Windows 7 Image Deployment Demonstration
Figure 143 - Z Drive Content
Notice that we have win7.wim file available here. That is the Windows 7 image that we created earlier
ourselves in our case.
Using ImageX to Apply Image
Now we can use ImageX tool on which is available on the Windows PE medium to copy and apply the premade:\'.
Figure 144 -
89
Deployment
Windows 7 Image Deployment Demonstration
similar to the Boot.ini file in previous Windows versions. In our case the command will be
'd:\windows\system32\bcdboot d:\windows'.
Figure 145 - BCDBoot Command
90
Deployment
Managing Existing Windows 7 Images
Managing Existing Windows 7 Images
Before you start
Objectives: learn which options you can use when servicing existing images using DISM.
Prerequisites: no prerequisites.
Key terms: image, dism, information, driver, wim, imagex, command, offline, options, detailed, edition,
commit, manage, mounts
Facts
Image servicing begins by mounting a previously captured image, which makes the contents of the image
accessible to be viewed or modified. Mounting an image does not start the operating system in the file.
Mounting an image as read-only lets us view the image, but not make changes. To save changes made to a
mounted image back to the original image, we must commit the changes before dismounting the image. An
online image is the operating system currently running on a computer; whereas, an offline image is a WIM file.
DISM Tool
Imagine how much time would it take us to deploy the the existing image to the computer, make necessary
changes and recapture the new image... To overcome this problem we need a method to update and service our
images offline and without booting them up. Windows 7 introduces a Deployment Image Servicing and
Management (DISM) tool. DISM is a command line tool which is used to manage existing Windows images.
DISM is part of the Windows Automated Installation Kit (Windows AIK). We can use DISM to install
updates, drivers and language packs, to enable or disable Windows features, to perform intra-edition upgrades,
and to customize international settings. With DSIM we can service different platform types, such as 32bit and
64bit. That means that we can service a 64bit image on a 32bit computer. In addition to servicing offline
images, the DISM tool can work with the installation image that is currently online (running Windows). When
we work with an online image, we generally gather information rather than make changes to the image. Any
option used on the online image can be used with the offline image as well. However, not all 'get' options are
available on the online image (for example, get-apps). If we run get-apps on the offline image, we will get info
on all MSI applications on the image. With this tool we can only service existing system images. We cannot
capture a new image. DISM is backwards compatible with older tools in the Windows Vista Automated Installation Toolkit.
Additionally, DISM works with limited functionality on a Windows Vista SP1 image.
Mounting Images
Before we can service existing image with DISM, we have to mount or apply the image. The DISM /mountwim option mounts the wim file to the directory specified by the mount directory option. If there is more than
one image in the wim file we can use the index option to specify which one we want to mount. We can also
mount an image as read-only by using the /readonly parameter.
91
Deployment
Managing Existing Windows 7 Images
In addition to using DISM, we can use ImageX to mount and unmount images as well. We can use the /mount
option with ImageX to mount image in read-only format to a specified folder. If our wim file has more than
one image we can use the index number of the image to mount that specific image. If we also want to be able
to write to that image we can mount our image using the /mountrw option. Once we have mounted our image
using ImageX and we're done working with it, we can use the /unmount option which will unmount the image
from the specified folder. We can also use the /info option to display information of our wim file with the use
of ImageX. With the use of ImageX and DISM we can take our existing images and update, manipulate and
continue to maintain them without the need of re-creating new images from scratch.
We have a separate article which describes mounting images using ImageX or DISM tool in detail: Mount and
Unmount Windows 7 Image Using ImageX and DISM.
Drivers
We can gather information on existing drivers on the image. We can also add new drivers or remove existing
ones. DISM can only manage drivers in a form of INF files. DISM does not support drivers in the form of
MSI packages or EXE files. It is recommended to place our drivers in a convenient location and properly name
the folders to easier identify them.
DISM has the capability to add a single driver using the /add-driver parameter, and by specifying exact file
name. We can also add multiple drivers by specifying the folder in which they are located. We can also add all
drivers in subfolders of the parent folder if we use the /recurse parameter. If we want to add drivers that are
unsigned, we can use the /forceunsigned option.
DISM can only remove third-party drivers. We can not remove default built-in drivers in a Windows 7 image.
All third party drivers are renamed in a form of OEM[number].inf, for example OEM11.inf. We can use
the /get-drivers option to find the driver we are looking for and then remove it using the /removedriver option.
Apps
With DISM we can gather information about Windows Installer or MSI applications, and application patches
(MSP files). We can only gather this information from an offline image. Online image does not support
application servicing. We can use the /get-apppatchesoption to list of the application patches in MSI
installations that are available in our image. We can also use the GUID of the application to display
information relevant to only that specific application. The /check-apppatch parameter will show us specific
information about the MSP patches installed in the offline image. We would use the /patchlocation to specify
the path of the MSP patch to gather information about specific MSP file. To gather information about all MSP
patches installed on our image we can use the /get-apppatchinfo parameter. Using the /get-appinfo and
the /productcode parameter we can gather detailed information about a specific MSI application installed on
the image. If the /productcode option is not used, the /get-appinfo returns detailed information about all MSI
92
Deployment
Managing Existing Windows 7 Images
applications. The /get-appsparameter displays all MSI applications installed on the image as well as the GUID
for each of them. Then we can take advantage of the GUID option to check specific information when using
other parameters.
Have in mind that /get-apppatches and /get-apppatchinfo options only work for MSP patches. The /getappinfo and the /get-appsoptions only work for MSI installations. DISM cannot be used to obtain
information from EXE, DLL or batch files. Additionally, DISM tool cannot be used to apply and install
patches or MSI applications to an offline image. The Microsoft Deployment Toolkit (MDT 2010) can be used
instead to install applications to an offline image.
Patches
In addition to adding drivers and gathering information about installed applications, DISM can be used to
apply operating system packages and patches. One of the greatest challenges when working with images is to
keep our images updated with the latest security and operating system patches. The most straight forward way
to accomplish this is to boot the image, visit Microsoft updates, install necessary patches and recapture the
image. This method is time-consuming and requires that we 'sysprep' the system again. The easiest way to
update our images is to use DISM. The DISM package servicing options can be used with the mounted offline
image to add, remove or update windows packages provided in the cabinet (CAB) files. We can also use the
package servicing options to install, update or remove Windows update stand-alone installers or MSU files.
Features
DISM can also be used to enable or disable Windows features on both offline mounted images and online
Windows installations. Have in mind that DISM commands are not case-sensitive, however, feature or patch
names are case-sensitive.
For example, the /get-packages command will display basic information about all packages on the mounted
image. We can also use the/add-package parameter to install packages on to the system. The package must be
in a form of MSU file. We can use the /remove-package option to remove existing package from the image.
The /get-featureinfo and /enable-feature option can be used to gather information about installed features
on the image, and then enable feature on that image as well. We can use /disable-feature to remove feature
from the image.
International Settings
We can use the /get-intl which returns information about the international settings and languages on an online
image. This is the only option which can be used on the online image. We can also use other parameters such
as /set-timezone to change the time zone on offline image.
Editions
Using DISM we can list editions that are stored on an image. We can also change the current edition to a
higher edition. When we perform an intra-edition upgrade to an offline image, we do not require product key.
93
Deployment
Managing Existing Windows 7 Images
We can use options such as /get-currentedition,/set-edition or /set-productkey to perform intra-edition
upgrade.
WindowsPE
In addition to the servicing options mentioned, we can also use DISM to service WindowsPE image. DISM
enables us to prepare WindowsPE image, list packages or even enable logging. We also have the ability to
associate the Unattended.XML answer file to the mounted image.
Committing Changes
After making changes to the mounted image, we must commit the changes so that they are saved to the mount
directory before dismounting the image. We can use the /commit-wim parameter to commit the changes to
the folder.
Other DISM Options
The /remount-wim option will remount the image if the mount directory is lost or orphaned. The /cleanupwim option cleans up any previously used mounts. If we mount and dismount a lot of images on a daily basis
we might want to run the cleanup option since we may receive errors from leftover resources from the
previous mounts.
The /get-wiminfo option displays information about the images within a win file. If we use the index option,
it will return information about the specific image specified by the index number.
Completion
After completing our work with the mounted image, we have to commit the changes and use the /unmountwim parameter to dismount and close the image file. To commit changes we can use the /commitwim parameter, or use the /unmount-wim together with /commitparameter. This way the changes are
saved.
Advanced DISM Options - Quick Reference
DISM command options that are frequently used are:
/wimfile - specifies the location of the WIM file
/mountdir - specifies the local directory in which to mount the WIM file
/index - specifies the edition if there is more than one edition within a WIM file
/readonly - mounts the WIM file as read only
/commit-wim - saves the changes to the WIM file
/remount-wim - remounts the WIM file if the mount directory is lost or orphaned
/cleanup-wim - cleans up any previously used resources from the previous mounts
/get-wiminfo - displays information about the editions within a WIM file
94
Deployment
Managing Existing Windows 7 Images
/get-mountedwiminfo - lists all the currently-mounted images and information about each image,
such as the mounted path, index, location and read/write permissions
/unmount-wim - dismounts the WIM file
/unmount-wim /discard - reverts all changes made since the last changes were committed and
dismounts the WIM file
/apply-unattend - applies an unattended answer file to an image
We can use the following DISM command options to manage the system image drivers:
/add-driver - adds the driver to the specified image
/add-driver /driver - adds all of the drivers in the directory
/add-driver /driver /recurse - adds all of the drivers in the directory and its subdirectories
/get-drivers - displays basic information about all out-of-box drivers
/get-drivers /all - displays basic information about all drivers, in addition to the all out-of-box
drivers
/get-driverinfo - displays detailed information about a specific driver package
/remove-driver - removes third-party drivers
/forceunsigned - overrides the digital signature requirements for drivers on 64-bit versions of
Windows 7
The driver path must use the driver's published name. Use /get-drivers /all to view the published name. We
cannot remove default drivers. Place your drivers in a convenient location before using DISM to update the
system image drivers. DISM does not support drivers in the form of .msi packages or .exe files. If adding
multiple drivers in the same command, the drivers are installed in the order that they are listed in the
command.
We can use the following DISM command options to manage Windows applications (.msi) and application
patches (.msp files):
/get-apppatches - displays a list of MSP files that are available on the image
/check-apppatch /patchlocation - displays information only if the MSP patches are applicable to
the offline image
/get-apppatchinfo - displays detailed information about all installed MSP patches
/get-appinfo - displays detailed information for all the installed MSI applications
/get-appinfo/productcode - displays detailed information about the specific MSI application
installed on the image
/get-apps - displays all MSI applications installed on the offline image as well as the GUID
95
Deployment
Managing Existing Windows 7 Images
DISM does not retrieve information from .exe or .dll files. The DISM command does not have an /add-apps
option to install applications; use Microsoft Deployment toolkit to install applications to a previously-captured
offline image.
We can use the following dism command options to manage Windows packages provided in a cabinet (.cab) or
Windows Update Stand-alone Installer (.msu) file format:
/get-packages - displays basic information about all the packages that have been installed on the
image
/get-packageinfo /packagename - displays detailed information about a specific .cab package
/get-packageinfo /packagepath - displays detailed information about a specific package
/add-package /packagepath - installs a specific .cab or .msu package to the image, including:
a single .cab or .msu file, a folder containing a single expanded .cab file, a folder containing a single
.msu file and a folder containing multiple .cab or .msu files
/remove-package - removes a .cab installed package
/get-features - displays information about all the features in a package
/get-featureinfo - displays detailed information about the feature
/enable-feature - enables a specific feature on the image
/disable-feature - disables a specific feature on the image
DISM commands are not case-sensitive; however, feature names are case-sensitive. We cannot remove .msu
installations.
We can use the following DISM command options to manage international settings for an offline or online
image:
/get-intl - returns information about the international settings and languages on an online image
/set-uilang - installs a new language on the image
/set-inputlocale - adds a new keyboard layout to the image
/set-timezone - changes the time zone of the mounted offline image
The Windows 7 installation media has a pre-staged package for each Windows 7 edition. This is referred to as
an edition-family image. We can use the following DISM command options to manage and configure the
Windows editions on an offline or online image:
/get-currentedition - identifies the edition of the offline or online image
/set-edition - upgrades the Windows image to a higher edition
/set-productkey - enters the product key for the current edition in an offline Windows image after
you change an offline Windows image to a higher edition.
96
Deployment
Managing Existing Windows 7 Images
The following options revert all pending actions from the previous servicing operations because the actions
might be the cause of a boot failure:
/cleanup-image
/revertpendingactions
ImageX Quick Reference
ImageX is primarily used to capture a Windows 7 installation onto a network share, but it can also mount an
image so that it can be modified. After the image is modified, we can use ImageX to capture the image, append
the image to a WIM file, or export the image as a separate file. If we do not need to capture, append, or export
the image after we modify it, we should use DISM to mount the image instead of using ImageX.
Common ImageX command options are:
/mount - mounts a Read-Only version of the image file to the specified directory
/mountrw - mounts a Read-Write version of the image file
/unmount - dismounts the image file
/commit - saves the changes to the image while dismounting
/info - displays detailed information about the image file
/export - deletes unnecessary resources from the image file, reducing its size
/append - appends files to the image. Appended image files must use the same compression type as
the initial capture
Examples
We have an article on how to service existing images and on how to apply updates to existing image, so be sure
to check them out if you want to see a demo on how to work with images using DISM.
97
Deployment
Servicing Windows 7 Image Using DISM
Servicing Windows 7 Image Using DISM
Before you start
Objectives: learn how to use DISM to service existing Windows 7 image.
Prerequisites: you have to have WAIK installed. You also have to know what DISM is.
Key terms: image, mount, dism, command, feature, driver, parameter, folder
Image
For the purpose of this demo, we will be working on image which we will get from the Windows 7 installation
DVD. In our case we have copied install.wim image from the Windows 7 installation DVD ([DVD
drive]:\sources\install.wim) to the C:\images\ folder. In that folder we have also created the 'mount'
folder which we will use to mount our image.
Figure 146 - Folders
Next we need to open Deployment Tools Command Prompt with elevated privileges. To do that go to Start >
All Programs > Microsoft Windows AIK > Deployment Tools Command Prompt (Deployment Tools
Command Prompt comes with WAIK for Windows 7).
Mounting
Next we will mount our image. To do that we will enter the following command: dism /mount-wim
/wimfile:c:\images\install.wim /index:5 /mountdir:c:\images\mount. 'DISM' means that we are using
DISM to mount our image. /mount-wim parameter means that we want to mount existing image.
With /wimfile parameter we specify the location of our image. With /index parameter we specify which
edition we want to mount (Ultimate in our case). With /mountdir parameter we specify where do we want to
mount our image.
98
Deployment
Servicing Windows 7 Image Using DISM
Figure 147 - Mounting in Progress
Working with Features
Once our image is mounted we will check features that are available on our mounted image. To do that we will
use the following command: dism /image:c:\images\mount /get-features. The /image parameter is used
to specify the location of our mounted image. The/get-features parameter is used to check for available
features.
Figure 148 - Available Features List
Different editions of Windows will have different features available. Among other things we have a feature that
is called Minesweeper. This is a game that is available for free in Windows and it is currently enabled. Let's
gather more information about that feature. We will use the following command: dism
/image:c:\images\mount /get-featureinfo /featurename:Minesweeper. Remember that feature names
are case-sensitive.
99
Deployment
Servicing Windows 7 Image Using DISM
Figure 149 - Minesweeper Feature
Now we will disable that feature. To do that we will enter the following command: dism
/image:c:\images\mount /disable-feature /featurename:Minesweeper.
Figure 150 - Feature Disabled
If we want to enable some feature we can use the /enable-feature option. In our case Minesweeper is disabled
on our mounted image so it will not be available by default once we install our Windows 7 Ultimate edition.
We can run the dism /image:c:\images\mount /get-features command to check for available features
again. Notice that the status of the Minesweeper feature is now 'Disable Pending'.
100
Deployment
Servicing Windows 7 Image Using DISM
Figure 151 - Feature Status
Changing the Time Zone
We will change our time zone to the Central European Standard Time. To set the time zone we will use the
following command: dism /image:c:\images\mount /set-timezone:"Central European Standard
Time". For a complete list of time-zone strings see the Unattend Setup Reference or use the tzutil command
with the '/l' parameter on a running Windows 7 machine.
Figure 152 - TZUTIL
101
Deployment
Servicing Windows 7 Image Using DISM
Figure 153 - Time Zone Changed
Adding Drivers
We have added a new folder called 'addons' to the C:\images\ folder. Here we have copied the driver that we
want to add to the image driver store. In our case we want to add drivers for Samsung ML1640 printer.
Figure 154 - Samsung Drivers
To add our driver we will run the following command: dism /image:c:\images\mount /adddriver:"C:\images\addons\SamsungML1640\ssp2m.inf". Notice when specifying the path to our drivers,
we also specified the Setup Information file (.inf extension). In our case that file is ssp2m.inf.
102
Deployment
Servicing Windows 7 Image Using DISM
Figure 155 - Driver Installed
Driver content has been copied to the driver store successfully. If we enter the command dism
/image:c:\images\mount /get-drivers, we can see all third party drivers installed in our image.
Figure 156 - List of Drivers
Notice that our new driver now has a published name: oem1.inf. Below that we can see the original file name
(sspm.inf), class name (Printer), provider name (Samsung), date and version.
Unmounting Image
We have made all changes that we wanted so we are ready to unmount our image. To do that we will enter the
following command: dism /unmount-wim /mountdir:c:\images\mount /commit. Be sure to exit folder
that is used for mounting in Explorer.
103
Deployment
Servicing Windows 7 Image Using DISM
Figure 157 - Unmounting Successful
Notice the /commit parameter. It is used to save all changes that we made to our image. If we don't want to
save changes can use the/discard parameter.
104
Deployment
Applying Updates to Windows 7 Image Using DISM
Applying Updates to Windows 7 Image Using DISM
Before you start
Objectives: demonstration on how to use DISM to update existing Windows 7 image.
Prerequisites: you have to have WAIK installed. You also have to know what DISM is.
Key terms: image, mount, dism, install, package, command, deployment, update, msu, mount
Image
In our case we will be working on the default Windows 7 image that we have copied from Windows 7 DVD,
called install.wim. It is located in the [DVD drive]:\sources\ folder, and we will copy it to
our c:\images\ folder. We also have c:\images\mount\ folder which we will use to mount our image. We
have also installed The Windows Automated Installation Kit (WAIK) for Windows 7. This is necessary because
we need to use the DISM command line tool. So, the first thing we will do is run Deployment Tools
Command Prompt with elevated privileges. To do that go to Start > All Programs > Microsoft Windows
AIK > Deployment Tools Command Prompt (right-click > Run as administrator).
Mounting Image
We have to mount our install.wim image so we can work on it in offline mode. To mount our image we will
use the follwing command:dism /mount-wim /wimfile:c:\images\install.wim /index:4
/mountdir:c:\images\mount.
Figure 158 - Mounting Image
Current Packages
When the mounting is complete, we can see what packages does it currently contain. To do that we will enter
the following command (against our mounted image this time): dism /image:c:\images\mount /getpackages.
105
Deployment
Applying Updates to Windows 7 Image Using DISM
Figure 159 - Get-packages Command
The /get-packages option shows us all installed packages on our image. The benefit of using DISM is that we
can have an image which we can frequently update so we don't have to worry about that image becoming out
of date. This way, we don't have to install our image, then apply updates on live machine, and then capture the
new image. We can always work on our existing image which saves a lot of precious time.
We can only install packages which are in .cab or .msu format. In our case we will install an update package
that we downloaded from Microsoft website. We will put that file in c:\images\packages folder. The update
file in our case is Windows6.1-KB2533623-x86.msu.
Figure 160 - Update File
Adding Packages
To add that package we will enter the following command: dism /image:c:\images\mount /add-package
/packagepath:c:\images\packages\Windows6.1-KB2533623-x86.msu. To add packages we use
the /add-package option, but we also have to specify the package path with the /packagepath parameter.
106
Deployment
Applying Updates to Windows 7 Image Using DISM
Figure 161 - Adding Package
We can verify that our package is installed by using the dism /image:c:\images\mount /getpackages command. Our package will be last on the list because it is the newest installed package. The status
is Install Pending because the actual installation of our package will happen when the image is being applied
to the machine.
Unmounting and Saving Changes
Once we are done we can unmount our image, but we have to save our changes with the /commit option.
The whole command is: dism /unmount-wim /mountdir:c:\images\mount /commit.
Figure 162 - Unmounting
107
Deployment
Creating Virtual Hard Disk (VHD) using Disk Management in Windows 7
Creating Virtual Hard Disk (VHD) using Disk Management in Windows 7
Before you start
Objectives: learn how to create, initialize, format, attach and detach a VHD file using Disk Management tool
in Windows 7.
Prerequisites: you have to know what VHD is in general.
Key terms: disk, vhd, file, management, size, create, format, select, detach, drive, case, computer
Disk Management
The first thing that we will do is create a VHD file. To do that we can use Disk Management tool, which is
available in Control Panel > Administrative Tools > Computer Management > Disk Management. Once in
Disk Management, we will go to Actions and select the 'Create VHD' option. When we do that we will have to
select the location where we want to store our VHD, disk size, and the format of our VHD.
Figure 163 - VHD Parameters
In our case we will save our VHD file to the C: drive. The name of the VHD file is 'UserFiles.vhd'. The size of
our virtual disk will be 256 MB. Since our disk is so small we will select 'Fixed size' for our disk format. Fixed
size will create the VHD with the complete size of 256 MB, wile the 'Dynamically expanding' will create the
VHD with zero MB and will expand up to the 256 MB as we write information to it. When we click OK, the
Disk Management tool will attach our newly created VHD automatically.
Initializing and Formatting
So, now our VHD exists (Disk 1), but it’s not initialized nor formatted.
108
Deployment
Creating Virtual Hard Disk (VHD) using Disk Management in Windows 7
Figure 164 - VHD Created (Disk 1)
To initialize disk, we will right-click on Disk 1 and select the 'Initialize Disk' option.
Figure 165 - Right-click Disk 1
Here we will leave default options and click OK.
109
Deployment
Creating Virtual Hard Disk (VHD) using Disk Management in Windows 7
Figure 166 - Initialize Disk
Now we can create new volume on our VHD and specify a drive letter. To do that we will right-click on
unallocated space on our Disk 1 and select the 'New Simple Volume' option.
Figure 167 - Right-click Unallocated Space
The wizard will appear. The wizard will first ask us about the size of the volume. We will leave maximum size
in our case.
Figure 168 - Volume Size
Next, it will ask us about the drive letter. In our case ti is E.
Figure 169 - Drive Letter
110
Deployment
Creating Virtual Hard Disk (VHD) using Disk Management in Windows 7
Next, we will choose the file system and perform a format. In our case we will select NTFS as our file system
with default allocation unit size, volume label will be 'UserFiles', and we will perform a quick format.
Figure 170 - Format Partition
Once the format is complete, we can browse to our computer and see our newly created E: drive.
Figure 171 - Disks on our Computer
Everything that we do on E: drive is actually saved in UserFiles.vhd file. If we go to the C: drive, we can see the
UserFiles.vhd file which is used as our virtual disk.
Figure 172 - Files on Dick C:
We can also detach VHDs from our computer. To do that, let's go back to Disk Management, right-click our
virtual hard disk (Disk 1 in our case) and select the 'Detach VHD' option.
111
Deployment
Creating Virtual Hard Disk (VHD) using Disk Management in Windows 7
Figure 173 - Detach VHD
If we only want to detach the VHD, and don't want to delete the VHD file, we mustn't select the 'Delete the
virtual hard disk file after removing the disk' option. So, we have to be careful here if we want to use the VHD
file on another computer.
Video Tutorial
We also have a video tutorial on how to create and manage VHD using Disk Management.
112
Deployment
Creating Virtual Hard Disk (VHD) using Diskpart in Windows 7
Creating Virtual Hard Disk (VHD) using Diskpart in Windows 7
Before you start
Objectives: learn how to create and manage virtual disk using Diskpart command line tool.
Prerequisites: you have to know what a virtual hard disk is.
Key terms: disk, command, create, virtual, diskpart, file, vhd, install, partition, vdisk, drive, select
Running CMD
When running CMD in this case, we have to be sure that we run it with administrative privileges. To do that,
right-click on CMD, and select 'Run as administrator' option. This will give us elevated command prompt, so
we will click on Yes when we get User Account Control prompt.
Figure 174 - Run CMD as Administrator
From the CMD we will run diskpart. To do that, simply enter "diskpart" and hit Enter.
Figure 175 - Enter Diskpart Tool
Once in Diskpart we will run the following command: "create vdisk file=c:\install1.vhd maximum=15000".
This command will create a virtual hard disk file on our C: drive, with the file name "install1.vhd", and
maximum disk size of 15000 MB. We could also add the "type=fixed" or "type=expandable" parameter, but
the default is "fixed" so we didn't write it.
Figure 176 - Create Vdisk Command
Once the VHD creation is complete we will have a install1.vhd file on our C: drive, with 15 GB in size.
113
Deployment
Creating Virtual Hard Disk (VHD) using Diskpart in Windows 7
Figure 177 - C Drive
Now we can attach our virtual disk to the system. To do that first we have to select the disk that we want to
attach. To do that we will enter the following command: "select vdisk file=c:\install1.vhd". This command
will select the install1.vhd virtual hard disk so that we can work with it.
Figure 178 - Select Command
Now that the virtual disk is selected we can run the attach command. The command is: "attach vdisk".
Figure 179 - Attach Command
Let's check the details of our selected virtual disk. To do that we will enter the command: "detail vdisk".
Figure 180 - Detail Vdisk
At this point our disk is not initialized. We can't create any partitions or volumes on this disk if we don't
initialize it. To initialize the disk we will enter the command: "convert mbr". This will convert our disk to basic
disk format with the master boot record partition style.
114
Deployment
Creating Virtual Hard Disk (VHD) using Diskpart in Windows 7
Figure 181 - Convert Command
Now we can create a partition on the disk. To do that we will use the command: "create partition primary".
We won't specify the size, so the whole unallocated space will be used to create the partition.
Figure 182 - Create Partition
Now we can format our partition. To do that we will use the command: "format fs=ntfs label="install"
quick". This command will format our partition using NTFS file system, label it as "install", and it will use
quick formatting.
Figure 183 - Format Partition
Now we can assign a drive letter to it: "assign letter=e"
Figure 184 - Drive Letter
That's it. We can now use our virtual disk and save files to it. Let's try to make a new directory in it. To do that
we will leave diskpart, and enter few commands.
Figure 185 - Working with E Drive
115
Deployment
Creating Virtual Hard Disk (VHD) using Diskpart in Windows 7
We can now browse to it using Windows Explorer.
Figure 186 - Computer
Figure 187 - E Drive
We can also detach virtual disk from our system. To do that we have to go back to diskpart and determine
which virtual disk we want to detach. In our case we want to detach install.vhd disk. First we have to select that
file: "select vdisk file="c:\install1.vhd"
Figure 188 - Select Command
At this point we can detach the disk using the command: "detach vdisk"
Figure 189 - Detach Vdisk
All this can be done using Disk Management tool in Windows 7. We have a separate article in which we
show how to create virtual disk using Disk Management.
116
Management
Advanced Driver Management in Windows 7
Management
Advanced Driver Management in Windows 7
Before you start
Objectives: Learn how to use Device Manager, how to edit Group Policy for drivers, and how to add Device
Paths using Registry Editor.
Prerequisites: you have to know what are drivers, you have to know what is Group Policy and you have to
know what is Registry and Registry Editor.
Key terms: device, driver, install, computer, policy, group, guid, option, windows, manager, audio
Device Manager
To open Device Manager, we cab right-click on Computer, select Manage, and then select Device Manager
from the menu on the left.
Figure 190 - Device Manager
Let's try and update the drivers for the Audio Controller drive on our computer. We will right-click it, and
select "Update Driver Software" option.
117
Management
Advanced Driver Management in Windows 7
Figure 191 - Update Driver Software
On the next screen we will select "Browse my computer for driver software".
Figure 192 - Browse Computer Option
On the next screen we will select the "Let me pick from a list of device drivers on my computer" option.
Figure 193 - Pick Device Option
118
Management
Advanced Driver Management in Windows 7
By default, the only drivers that will be shown to us are the compatible drivers, but we can force it to show us
the incompatible ones as well. We do that by deselecting the "Show compatible hardware" option.
Figure 194 - Compatible Drivers
Figure 195 - All Drivers
Just for the sake of this demonstration, we will try to install the "Yamaha USB Audio" driver, which was not in
the compatible hardware list.
Figure 196 - Yamaha USB Audio
When we click next, we will be warned that this driver might not work with our device. We will click Yes on
the warning.
Figure 197 - Warning
Now, we already know that this driver will not work with our device, because the manufacturer of our Audio
device is not Yamaha at all. By doing this we want to show you what happens when we install some driver
which is not compatible, or which causes errors with our device. This can happen when we try to install
119
Management
Advanced Driver Management in Windows 7
updated drivers for our devices, so we should know how to troubleshoot this kind of problem. When we install
a problematic driver, we will see an exclamation mark on that device in the Device Manager.
Figure 198 - Exclamation Mark
There are three ways in which we can troubleshoot this. If the problem with the driver is so serious that it
doesn't even allow us to even boot to regular environment, we can reboot our computer into Safe Mode, then
come to Device Manager and then do a Driver Rollback. When we reboot we can also try and go to Last
Known Good Configuration instead of Safe Mode. We do that by pressing F8 when we reboot. The Last
Known Good Configuration will basically go back to the old version of the driver. Keep in mind that Last
Known Good Configuration is overwritten every time we successfully boot to our computer. That means that
if we boot to our computer after we install the problematic driver, Last Known Good will be overwritten
together with that problematic driver. That's why it is important to remember when the problem happened and
if we have logged in after the problem happened. If we didn't log in, the Last Known Good Configuration will
probably help us to fix the issue.
To roll back the problematic driver we can right-click problematic device, go to its properties, go to the Driver
tab, and then click the Roll Back Driver button.
120
Management
Advanced Driver Management in Windows 7
Figure 199 - Driver Tab
Have in mind that we can only rollback one version of the driver. Windows remembers only the previous
driver installed. When we click on the Roll Back Driver button, it will ask us to confirm our intention and give
us a little warning.
Figure 200 - Rollback Warning
We will click Yes, and when we do that, the old driver will be restored, and our device will be working again.
121
Management
Advanced Driver Management in Windows 7
Group Policy and Driver Installation
There are cases in which we want to allow certain users to install a device without administrative privileges. For
example, we can allow our users to install printers, cameras, USB drives, etc. We can do that by putting the
driver information into the driver store, but we can also allow them to install the drivers trough Group Policies.
In our case we will do that for our audio device. Let's go to the device properties, and then to the Details tab.
Here we will select the "Device class guid" property.
Figure 201 - Device Class GUID
The "Device class guid" identifies the drivers actual device. GUID is unique between all the different devices
installed on our computer. To get the GUID we have to have that device installed at least once on a computer.
There is no way to pull the GUID without installing the device. We will now copy that GUID by right-clicking
on it and selecting the Copy option. Now, we will open our local Group Policy editor. To open Group Policy
console, we can type "gpedit.msc" in the run menu. In Group Policy Editor we will go to Computer
Configuration > Administrative Templates > System > Driver Installation.
Figure 202 - Driver Installation Node
Here we have two settings. One is "Turn off Windows Update device driver search prompt". If we enable it,
this will remove the option that ask us if we want to check the Windows updates whenever our computer does
not have a driver. Another setting is the "Allow non-administrators to install drivers for these device setup
classes". Let's open that policy and enable it.
122
Management
Advanced Driver Management in Windows 7
Figure 203 - Enabled Policy
When we enable it, we can click on the Show button. Using the Show button we can add a GUID to the list of
classes which determines the devices which users can install without administrative privileges. We will rightclick on the Value field and select the Paste option. This GUID identifies the Audio device on our computer.
Figure 204 - List of Classes
From now on, all users will be able to install drivers for that device. This is great for devices which have to be
installed on many computers in our organization. For those devices we can make sure through local Group
Policy or Active Directory environment that users are able to install them.
Searching for Drivers
By default, when we try to install a new device, and we don't have the proper drivers already installed, and we
don’t have a driver in the driver store, we will be prompted for the installation media or to check Windows
update. In addition to this, we can also specify additional locations where drivers are searched for. To do that
we have to go to the Registry Editor. To do that, we will go to the run menu (search box), and enter "regedit".
123
Management
Advanced Driver Management in Windows 7
In Registry Editor we will go to the HKEY_LOCAL_MACHINE > SOFTWARE > Microsoft > Windows >
CurrentVersion. In the CurrentVersion we will double-click the DevicePath string.
Figure 205 - Device Path
By default, Windows only looks in the %SystemRoot%\inf location. We can add additional paths to be
searched by separating them by a semicolon. In our example we will also add a network location which
contains the drivers. The location is \\w2k8\drivers. The sub-folders in the path will also be searched.
Figure 206 - New Path
This way we can put all the different drivers for devices in our environment up on the "drivers" share.
124
Management
Staging a Driver in Windows 7
Staging a Driver in Windows 7
Before you start
Objectives: learn how to stage a driver in Windows 7.
Prerequisites: you have to know what drivers in Windows environment are.
Key terms: driver, windows, command, oem, pnputil, inf, install, published, store, case, device, realtek
Example Procedure
In this demonstration we will see how to pre-stage a driver in driver store in Windows 7. For the purpose of
this demo we have already downloaded a Realtek AC97 WDM Driver, and put it in
the C:\drivers\realtek\Win7. To stage a driver we will use a command line utility called pnputil. We have to
open our CMD with administrative privileges. To do that, right-click CMD and then select "Run as
administrator". Let's see all switches that we can use with pnputil command.
Figure 207 - Command Switches
If we run the "pnputil -e" command, we will see a list of all nonstandard drivers that are built in. These drivers
are pre-installed after the installation of Windows 7. Those drivers include drivers for printers, mice, etc.
Figure 208 - List of OEM Drivers
Notice that the published name for all drivers is OEM and a unique number. We can reference particular driver
using that unique published name. Let's now add a new driver to the driver store. We will use a "pnputil -a"
125
Management
Staging a Driver in Windows 7
command and give a path to the driver that we want to add. In our case the path
is c:\drivers\realtek\win7\alcxau.inf. The pnputil will first process the driver file.
Figure 209 - Adding Driver
Our driver doesn't have a valid digital signature that verifies who published it. Because of that we get a
Windows security warning. In our case we downloaded this driver from the publisher we trust, so we will go
ahead and install this driver anyway.
Figure 210 - Warning
Our driver was successfully imported. Notice that the published name for our imported driver is oem9.inf in
our case. Now that we have added our driver to the driver store, our users will be able to install the
corresponding device without the need to download the driver and without the need of entering administrative
credentials. So ordinary users will be able to install any device which has a pre-staged driver on our machine.
Figure 211 - OEM9.inf
For the purpose of this demo, let's now delete our driver. For that we will use the following command: pnputil
-d oem9.inf. The -d switch means that we want to delete it, and oem9.inf is the published name of our driver.
126
Management
Staging a Driver in Windows 7
Figure 212 - Driver Deleted
Our driver was removed successfully. As we can see, we can take advantage of the PnP utility to pre-stage a
driver into our Windows 7 installation. If a standard or nonstandard user tries to install device, they will not be
prompted for the actual driver, since Windows will install it automatically from the driver store.
127
Management
Using Disk Management and Diskpart to Mange Disks in Windows 7
Using Disk Management and Diskpart to Mange Disks in Windows 7
Before you start
Objectives: Learn how to manage disks in Windows 7 using Disk Management console and Diskpart
command line tool.
Prerequisites: you have to know the difference between the basic and dynamic disk, what is partition or
volume, and what file system is.
Key terms: disk, volume, space, create, partition, command, management, volume, mb, dynamic
Creating Simple Volume using Disk Management
To open Disk Management console, we can right-click Computer and select the Manage option. Then we will
go to the Disk Management section. We can also type "compmgmt.msc" in search to open the same
management console.
Figure 213 - Initialization
For the purpose of this demo we have added a new disk to the system which is 512 MB in size. This disk is
completely new, and the space on it is unallocated. Because of that, when we opened Disk Management we got
a prompt to initialize that disk. We have to do that before Logical Disk Manager can access it. In our case we
will select the MBR partition style and click OK. When we do that, notice that the status of the disk changed to
Basic and Online. Notice however that the disk is still unallocated.
128
Management
Using Disk Management and Diskpart to Mange Disks in Windows 7
Figure 214 - Disk 1
To create a new volume on the disk, we can right-click it and select the appropriate option. In this example we
will right-click on the unallocated space on our new Disk 1, select the "New Simple Volume" option and click
next. The first thing we have to do is to specify the volume size. In our case we will use 256 MB.
Figure 215 - Volume Size
On the next screen we have to choose the drive letter. We will use letter E.
Figure 216 - Drive Letter
On the next screen we will choose the NTFS file system and type in the volume name. We will perform a quick
format.
Figure 217 - Format Options
When we click Next and then Finish, we will see our new volume in the Disk Management Console.
129
Management
Using Disk Management and Diskpart to Mange Disks in Windows 7
Figure 218 - Simple Volume
Now, let's add additional disks to the system to perform more advanced disk management. We will add two
more disks, each having 512 MB of free space. Those two new disks have never been used before so we have
to initialize them before we can use them. To initialize disk, we can right click on the disk name and select the
Initialize Disk option.
Figure 219 - Initialize Disk 2
If we want, we can now extend or shrink our simple volumes. In our case we will right-click SimpleVolume,
select the "Extend Volume" option, and then click Next. We will get a list of all disks on our system. Notice
that the Disk 1 is already selected.
Figure 220 - Amount of Space
If we extend our volume by using free space from the same disk, our disk can remain a Basic disk. If we choose
some other physical disk, we will have to convert our disks to the Dynamic ones. We have to do the
conversion because when we use multiple disks, we are actually creating a Spanned volume. As you should
130
Management
Using Disk Management and Diskpart to Mange Disks in Windows 7
already know, Spanned volumes cannot be created on Basic disks. So, when we try to select multiple disks in
this case, we will get a warning about the conversion to Dynamic disks.
Figure 221 - Dynamic Disk Warning
If we choose to extend our volume, we will be able to do that without the conversion to Dynamic disk. In our
case we will extend our volume with the remaining space on our Disk 1, which is 253 MB in our case. Our
volume now has 509 MB in total.
Figure 222 - Disk 1 Extended
Creating Simple Volume using Diskpart
We can do the same thing with Diskpart command line tool. We will open elevated (with administrative
privileges) CMD. To do that, simply right-click it and select the "Run as administrator" option. Next, we will
enter diskpart tool and list all disks that are available on our system (all commands are highlighted).
Figure 223 - Diskpart
Notice that we have 4 disks available, and notice that all of them are initialized (status is online). The next thing
we will try to do is create a simple volume on Disk 2. First we have to select the disk and then enter the
appropriate command. To select the disk we will enter:select disk 2. To create a simple volume with the size
of 256 MB we will enter the command: create partition primary size=256.
131
Management
Using Disk Management and Diskpart to Mange Disks in Windows 7
Figure 224 - Create Partition
The next thing we have to do is format the partition and assign a drive letter to it. In order to do that we first
have to select the appropriate partition on the already selected disk. First we will list all partitions by using
the list partition command. Notice that we only have one partition on our disk so we will select it by using
the select partition 1 command. When we select the partition, we will format it by using the format fs=ntfs
label=SimpleDiskpartVolume quick command. So, the file system will be NTFS, the label will be
SimpleDiskpartVolume and we will do a quick format. After that we will assign a drive letter F by using
the assign letter=F command.
Figure 225 - Format Partition
And that's it. Our partition is now ready to use. To leave Diskpart we can enter the exit command.
Working with Dynamic Disks using Disk Management
For the purpose of this demo we will delete all simple volumes that we created up to now and convert our
disks to dynamic disks. To do that we can right-click on some disk and select the "Convert to Dynamic Disk"
option. After that, let's create a striped volume by using two available hard disks. We will right-click on
unallocated space on Disk 1 and select the "New Striped Volume" option. In our case we will use Disk 1 and
Disk 2, and the amount of space will be 256 MB.
132
Management
Using Disk Management and Diskpart to Mange Disks in Windows 7
Figure 226 - Amount of Space on Striped Volume
Drive letter will be E again, we will use NTFS file system and perform a quick format. Our disks now look like
this. Notice that we have one striped volume across two hard drives. This is actually software RAID
Figure 227 - Volumes
In the similar way we can create a spanned volume as well. We will right click unallocated space on Disk 1 and
select the "New Spanned Volume" option. We will use remaining space from Disk 1 and Disk 2. Our disks
now look like this.
133
Management
Using Disk Management and Diskpart to Mange Disks in Windows 7
Figure 228 - Volumes 2
Let's now create a mirrored volume. As you should know, we have to have two disks available in order to
create this type of volume. We have only one disk left so we will delete our spanned volume for now. Now, we
will select the mirrored volume from the remaining space on Disk 2 and the free space on Disk 3. Notice that
we have to have the same amount of space on both disks. We could not use the whole 512 MB from Disk 3
since we only have 255 MB available on Disk 2. Our disks now look like this (mirrored volume is red).
Figure 229 - Volumes 3
Mirrored volume is fault tolerant. The same information is written to both disks at the same time. That way if
one of the disks dies, we have another one with the same data. Also remember that we can only have two disks
in a mirrored volume. In contrast, striped volume can have more disks.
134
Management
Using Disk Management and Diskpart to Mange Disks in Windows 7
Now let's simulate a hard drive failure. Let's right click on Disk 2 and select the Offline option. Now let's see
the statuses of our disks. Notice that for mirrored volume the status is "Failed Redundancy". That means that
the data only exists on one disk and the other one doesn't contain the duplicates. However, we can still access
data on that volume. On the other hand, striped volume failed completely and we can't access data on that
volume any more.
Figure 230 - Disk Failure
As we can see, one failed disk can cause a lot of damage. Remember that it is always recommended to use the
hardware RAID device instead of software RAID, as we did here in this demo. If you use software RAID,
always make sure you have a proper backup set up.
135
Management
Disk Quotas in Windows 7
Disk Quotas in Windows 7
Before you start
Objectives: learn how to enable and configure Disk Quotas in Windows 7.
Prerequisites: you have to know what Disk Quotas are in general.
Key terms: quota, disk, users, space, case, level, limit, mb, warning, enable, entries, open, set, soft
Disk Quotas Tab
To work with Disk Quotas we have to open properties of our disk and then open the Quota tab. In our case
we will work on our E volume which is called "Striped" in our case. The first thing we need to do is click on
the "Show Quota Settings" button in order to view available settings.
Figure 231 - Quota Tab
Disk Quotas are disabled by default, so the first thing that we need to do is to enable them. We do that by
checking the "Enable quota management" option.
136
Management
Disk Quotas in Windows 7
Figure 232 - Quota Enabled
If we check the option "Deny disk space to users exceeding quota limit", we will actually enforce quotas. This
means that we will be using so called hard quotas. Hard quotas will actually restrict space usage, not only
monitor it. If we leave that box unchecked, we will actually use so called soft quotas. Soft quotas are only used
to monitor disk space, and users can go beyond their limits. When that happens, we will be able to see that in
Even Viewer. Remember that we set quotas on a volume level, for everyone. For the purpose of this demo we
will use a volume which has 500 MB of free space in total. Because of that space will limit disk space to 50 MB,
and set a warning level to 40 MB, for all users.
137
Management
Disk Quotas in Windows 7
Figure 233 - Limits
The warning level that we set here will only be visible in the Event Viewer, meaning that users will not know
that they reached the warning level. We can also choose to log all events in Event Viewer. In addition we can
see all quota entries by clicking the Quota Entries button.
Figure 234 - Quota Entries
Notice that Administrators don't have quota limits by default. Here we can also add exceptions for specific
users. However, we can't add exceptions to the group of users. To do that we can go to Quota from the menu
and select New Quota Entry. A new windows will open in which we have to find specific users. Notice that
only object that we can search are Users. In our case we will enter the "ivancic" name and click Check Names.
138
Management
Disk Quotas in Windows 7
Figure 235 - User Selection
When we click OK, we will get a new windows in which we will be able to choose if we want to limit disk
usage or not. In our case we won't limit the disk usage, since this is an exception to the quota limits that we
want to use for other users.
Figure 236 - ivancic Quota Limit
All other, new users will have new disk quotas applied, which is in our case 50 MB (40 MB warning level). Note
that in our case we have enabled soft quotas (tracking only).
139
Management
Disk Defragmenter Tool in Windows 7
Disk Defragmenter Tool in Windows 7
Before you start
Objectives: familiarize yourself on how to enable, configure and use Disk Defragmentation tool in Windows
7.
Prerequisites: you have to know what disk fragmentation is.
Key terms: disk, defragmentation, defragmenter, disks, tool, defrag, fragmented, button, click, run
Disk Defrag Tool
To open Defragmenter tool we can right-click our volume (E in our case), select Properties, go to Tools tab,
and then click on the "Defragment now" button.
Figure 237 - Tools Tab
On the Disk Defragmenter tool we will see all our disk and when the last defragmentation was run.
Figure 238 - Disk Defragmenter
As we can see, the scheduled defragmentation is enabled by default and it will run at 1:00 AM every
Wednesday. We can also modify that schedule. If we click the "Analyze disk" button, the system will check the
disk and tell us if we need to defrag our disk or not. Notice that our disks are barely fragmented (C: drive is
140
Management
Disk Defragmenter Tool in Windows 7
only 2% fragmented), which is great and we don't need to run defragmenter in our case. To defrag the disk we
can simply select it from the list and click on the "Defragment disk" button. Defragmentation can take a very
short time if the fragmentation is small or it can take up to several hours if the disk is big and badly
fragmented.
Remember that some files, like certain system can't be moved during the defragmentation process. Also,
network drives cannot be defragmented. By default, Windows 7 defragments our disks automatically. We can
also use defrag command in command line to defragment our disks.
141
Management
Removable Storage and System Security in Windows 7
Removable Storage and System Security in Windows 7
Before you start
Objectives: Familiarize yourself with security risks of removable devices and how to deal with them in
Windows 7.
Prerequisites: you have to know what Group Policy is.
Key terms: removable, devices, data, policies, media, security, set, deal, guid, restrictions
Security Issues
Removable devices actually represent a big security risk because they can be used to easily copy sensitive data to
it (to steal personal or confidential data). To deal with this problem we can use Removable Storage
Access policies in Group Policy. For example, we can forbid writing of data to removable media. We can also
prevent users from running software from removable media, or to copy data from the removable media to our
computer.
Group Policies related to hardware depend on the type of device. For example, we can set restrictions on our
CDs, DVDs, floppy drive, and removable disks. We can also set custom class restrictions which are based on
Globally Unique Identifier (GUID). A GUID is a 16-byte alphanumeric string specific to a device. We can also
restrict all removable storage at once.
We can deny read, write and execute actions on our removable devices. This also includes our mobile phones,
media players and similar devices (for this we use Windows Portable Devices (WPD) policies).
To enforce configured policies we can set the time to force reboot. If we don't configure this setting, policies
will not be take effect until the system is restarted.
To open Group Policy we can enter gpedit.msc in Search box. Removable Storage Access policies can be set
on the whole system or per-user basis. In our example we will forbid users to read and write to removable
disks. To do that we will go to Computer Configuration > Administrative Templates > System >
Removable Storage Access.
142
Management
Removable Storage and System Security in Windows 7
Figure 239 - Removable Storage Policies
In this window we will enable the following policies: "Removable Disks: Deny read access" and "Removable
Disks: Deny write access". Those policies will be active when the system reboots. We can also force the reboot
by using the "Time (in seconds) to force reboot" policy. Settings for users are available in User Configuration
> Administrative Templates > System > Removable Storage Access.
143
Management
Application Compatibility Issues in Windows 7
Application Compatibility Issues in Windows 7
Before you start
Objectives: learn how to use compatibility troubleshooter in Windows 7.
Prerequisites: you have to be familiar with different features in Windows which can be used to manage
application compatibility issues.
Key terms: compatibility, windows, case, program, settings, option, issues, problems, troubleshoot
Compatibility Troubleshooting
In our example we have a program called COMREG which has some problems running in Windows 7. The
first thing we will try is to troubleshoot compatibility. To do that we will right-click it and select the
"Troubleshoot compatibility" option. The troubleshooter will scan the application and see if it the problem can be fixed.
Figure 240 - Troubleshooting Options
In our case we have two options. The first option is to try recommended settings. Let's choose that option
now.
Figure 241 - Windows XP SP2 Compatibility
Notice that in our case the troubleshooter will apply create environment that corresponds to Windows XP SP2
system. If we choose the second available option (Troubleshoot program), we will be able to troubleshoot the
problem ourselves. In this window we can respond to several questions and that will help us to solve
compatibility issues. In our case we will select the first three options.
144
Management
Application Compatibility Issues in Windows 7
Figure 242 - Noticed Problems
When we click next we will be able to choose the version on which the program worked on. In our case we will
select the Windows 98 option and click Next.
Figure 243 - Windows Versions
On the next screen it will ask us about display problems that we noticed. In our case we will select the
transparency issues.
Figure 244 - Display Problems
Once we click Next we will be able to run our program with different settings applied.
145
Management
Application Compatibility Issues in Windows 7
Figure 245 - Applied Settings
If we go to the properties of that program, and then go to the Compatibility tab, we will see all the options that
were set during troubleshooting.
Figure 246 - Compatibility Tab
So, we can set all those options manually in Compatibility tab of the particular program. By default
compatibility settings will be saved for single user. If we want to force those settings for all users on the
computer we can click the "Change settings for all users" button. Note that some applications won't work even
146
Management
Application Compatibility Issues in Windows 7
if we set compatibility modes. If that is the case we can take advantage of the Windows XP Mode in Windows
7, which is actually a virtual Windows XP machine.
147
Management
UAC Configuration in Windows 7
UAC Configuration in Windows 7
Before you start
Objectives: Learn how to configure different aspects of User Account Control (UAC) in Windows 7.
Prerequisites: you have to know what is UAC in Windows.
Key terms: uac, settings, control, account, user, windows, desktop, policies, prompt, secure
User Accounts in Control Panel
To configure UAC settings we can go to Control Panel > User Accounts. Here we will see a "Change User
Account Control settings" option that we can use to make changes to the current user account.
Figure 247 - User Account in Control Panel
When we click that option, we will be able to choose when to be notified about changes to our computer. The
default setting is to notify us only when programs try to make changes to our computer. In this case UAC will
not notify us when we make changes to Windows settings. When the UAC prompt us activated, the Secure
Desktop (dimmed desktop) will be displayed for a maximum of 150 seconds. We will not be able to perform
any other action until we respond to the prompt. If we don't respond, the system will automatically deny the
request after 150 seconds.
148
Management
UAC Configuration in Windows 7
Figure 248 - UAC Settings
We can also choose the "Always notify" option in which we will be notified when programs try to make
changes and when we make changes to Windows settings. We can also choose to be notified but without
dimming our desktop (without Secured Desktop feature). In this mode we will be able to interact with the
computer even when the UAC prompt is active. We can also choose to never notify us. In this case we will be
able to do all administrative tasks (if we are a member of the Administrators group) without UAC prompts.
Standard users won't be able to perform actions which require administrative privileges in this mode, as they
will be automatically denied.
Group Policy Settings Related to UAC
We can also configure certain UAC settings by using Group Policy. This way we can control UAC settings
which will apply to the whole system, to all users. To do that we will enter "gpedit.msc" in Search. This will
open Group Policy Editor. In editor we will go to Computer Configuration > Windows Settings >
Security Settings > Local Policies > Security Options. Here we will scroll down to the policies which name
starts with "User Account Control: “
Figure 249 - UAC Policies
149
Management
UAC Configuration in Windows 7
Notice the different UAC Policies. We can configure the behaviour of the elevation prompt for administrators
and for standard users. Different settings which we can choose are shown on the pictures below.
Figure 250 - Prompt Settings for Administrators
Figure 251 - Prompt Settings for Standard Users
We can also control UAC settings for the built in administrator account. By default UAC is disabled for the
built-in administrator account, but we can enable it here. To turn UAC off or on we can use the "Run all
administrators in Admin Approval Mode". All other UAC policies are dependent on this option being enabled.
The default setting is on. In "Switch to the secure desktop when prompting for elevation" policy we can enable
or disable the Secure Desktop feature for the whole system. By using other policies we can also choose to only
elevate executable that are signed and validated or that are installed in secure locations. Signed and validated
applications use Public Key Interface (PKI) checks. Secure locations in Windows 7 are "C:\Program Files\"
and its sub-directories, "C:\Program Files (x86)\" and its sub-directories, and "C:\Windows\system32\r-".
150
Management
Configuring Security Zones in Windows 7
Configuring Security Zones in Windows 7
Before you start
Objectives: Learn where you can configure settings which will be used by Internet Explorer.
Prerequisites: you should be aware of different Internet Options available.
Key terms: security, internet, zone, sites, default, different, settings, configure, level, intranet
Zone Configuration
To configure Internet Options we will go to the Control Panel > Network and Internet > Internet Options.
The security settings applied to website depend on the corresponding security zone the website is in. We can
configure zones and security levels on the Security tab.
Figure 252 - Security Tab
The three default security levels are medium, medium-high and high. We can also use the "Custom level"
button to change the default security level of each zone and their details. This includes ActiveX control
behavior, scripting or user authentication settings.
Different zones will apply different security settings to websites that are in that zones. Local intranet zone
contains sites that are found on our intranet, in our organization. IE can detect intranet sites automatically. We
151
Management
Configuring Security Zones in Windows 7
can also manually add websites to this zone. The default security level of the Local intranet sites zone is
medium-low. To check default settings we can click on the Sites button.
Figure 253 - Local Intranet
Restricted sites are potentially malicious and that can damage our computer. The default security level for
restricted sites is high.
The Internet zone contains all websites that are not contained in the other three security zones. The default
security level for the Internet zone is medium-high. Internet Explorer also has a new feature called Protected
Mode. Protected mode will not allow infected IE to damage other parts of the Windows system. By default
Protected Mode is enabled for sites in the Internet and Restricted sites zone.
152
Management
Configuring Security Zones in Windows 7
Working with Libraries in Windows 7
Before you start
Objectives: Learn how to create new library, how to add new folders to library, and how to share a library.
Prerequisites: no prerequisites.
Key terms: library, sharing, adding location, documents library, music, video
Existing Libraries
Before we create our custom library, we should be aware that we already have some libraries configured on our
system. Libraries created by default are Documents, Pictures and Music. For example, if we right-click our
Documents and select Properties, we will get window like this:
Figure 254 - Library Properties
153
Management
Configuring Security Zones in Windows 7
Notice that in this case the Documents library currently includes locations "C:\Users\Admin\My Documents"
and "C:\Users\Public\Public Documents". Although we have two locations in Documents library, when we
open it, we won't see those locations. We will only see files and folders.
Figure 255 - Files in Documents
As you can see in this example, we only see files and folders from all locations which are included in the library,
but we don't know on which location they are located (until we go to its properties).
Creating New Library
There are several ways in which we can create custom library. For example, we can right-click "Libraries" in
Windows Explorer, select New, and then select "Library" option.
154
Management
Configuring Security Zones in Windows 7
Figure 256 - Creating New Library
When we do that, we will be able to change the name of the Library. In our case we will simply leave it New
Library.
Figure 257 - New Library
When the name is set, we can select our new library. Since we didn't include and folders in this library, we will
be prompted to include a folder.
Figure 258 - Include a Folder
The second way to create a library is to right-click some existing folder which we want to have in our library,
and then select the "Include in library" option, and then "Create new library" option. For the purpose of this
155
Management
Configuring Security Zones in Windows 7
demo, we have create two folders on our Desktop. One folder is "New Catalogs", and other is called "Old
Catalogs". We want to put those folders in one Library called Catalogs. To do that, we will first right-click New
Catalogs and create new library for it.
Figure 259 - New Catalog Folder
By default, the name of the library created in this way will be the same as the first folder that we added.
However, we can always right-click our library and choose to rename it.
Figure 260 - New Library
156
Management
Configuring Security Zones in Windows 7
To add another folder (Old Catalogs), we can right-click it, select the "Include in library" option, and then
select our newly created library from the list. Since we now have two locations in our library, we will rename it
to Catalogs. Our library now looks like this:
Figure 261 - Catalogs Library
If we right-click our library, and go to its properties, we see that we can choose to optimize our library for
certain type of items (like music, videos, documents, pictures or general items). This selection impacts how our
files will be presented in the library, and how they will be indexed.
Figure 262 - Library Optimization
If we take a look at our Catalogs library, we'll see that the default view (Arranged by option) is the folder view.
In this view we can see which files are located in which folder in our library. Also, when we create new files, we
can choose in which location we want to store them.
If we change the view to some other option than the "Folders" option, we will typically get a list of files from
all locations included in the library. For example, in our case we have created two text files in each location
157
Management
Configuring Security Zones in Windows 7
(New Catalogs and Old Catalogs folders), and we have selected the "Date modified" view in our Catalogs
library.
Figure 263 - Date Modified View
As we can now see, we don't know which file is located in which location. When we create a new file in this
view, that file will be saved directly to the first added folder in the library, which is New Catalogs in our case.
But, we can also change default save locations. To do that, go to the properties of the library, select the location
you want to be the default save location, and then click the "Set save location" button.
Including Network Locations
Another useful thing is that we can include shared folders in our libraries. To add a shared folder, we can
simply enter the UNC path to the folder when in the "Include folder" window. In our example we will include
the shared folder located on "ivancic-s" computer.
158
Management
Configuring Security Zones in Windows 7
Figure 264 - Including Shared Folder
The whole UNC path is \\ivancic-s\shared.
Sharing Libraries on the Network
The great thing about libraries is that they can be shared on the network. To share a library, simply right-click it
and select "Share with" option.
Figure 265 - Sharing a Library
Here we can select to share it on the HomeGroup or to share it with specific people.
159
Management
Printer Configuration in Windows 7
Printer Configuration in Windows 7
Before you start
Objectives: Learn how to install printer and how to manage it using Devices and Printers window in Windows
7.
Prerequisites: you have to know printer management concepts in general.
Key terms: printer installation, printer management, Windows 7, properties
Installing Printer
In today’s world, almost all printers are plug-and-play. In majority of cases we will simply plug in our printer,
and Windows will install drivers for it automatically. If it doesn't have drivers in its driver’s store, it will try to
find them in Windows update. If this fails, we can always install drivers which came with the printer or simply
download drivers from the manufacturer’s site and install them.
Despite that, we should be aware of how to add printer in Windows if we don't have self-installing drivers. For
example, we have connected Samsung ML-1640 printer to our computer. Windows tried to install it
automatically but the installation failed because Windows couldn't find the drivers.
Figure 266 - Error Message
Next, we downloaded drivers from the official website and installed them. In our case this solved the problem,
since we downloaded the EXE file which took care of installing drivers for us automatically. But, in some cases
with other printers we will only get ZIP file with driver files in it. In this case we have to add our printer
manually. To manage printers in Windows 7 we can go to Start > Devices and Printers. Here we will see a
button for adding a printer.
160
Management
Printer Configuration in Windows 7
Figure 267 - Device Manager
When we click on "Add a printer", we will be asked what type of printer do we want to install. We can choose a
local printer or a network printer.
Figure 268 - Type of Printer
If we select a local printer, we will be asked to choose a port. We can select an existing port or we can create a
new port. For the purpose of this demo we will use a USB001 port.
161
Management
Printer Configuration in Windows 7
Figure 269 - Port Selection
The next thing is to define the manufacturer and the model of our printer for the driver installation. Windows
already has many drivers available, which we can choose from the list. But, if our printer is not listed, we can
try selecting Windows Update option. If Windows Update doesn't work, we have to use the Have Disk option
which will enable us to select driver file manually. So, let's say that we have extracted our ZIP file which
contains drivers to C:\Temp, when we click Have Disk, we would click Browse, and navigate to the driver files
located in C:\Temp location.
Figure 270 - Install from Disk
You'll notice that Windows will only let you select Setup Information file (*.inf file). When you select the setup
file, you will be able to proceed and install the printer.
Managing Printer
Once the printer is installed, we can go to its properties. Notice that you can select two properties, one for the
device (Properties), and one for the printer itself (Printer properties). To see the properties of the printer itself,
we have to select the Printer properties. On the General tab we can see the name of the printer, available paper.
We can also print a test page here and change preferences.
On the Sharing tab we can choose to share our printer. Here we can also choose to add additional drivers for
different versions of Windows.
162
Management
Printer Configuration in Windows 7
Figure 271 - Sharing Tab
Notice that we have an option to render print jobs on client computer, which is selected by default. This way,
clients will do all the processing and just send the print job to the print spooler.
On the Ports tab we can see on which port our printer is located. Here we can select multiple ports, and
document will print to the first free checked port. Here we can add, delete and configure existing ports.
On the Advanced tab we can define the availability of the printer, select the driver for the printer, choose how
to spool documents, and other options.
On the Security tab we can modify permissions for our users. As you can see, by default everyone can print.
163
Management
Printer Configuration in Windows 7
Figure 272 - Permissions
The CREATOR OWNER can manage its documents. This is the user who created the print job, so it can
manage its own print jobs. Administrators will have all permissions. Of course, here we can add additional
groups and users and configure permissions for them.
Print Server
Every computer which has printer installed can act as a print server. Let's check this out by clicking "Print
server properties" button in Devices and Printers window. Here we will see tabs named Forms, Ports, Drivers,
Security and Advanced. On Forms tab we can define new forms with new measurements. On Ports tab we can
work with ports. On Drivers tab we can manage printer drivers on the computer. On the Security tab we can
define default permissions which will be defined for everybody and every printer.
164
Management
Configuring Power Options in Windows 7
Configuring Power Options in Windows 7
Before you start
Objectives: Learn where to find and how to work with Power Plans using GUI and CMD in Windows 7.
Prerequisites: you have to know what power plans are and why do we use them.
Key terms: power, plan, options, Windows 7, configuration, command line, powercfg
Power Options
We can find Power Options screen in Control Panel. The screen looks like this.
Figure 273 - Power Options Screen in Control Panel
Here we can see three built in power plans, Balanced, Power saver and High performance. We can choose the
one we want to use and we can customize the plan by clicking on the "Change plan settings" link. For example,
if we try to customize the Balanced power plan, we will see this.
165
Management
Configuring Power Options in Windows 7
Figure 274 - Power Plan Settings
So, we can choose when to dim the display or when to turn it off. We can also choose when to put the
computer to sleep and adjust the brightness of the screen. If we click on the "Advanced settings" link, we will
see this.
Figure 275 - Power Plan Advanced Settings
166
Management
Configuring Power Options in Windows 7
In this window we can change advanced settings for all three power plans (we can choose the plan on the drop
down list). For some options we will have to click on the "Change settings that are currently unavailable" since
some of the options need elevated privileges.
Note that we can't delete default power plans, but we can create our own custom power plan. To do that we
can click on the "Create a power plan" link in Power Options.
Figure 276 - Create a power plan Link
On the next screen we will have to choose the default plan that is closest to what we want (it will serve as a
template). In our case we will select "High performance" and call it "Custom HP".
Figure 277 - Power Plan Template and Name
On the next few screens we will be able to choose display and sleep settings. In our case we will choose that
our display never turns off and our computer never goes to sleep, and click the Create button. The new plan
will then be listed on the Power Options screen.
167
Management
Configuring Power Options in Windows 7
Figure 278 - New Power Plan Listed
We can always change settings for our new power plan. For example, if we don't want our hard disks to turn
off, we will enter 0 as a value for minutes.
Figure 279 - Hard Disk Timer
168
Management
Configuring Power Options in Windows 7
Command Line Power Plan Options
We can also manage power options from the command line. We have to run CMD as administrator (right-click
CMD and select "Run as administrator"). From the elevated command line, we can use
the powercfg command. If we want to list all available plans we can use the-list switch.
Figure 280 - Listing Power Plans in CMD
To change to another power plan we can use the -setactive switch. We have to use the GUID of the power
plan we want to change to. So, in our case, if we wanted to switch back to the Balanced power plan, we would
have to enter the following command: "powercfg -setactive 381b4222-f694-41f0-9685-ff5bb260df2e".
We can also export our settings by using the -export switch. We will have to specify the location and name of
the file, and the GUID of the plan we want to export. The command looks like this: "powercfg -export
C:\CustomHP 381b4222-f694-41f0-9685-ff5bb260df2e". Now that we have our plan exported, we can import
it on multiple computers by using a script.
To delete a power plan we can use the -delete switch and specify the GUID of the plan we want to delete, for
example: "powercfg -delete ae6a8d04-daf8-497f-ac3d-68dff990adc6". The plan we are trying to delete mustn't
be active.
So, we have actually deleted the CustomHP power plan that we have created earlier. Let's now try to import the
plan back by using the -import switch. The command looks like this: "powercfg -import C:\CustomHP". If
the import is successful, we will see the new GUID of the imported power plan (it will be different from the
previous, despite of the same name of the plan).
Of course, we can also delete and import power plans from the GUI, and we will see the options to delete the
plan if we try to change settings on the custom power plan which is not active (we can only delete custom
power plans).
169
Management
Configuring Power Options in Windows 7
Figure 281 - Delete this plan Link
To see the report of the power management settings, including diagnostics, we can use the -energy switch. The
system will be observed for some time in order to acquire data for the report. After that we will get the report
in a HTML format which can be opened with the browser.
Figure 282 - Energy Efficiency Analysis Command
170
Management
Configuring Power Options in Windows 7
Figure 283 - Example Energy Efficiency Report
To check the devices that can wake up the computer from sleep mode (like mouse or keyboard), we can use
the "-devicequery wake_from_any" switch.
171
Management
Configuring Offline Files in Windows 7
Configuring Offline Files in Windows 7
Before you start
Objectives: Learn how to enable and manage Offline Files in Windows 7, and how to resolve sync conflicts.
Prerequisites: you have to know what is Offline Files feature in Windows.
Key terms: Offline Files, Windows 7, configuration, Sync Center, conflicts, sync
Offline Files Configuration
The first thing we have to have is a shared folder with files in it. Then we have to open the Advanced Sharing
properties of that share and configure Caching options. So, this step is done on the server which is sharing the
folder.
Figure 284 - Caching Button
In Caching window, we can set which files are available to users who are offline.
172
Management
Configuring Offline Files in Windows 7
Figure 285 - Caching Options
The option "Only the files and programs that users specify are available offline" means that we have enabled
manual caching. The option "No files or programs from the shared folder are available offline" means that no
caching is allowed at all. The option "All files and programs that users open from the shared folder are
automatically available offline" means automatic caching. If we choose the "Optimize for performance"
option, executable files from the network share will be cached to the client machine. In our case we will leave it
to manual.
The next step is performed on the client machine. The first thing we should do on the client machine is check
the settings in Control Panel > Sync Center. Important thing to check here is the "Manage offline files" option.
In the window that appears we will be able to disable offline files feature and view our offline files.
173
Management
Configuring Offline Files in Windows 7
Figure 286 - General Tab
On the Disk Usage tab we will see how much disk space is currently used and available for storing offline files.
Figure 287 - Disk Usage
174
Management
Configuring Offline Files in Windows 7
On the Encryption tab we can encrypt offline files, and on the Network tab we can configure the time interval
to check for a slow connection. In our case we will leave all those options to default settings. The next thing to
do is to open the shared folder from our client machine. In our case, the UNC path to our shared folder is
//ivancic-s/scan. In that shared folder we have one file called "Demo text file". To make this file available
offline, we will right-click it and select the "Always available offline" option.
Figure 288 - Always Available Offline Option
Once the file is made available offline, we will see a state of the file as "Always available" at the bottom of the
Explorer window, when we select the file.
Figure 289 - File Status
If we lose network connectivity and try to open the shared folder again, we will see that the Status of the folder
is Offline, but the availability is Available.
Figure 290 - Offline Availability
This means that we can open up the shared file and work on it while we are not connected to the network, and
save all the changes. Once we connect to the network again, we the modified file will be synced with the file on
the shared folder on the server.
175
Management
Configuring Offline Files in Windows 7
Multiple Users
Keep in mind that if multiple users are working on the same files in the shared folder, we might encounter
conflicts when syncing cached files back to the server. If someone else from modifies the same file as we have
modified, we will see a conflict notification in our Sync Center.
Figure 291 - Conflicts
When we click on a specific conflict, we will be asked which version we want to keep.
Figure 292 - Resolve conflicts
We can choose to keep the file on our client machine, keep the file on the server, or to keep both files (one file
will be renamed). So, as we can see, offline files are primarily intended for personal use. If multiple users work
on the same files, there is a chance of overwriting changes on files made by other users, so keep that in mind.
176
Management
Managing Services in Windows 7
Managing Services in Windows 7
Before you start
Objectives: Learn where to find and how to manage services in Windows 7.
Prerequisites: no prerequisites.
Key terms: services, start, stop, manage, startup, Windows 7
Services Snap-in
To open the Services snap-in we can enter "services.msc" in the Search box. The snap-in with the list of
services will appear.
Figure 293 - Services Console
In the Services console we right-click a service and then choose what to do with it. We can start it (if it is not
running), stop it (if it is running), pause it, resume it and restart it.
177
Management
Managing Services in Windows 7
Figure 294 - Right-click Options
We can also go to the properties of the service. When we do that, a new window will appear. On the General
tab we can see the general information about the selected service and its startup type.
Figure 295 - General Tab
Note that we can change the startup type here. The startup type can be "Automatic (delayed start)", Automatic,
Manual or Disabled. Services that are set to startup automatically will start at boot time. If the startup type is
Automatic (delayed start), it starts just after the boot time which can result in faster boot. Keep in mind that
178
Management
Managing Services in Windows 7
some services require the startup type to be automatic in order to function properly. Manual startup type
enables Windows to start a service when it is needed, and we can always start this service from the Services
console by selecting the Start action. The Disabled startup type won't allow service to start even when it is
needed.
On the Log On tab we can see the account which is used to start the service.
Figure 296 - Log On Tab
We can even browse and select a specific user account that we want for the service to run in. The next tab is
the Recovery. Here we can select what the system will do if the service fails.
179
Management
Managing Services in Windows 7
Figure 297 - Recovery Tab
We can specify an option if the service fails once, two times and for the subsequent failures. We can select to
restart the service, select to take no action, to restart the service, to run a program or to restart the computer. If
we choose the Run a Program option, we will be able to specify the program that we want to execute and
specify the command line parameters if we need. Note that programs that we specify here should not require
user input. Otherwise the program will just stay open for the prompt for user intervention until the user
responds to the prompt. If we choose the Restart the Computer option, we will be able to specify after how
many minutes will the computer restart, and we can enter a message that will be shown to the user.
Note that on this window we also have an option to "Enable actions for stops with errors". All options set here
are for failures by default, but if we check the "Enable actions for stops with errors", all those options will also
apply for stops because of errors.
On the Dependencies we can see on which services our service depends on. We can also see services which
depend on our selected service.
180
Management
Managing Services in Windows 7
Figure 298 - Dependencies Tab
For example, if our service won't start, we can check if all the dependent services are started as working.
Services and CMD
We can also start and stop services from the command line (we have to run it as administrator). To start a
service we use the "net start" command. To stop a service we use a "net stop" command. If we only enter "net
start", we will get a list of running services on our machine. To start or stop a service, we have to know its
name. Services in Windows have two names - their easy-to-understand display names and their actual service
names, which is how their configuration is stored in the registry. To get the service name, the easiest way is to
run "sc query" command. This will list information about all the services on our machine, including the service
name and the display name. This list is long, so we should dump the results to a file by adding "> c:\file.txt"
to the command and then search the file for the service.
Figure 299 - Starting the Service Example
To do a restart of the service in the command line, we can combine the two mentioned commands using the
"&&" symbol. The command will look like this: "net stop {service_name} && net start {service name}".
181
Management
Managing Services in Windows 7
Another command we can use to start or stop a service is "sc start" and "sc stop". For example, to start a
service named Apache2.4, we would enter the command "sc start Apache2.4". To stop it, we would enter "sc
stop Apache2.4".
Figure 300 - Stopping the Service Example
We can also use "sc" to do many other actions with Services. To see other available actions, enter "sc" in CMD
and hit enter.
182
Management
Using msconfig in Windows 7
Using msconfig in Windows 7
Before you start
Objectives: Learn where to find msconfig and about different options that we can configure in it.
Prerequisites: you should know how to start or stop a service on the computer.
Key terms: msconfig, Windows 7, run, options, boot, startup,
msconfig Tool
To open msconfig tool in Windows 7, we can enter "msconfig.exe" in Search, and then select it. We can use
msconfig to configure startup type, boot options, service startup, and the startup of other applications.
Figure 301 - General Tab
General Tab
In the General tab we can select the startup type for our computer. As we can see, we can have the normal
startup, diagnostic startup and selective startup. In diagnostic startup the system will be booted but with basic
device drivers and basic services. In selective startup we can choose if we want to load system services and
startup items (which are visible in the Startup tab).
Boot Tab
On the Boot tab we can manage different operating system boot options.
183
Management
Using msconfig in Windows 7
Figure 302 - Boot Tab
Here we can choose the default operating system that will be booted. In our case we only have one OS
installed, but if we had more dual-boot or multi-boot, we would see other installations here. Also, we can select
to start our OS in Safe mode (Safe boot option). The Safe boot modes are:
Minimal - safe mode.
Alternate shell - safe mode with command prompt.
Active Directory repair - Active Directory restore mode.
Network - safe mode with networking.
Other boot options are:
No GUI boot - removes the graphical moving bar and / or Windows animation (Windows Welcome
screen) during start-up.
Boot log - set up a boot logger that will log everything that is loaded during the boot process, for
troubleshooting purposes. Log file is available after the boot in C:\Windows\ntbtlog.txt.
Base video - boot with base video drivers using lowest resolution and color depth. This is also known
as VGA mode in advanced boot options.
OS boot information - shows driver names as drivers are being loaded during the startup process.
We can also set the number of seconds in which the boot menu is displayed (the timeout option). We can also
make all those settings permanent for all future reboots, not just one single reboot.
On the Advanced settings we can specify the number of CPUs to be used, maximum memory, and debug port
and baud rate for remote debugging.
184
Management
Using msconfig in Windows 7
Figure 303 - Advanced Options
Services Tab
On the Services tab we can see a list of services and their status (running or stopped).
Figure 304 - Services Tab
Note that we can't start or stop a service here, but we can enable or disable it. When we disable a service, it
won't start the next time we boot. When we enable it, it will start when the machine reboots. This won't stop or
185
Management
Using msconfig in Windows 7
start the service immediately. The great thing here is that we can hide all Microsoft services by checking the
"Hide all Microsoft services" option. This gives us a great view of the third party services and their status.
Startup Tab
On the Startup tab we can see all the items that start during the user or computer boot.
Figure 305 - Startup Tab
We can see the item name, manufacturer, path to the executable, and the location of the registry key or
shortcut that causes the application to run. We can clear the check box for a startup item to disable it on the
next startup. Startup is a great place for viruses and other malware to plant them self, so this is a good place to
check if we have some suspicious startup items. Keep in mind that some startup items are important for our
system, and disabling those items can lead to undesired results. We should always check the name of the
executable on the Internet and find out why it is used, if its malware or not, and if we can safely disable it.
Tools Tab
Under the Tools tab, we can find and launch virtually all of the support and troubleshooting tools that we
might need to manage our system.
186
Management
Using msconfig in Windows 7
Figure 306 - Tools Tab
When we select a specific tool, we will also see the command that is used to start the selected item.
187
Management
Event Viewer in Windows 7
Event Viewer in Windows 7
Before you start
Objectives: Learn how to effectively use Event Viewer in Windows 7.
Prerequisites: you have to know what Event Viewer is.
Key terms: Event Viewer, Windows 7, Custom View, filter, configuration
Event Viewer
We can open Event Viewer in different ways, such as trough Computer Management and Administrative
Tools. However, the easiest way is to type "eventvwr" in search box, or "eventvwr.msc" in the Run box to
open the Event Viewer.
Figure 307 - Event Viewer
The standard Windows logs are now located under Windows Logs section (Application, Security, Setup,
System and Forwarded Events logs). If we select particular log, and then select some event, we will see the
summary of the event at the bottom of the Viewer, in the preview pane. On the right side we have options to
filter logs, to create custom logs, view properties of the event, etc. We can also see event properties by rightclicking the event, and then selecting the "Event Properties" option.
188
Management
Event Viewer in Windows 7
Figure 308 - Event Properties
Event properties give us more information about the event. If we go to the Details tab we can even get an
XML view if we need to save, parse it, etc. When we right-click an event, we also have an option to attach a
task to event. This way, if the event occurs again, the task will run. When we select the "Attach Task To This
Event" option, the Basic Task wizard will appear. The first thing we can do is give the name to the task.
Figure 309 - Task Name
On the next screen we can see that it will by default fill the log, source, and event ID information for us.
Figure 310 - Event Logged
189
Management
Event Viewer in Windows 7
On the next screen we can specify the action we want the task to perform.
Figure 311 - Task Action
If we select a program, we will be able to select a program or script that the task will run.
Figure 312 - Task Program or Script
If we specify to send an e-mail, we can specify from whom the e-email should come from, who will receive it,
subject, text, attachment, and we need to specify the SMTP server.
Figure 313 - Task E-mail
190
Management
Event Viewer in Windows 7
If we select a "Display a message" option, we will be able to specify a message that will appear on the desktop
when the event occurs.
Figure 314 - Task Message
So, this wizard will create a task in the Task Scheduler, based on the trigger from our event. Task Scheduler is
available in Administrative Tools. Tasks created by Event Viewer will be stored under "Task Scheduler Library"
-> "Event Viewer Tasks".
Figure 315 - Task Scheduler
Here we can see the details about our task, and even force it to run.
The next thing we should consider is the size of our logs. For example, if we right-click on the Application log,
and select the Properties option, we will be able to select the maximum log size.
191
Management
Event Viewer in Windows 7
Figure 316 - Log Options
The larger the size, the more events it can save, but at the same time, it takes up space and impacts
performance. We can also specify what to do when the maximum event log size is reached. The default is to
overwrite events as needed. If we specify the "Do not overwrite events" option, we will have to manually clear
the log. Also, users won't be able to use the computer until the log is cleared. Only the administrator will be
able to log on to the computer and clear the log.
In this window we also see the actual path to the log file and the current log size.
Figure 317 - Log Properties
Using Filters
We can filter our logs by choosing the Filter Current Log option from the Actions menu. In the filter we can
specify the event level (critical, warning, verbose, error, information).
Figure 318 - Filter part 1
192
Management
Event Viewer in Windows 7
Also, we can enter IDs, task categories, keywords, users, and computer to filter using this criteria.
Figure 319 - Filter part 2
Keep in mind that filters are only active only while we stay in the current log. If we select another log, the filter
will reset. If we want to define our own view with filters and preserve it, we can create a custom view from the
Actions menu. The custom view has the same options as when creating a filter. In our case we will create a
view which will only show us errors that happened in the last 24 hours in the Applications log.
Figure 320 - Custom View Example
Note that when we choose the log, we can combine multiple logs if we wish. We can even use the Applications
and Services Logs which can show us events from hardware, Internet Explorer, and even more details events
under the Microsoft section from other Windows services. Almost every major Windows service has its own
log.
193
Management
Event Viewer in Windows 7
Figure 321 - Different Logs
When we define our own view, we can name it and give it description. We can even organize our custom views
in folders.
Figure 322 - View Name and Folder
So, now when we select our custom view, only filtered events will be shown.
194
Management
Event Viewer in Windows 7
Figure 323 - Custom View in Action
We can always edit our custom view by right-clicking it and choosing the appropriate option, as well as export
it.
195
Management
Monitoring Performance in Windows 7
Monitoring Performance in Windows 7
Before you start
Objectives: Learn how to use Performance Monitor, Data Collector Sets, and Reports in Windows 7
Prerequisites: you have to know about Performance Management in Windows in general.
Key terms: performance, data collector set, report, Windows 7, demonstration.
Performance Monitor
In this demo we will take a look at how we can use the Performance Monitor to capture information about our
machine performance. We can access Performance Monitor by typing "perfmon" in the Start Menu search
box.
Figure 324 - Performance Monitor
If go to Monitoring Tools > Performance Monitor, we will see the performance of our machine in real time.
196
Management
Monitoring Performance in Windows 7
Figure 325 - Performance Demo
Here we only see data for our processor, by default. This counter has been added for us (Processor Time
counter). We can also monitor other things. Let's say that we want to monitor memory usage as well. To do
that we will click on the green plus sign (add button), and select the counter from the list. We can select the
counter form the local or remote computer. In our case we will select the Memory > Committed Bytes In Use
counter, which is also represented as percentage.
197
Management
Monitoring Performance in Windows 7
Figure 326 - New Counter
When we click OK, we should see both counters in the graph. By default, both our counters are now red, but
we can change the color of the counter if we click on it on the list of counters.
198
Management
Monitoring Performance in Windows 7
Figure 327 - Counter Properties
So, we can add multiple different counters from multiple different objects, if we want. In addition to the
Performance Monitor, we can use Data Collector Sets.
Data Collector Sets
We can use the Data Collector Sets to gather information about different times on our machine. If we rightclick on the Data Collector Sets > User Defined, we can select New > Data Collector Set option.
Figure 328 - New Data Collector Set
In the window that appears we give our set a name, and choose if we want to create it from the template or
create it manually. In our case we will do it manually.
199
Management
Monitoring Performance in Windows 7
Figure 329 - Name
On the next screen we can choose if we want to create data logs or alert. In our case we will select alert.
Figure 330 - Type
With this option we will specify that if something is above or below a certain value, a counter alert will be
thrown. So, on the next window we have to specify the counter which will be tracked. In our case we will
monitor the free space on our C: disk, presented as percentage. If the free space goes below 20 (%), the
counter alert will be thrown.
200
Management
Monitoring Performance in Windows 7
Figure 331 - Alert Settings
Here we can click on the Finish button, but if we click Next, we can set additional options. On the next
window we can choose to open the properties for this data collector set.
Figure 332 - Properties Option
In the Properties we can set many different options for our Data Collector Set. For example, on the Stop
Condition tab we can select when will our Data Collector Set stop running. We can choose to stop it based on
the overall duration or based on the limits of maximum size of the collected data.
201
Management
Monitoring Performance in Windows 7
Figure 333 - Stop Condition
We can also set a schedule for our Collector Set (on the Schedule tab). If we don't schedule the Collector Set,
we will have to start it manually. We can also change the directory where the Set will be stored (on the
Directory tab), choose who can work with it (on the Security tab), and specify the task that will run when the
set stops (on the Task tab).
Now, let’s go to the specific alert in our Demo Set and open its properties (right-click it and select the
Properties option).
Figure 334 - Right-click Alert
On the Properties of the alert, we will see the sample interval, which is 15 seconds by default.
202
Management
Monitoring Performance in Windows 7
Figure 335 - Alert Properties
On the Alert Action tab, we can specify an action. Here we can select to log the data in the application or start
another data collector set.
Figure 336 - Action Tab
On the Alert Task tab, we can select to run a task when this alert is triggered.
203
Management
Monitoring Performance in Windows 7
Figure 337 - Task Tab
To start the Data Collector Set, we have to select it and select the Start option.
Figure 338 - Start Data Collector Set
So the previous example was the Performance Counter Alert. We can also use Data Collector Set to create data
logs.
204
Management
Monitoring Performance in Windows 7
Figure 339 - Create Data Logs Option
In this type, we can also select the counter, but note that we can also collect current system configuration
information. Configuration information is pulled from the Windows Registry. We have to enter the registry
keys which we want to record.
Figure 340 - Registry Keys (Configuration)
To get the correct key, we can use Registry Editor and find the path to the key.
If we have two data collector sets, we can run one from the other. For example, since we now have an alert
data collector set (which runs when something goes below or above certain value), we can set its action to run
the other data collector set (which will gather data about our system).
205
Management
Monitoring Performance in Windows 7
Figure 341 - Running Another Data Collector Set
There are two default collector sets in Windows 7. One is the System Performance set, which collects
information about the CPU, hard disk drive, system kernel, and network performance. Another is the System
Diagnostics set which collects detailed system information in addition to the data gathered in the system
performance set.
Reports
We use the Reports tool to view the collected data or to create new reports from a set of data collector set
counters. Note that if a collector set has not run, no reports will be available. For example, we can run a System
Diagnostic report which includes the status of hardware resources, system response times, and processes on
the local computer. To generate this report we have to start the System Diagnostics data collector set in the
Performance Monitor. When it finishes, we can reach the report in the Report section.
Figure 342 - Report Example
206
Management
Using WinRS and PowerShell for Remote Management in Windows 7
Using WinRS and PowerShell for Remote Management in Windows 7
Before you start
Objectives: Learn how to enable Remote Management service, and how to use Windows Remote Shell
(WinRS) and PowerShell to send commands to remote computers.
Prerequisites: you have to know about remote management tools in general.
Key terms: Windows Remote Shell, WinRM, PowerShell, Remote Management, Windows 7
Windows Remote Management Service Set Up
To be able to manage and maintain computers remotely from the command prompt, the first thing we need to
do on each computer is to enable Remote Management. To do that we have to open the command prompt
with administrative rights and enter the "winrm qc" command.
Figure 343 - winrm qc Command
We have to say "Yes" to the prompt (just enter "y"). This command will set up Windows Remote Management
on the computer. Remember that we have to run this command on all computers which will participate in
remote management. For this demo, we have done this on our two Windows 7 desktop machines in our LAN.
Those computers are not members of Active Directory domain.
Trust Set Up
Once the Windows Remote Management service is set up, the next have to do is configure trusts between our
two computers. Have in mind that because these computers are not in the same Active Directory domain,
there's no Kerberos trust or certificate trust set between our computers. Because of that we have to manually
set up trust between our remote management services. Our first computer is named "WIN-7-VM1", and our
second computer is named "WIN-7-VM2". So, the "WIN-7-VM1" will trust "WIN-7-VM2", and vice verca.
On "WIN-7-VM1" machine we will enter the following command in elevated CMD:
207
Management
Using WinRS and PowerShell for Remote Management in Windows 7
winrm set winrm/config/client @{TrustedHosts="WIN-7-VM2"}
Figure 344 - Trust Win-7-VM2
On "WIN-7-VM2" machine we will enter the following command:
winrm set winrm/config/client @{TrustedHosts="WIN-7-VM1"}
Figure 345 - Trust Win-7-VM1
In Active Directory environment we wouldn't have to worry about this because all the clients have a Kerberos
trust.
Using Remote Shell
Now that the trust is set up, we can go and use the Windows Remote Shell command to run a command
remotely on another computer. Let's try and list directories from "WIN-7-VM1" computer in "WIN-7-VM2"
computer. To do that we will enter the command
winrs -r:WIN-7-VM2 ipconfig
208
Management
Using WinRS and PowerShell for Remote Management in Windows 7
Figure 346 - winrs Sending Commands
So, with this we have actually run "ipconfig" command on WIN-7-VM2 machine, and in that way found the IP
address of remote computer. To check the content of C:\ drive on remote computer, we would enter:
winrs -r:WIN-7-VM2 dir C:\
So, we can run any command we want on that remote machine.
But, we haven't specified the user which will be used to run our commands. The thing is, Windows Remote
Shell will try to negotiate authentication. If negotiation is not not successful, it will prompt us for the
credentials. If we want, we can also specify the user under which the command will run using the "-u"
parameter, like this:
Figure 347 - Command with Specified User
Note that we are prompted for user password.
PowerShell
We can also use PowerShell to manage remote computers. To open PowerShell, we simply enter "powershell"
in cmd.
209
Management
Using WinRS and PowerShell for Remote Management in Windows 7
Figure 348 - Enable PowerShell
In PowerShell we can also enter regular commands, but we can now also use advanced PowerShell features like
filtering or piping. Combining those features with remote management makes it even stronger. So, we can run
PowerShell commands on a remote machine using a "icm" command. We have to specify the name of the
computer, and then script or block of script. We can define a block of script by putting it in brackets. For
example, to get the ipconfig information from the "WIN-7-VM2", we would enter
icm WIN-7-VM2 {ipconfig}
Figure 349 - Remote Command Using PowerShell
Of course, we can use cmdlets:
Figure 350 - Sending cmdlets to Remote Computer
210
Management
Using WinRS and PowerShell for Remote Management in Windows 7
To shutdown remote computer:
icm WIN-7-VM2 {stop-computer -force}
To restart remote computer:
icm WIN-7-VM2 {restart-computer -force}
So, as we have seen we can send commands to remote machines. Practically, any command we can run locally,
we can also send to remote machine.
211
Management
Configuring and Using Remote Desktop in Windows 7
Configuring and Using Remote Desktop in Windows 7
Before you start
Objectives: Learn how to enable and how to use Remote Desktop Connection in Windows 7.
Prerequisites: you should know what Remote Desktop is in general.
Key terms: Remote Desktop, remote management, Windows 7, session
Remote Desktop
In this demo we will see how we can use Remote Desktop in Windows 7 to manage remote computers. The
first thing we need to do is enable Remote Desktop on the destination computer. We can do that in Control
Panel > System and Security > System > Remote Settings.
Figure 351 - Remote Settings
In Remote Settings we can allow Remote Desktop in two ways. We can allow connections from computers
running any version of Remote Desktop (less secure), or we can allow connections only from computers
running Remote Desktop with Network Layer Authentication (more secure). In our case we will select the
option with Network Layer Authentication since we only have Windows 7 machines on our network.
212
Management
Configuring and Using Remote Desktop in Windows 7
Figure 352 - Enable Remote Desktop
If we select the less secure version, we will be able to connect to this machine from Windows XP or even older
versions of Windows. Network Level Authentication will first authenticate the Remote Desktop connection
before opening the actual session.
By default only members of the Administrators and Remote Desktop Users local group are able to make
connections to a client running Windows 7 using Remote Desktop. On the Remote settings tab, we can click
on the Select Users button, and add additional users to this list. Those users will be added to the Remote
Desktop Users group. This list displays all the current members of that group.
213
Management
Configuring and Using Remote Desktop in Windows 7
Figure 353 - Remote Desktop Users
Initiating Connection
On the source computer we can go to Start > All Programs > Accessories > Remote Desktop Connection.
This will open the Remote Desktop Connection software.
Figure 354 - Remote Desktop Software
If we click on the "Options" link, we will be able to specify all options for the connection. On the General tab
we can specify the name of the remote computer.
214
Management
Configuring and Using Remote Desktop in Windows 7
Figure 355 - General Tab
In our case we will connect to "WIN-7-VM2" machine. We can also specify the username we want to use to
connect. We can also save this actual connection as a connection file. This way we will be able to simply
double-click on that connection file and the remote session will start with our saved settings.
On the Display tab we can show the Remote Desktop session in full-screen or use different resolution,
depending on our computer screen. We can also choose the color depth of the remote session. Lower color
depth can give us little better performance.
215
Management
Configuring and Using Remote Desktop in Windows 7
Figure 356 - Display Tab
On the Local Resources tab we can specify the audio, keyboard and devices and resources settings.
Figure 357 - Local Resources Tab
If we click on the Settings button in the "Remote audio" section, we can specify if we want to bring the audio
onto this computer, play it on remote computer or choose not to play audio. We can also choose to record
audio from our computer or not record audio at all.
216
Management
Configuring and Using Remote Desktop in Windows 7
Figure 358 - Audio Options
When it comes to keyboard settings, we can specify when to apply key combinations. In our case, when we are
in full-screen mode, the remote computer will receive the key combination we press.
Under "Local devices and resources" we can specify if we want to connect the printers that are on this source
computer into the remote computer so we can print from the remote computer to my locally attached printers.
We can even select to use local clipboard on remote computer. If we click More button under this section, we
can even specify if we want to use smartcards, serial or parallel ports, drives and other plug and play devices on
the remote machine.
Figure 359 - More Devices and Resources
On the Programs tab we can specify a program that we want to start when the connection establishes.
Figure 360 - Programs Tab
217
Management
Configuring and Using Remote Desktop in Windows 7
On the Experience tab we can select different visual settings for the session. The more options we remove, the
faster our connection will be, and vice versa. We can also simply choose a connection speed and it will optimize
all options automatically.
Figure 361 - Experience Tab
In our case we have selected LAN option, since we will be using this connection in our LAN.
On the Advanced tab we can configure server authentication settings when connecting to a server that does
not support Network Level Authentication. Here we can also configure settings to connect trough Remote
Desktop Gateway which allows us to connect to a remote computer on another network over a public or
Internet network.
Figure 362 - Advanced Tab
218
Management
Configuring and Using Remote Desktop in Windows 7
We have now saved this connection on our Desktop. When we double-click it, we will get this warning:
Figure 363 - Connection Publisher WarningSince we are not in a domain environment, there is no trust implemented between our two computers, so we
get a warning about that. In our case we know that it's a trusted computer, so we'll connect to it. We can also choose the "Don't ask again" option.
When we click Connect, we will be asked for credentials.
Figure 364 - Credentials
This is actually the Network Level Authentication part. There is no Remote Desktop session open until we
provide our username and password. If we didn't have Network Level Authentication enabled, it would first
open the Remote Desktop session and then would've asked us for credentials.
When connecting through Remote Desktop we are using certificates to secure the connection. Also, because
these machines are in a workgroup environment, the certificates are self-signed and created on each machine.
219
Management
Configuring and Using Remote Desktop in Windows 7
Figure 365 - Certificate
Since we trust this machine, we can click Yes, and the Remote Desktop session will be established.
When we connect to the client, we will see the actual desktop on the remote computer. Users on the remote
computer will see that someone is logged on remotely, but they won't see or be able to use the computer. So,
the shadowing is not supported and users on the remote computer can't view the screen. So, we actually take
control of the computer.
If we tried to login as a different user, and there was a user currently logged on the remote computer on the
other end, we would see this warning:
220
Management
Configuring and Using Remote Desktop in Windows 7
Figure 366 - Another User Warning
Also, the user on the remote machine would've been asked if they want to allow us to connect.
Figure 367 - Another User Question
If they don't respond, they will be logged out and we will be allowed to connect. Once we are connected, we
can simply click on the X mark to disconnect the session.
Figure 368 - Disconnect Button
221
Management
Configuring and Using Remote Desktop in Windows 7
We can also go to the Start menu and log off, and this will actually log us off from that remote machine. If we
disconnect, we actually stay logged on. So, this way we can connect to our remote machine again (or log on
locally with the same user account) and everything will be as we left it when we disconnected.
We can also run Remote Desktop from the command line. For example, to connect to the "WIN-7-VM2"
machine we would enter the following command:
mstsc /v:WIN-7-VM2
222
Management
Remote Assistance in Windows 7
Remote Assistance in Windows 7
Before you start
Objectives: Learn how to create invitations and use them to initiate Remote assistance connection.
Prerequisites: you have to know what Remote Assistance is in general.
Key terms: Remote Assistance, remote management, helper, Windows 7, invitation
Remote Assistance
The main benefit of Remote Assistance is that it can be initiated from remote user. Once the session is
established, we can view their screen and chat with the remote user.
In order for Remote Assistance to work, it must be enabled on the destination computer. By default, Remote
Assistance is enabled, but we can check this in the System Properties, on the Remote tag. To open System
Properties, go to Control Panel > All Control Panel Items > System.
Figure 369 - Remote Settings
Have in mind that Remote Assistance is different and separated from Remote Desktop. Computer can have
Remote Assistance access without having Remote Desktop enabled, and vice versa.
223
Management
Remote Assistance in Windows 7
If we click on the Advanced button, we can specify if we want to allow our computer be controlled or not, and
specify how long the invitations can remain open.
Figure 370 - Advanced Settings
When the Remote Assistance session is established, the person who is helping can request to control the
machine. We can take away that option by unchecking this box. By default, invitations last six hours after we
create them. If the invitation is not used until then, it will expire. On this window we can also make sure that
invitation cannot be run from any machine other than Windows Vista or later. If we check this, Windows XP
machines won't be able to use that invitation to initiate a Remote Assistance session.
Creating Invitations
To create an invitation, which is the first step in establishing a Remote Assistance connection, we can go to
Start > All Programs > Maintenance > Windows Remote Assistance. On this screen, we can either invite
someone to help us or we can help someone that's inviting us by opening their invitation.
224
Management
Remote Assistance in Windows 7
Figure 371 - Remote Assistance Window
Let's click on the "Invite someone you trust to help you". There are three ways in which we can create
invitation.
Figure 372 - Creating Invitation Options
We can save an invitation to a file and then send it to someone, send it using compatible e-mail program
(Outlook, Thunderbird, etc.), or use Easy Connect. Easy Connect works primarily with a LAN network. It
basically uses a form of broadcast mechanism where another computer on that same LAN can detect the Easy
Connect connection. As long as they have the password for the Remote Assistance, they can connect.
In our case, we will save the invitation as a file to our local C:\ drive. We can call it anything we want.
225
Management
Remote Assistance in Windows 7
Figure 373 - Saving Invitation
After that, we will see a invitation password.
Figure 374 - Invitation Password
This password needs to be communicated with the person who will help us. Otherwise without this password
they will not be able to connect.
Establishing a Connection
So, now we have sent this invitation that we have generated using web mail, and we have phoned the person
who will help us and told him the password. The user who will help us can establish a connection to us in two
ways. He can choose the "Help someone who has invited you" option from the Windows Remote Assistance
window. When he chooses that option, he will see this options.
226
Management
Remote Assistance in Windows 7
Figure 375 - Connection Options
So, he can click the "Use an invitation file" and then browse for the invitation he got from the remote user, or
he can try to use Easy Connect method. Another method is to simply double double-click the Remote
Assistance invitation file. This will open up Remote Assistance and ask us for the password.
Figure 376 - Password Prompt
When he enters the password, and clicks OK, he still won't be able to connect until we, on the other end, allow
him to connect.
Figure 377 - Allow Connection Prompt
227
Management
Remote Assistance in Windows 7
Once we click Yes, the connection will be allowed, and the user who is helping us will be able to view our
screen.
Figure 378 - Viewing the Screen
So, the default setting is view only, and helper can’t really interact with the machine. We can open the Chat
feature and chat with the remote user to give them directions.
228
Management
Remote Assistance in Windows 7
Figure 379 - Chat Button
The helper can also request control by clicking the "Request control" button.
Figure 380 - Request Control Button
We will receive a prompt asking us if we want to allow him to take control of our machine.
Figure 381 - Allow Remote Control Prompt
229
Management
Remote Assistance in Windows 7
Note that here we can also select to allow the helper to respond to User Account Control prompts as well. If
we don't select this, if any User Account Control prompts open up, the helper won't be able to respond to
them, but we at the actual computer will be able to respond to them. If we check this box, this will allow the
session to connect with the User Account Control prompts and allow the helper to respond to them.
To close the session we can click on the "Stop sharing" button, or simply close the Remote Assistance window.
Figure 382 - Stop Sharing Button
Have in mind, Remote Assistance requires both name resolution and TCP/IP connectivity.
230
Management
System Recovery in Windows 7
System Recovery in Windows 7
Before you start
Objectives: Learn how to restore to a previous point in time, and how to recover using system image in
Windows 7.
Prerequisites: you should know about different recovery options in Windows in general.
Key terms: restore point, system image, recovery, Windows 7, advanced boot
Restore Point
We can use restore points to recover from a damaged Windows installation. If we have problems with our
system, but we can still log on to Windows, we can open up the Backup and Restore console in the Control
Panel, and choose "Recover system settings or your computer" option, which is located at the bottom.
Figure 383 - Recover System Settings Option
Here we have the choice to open system restore.
Figure 384 - System Restore
When we open System Restore, we get this:
231
Management
System Recovery in Windows 7
Figure 385 - Restore Points
From here we can choose the restore point from the list. In our case we only have two restore points. In our
case we will choose the latest one and click Next. On the next screen we will get a description of our action.
232
Management
System Recovery in Windows 7
Figure 386 - Confirmation
Keep in mind that system restore does not touch our user files. Only system data and system settings will be
affected. When we click finish, the restoration will begin. Reboot will be required.
System Image Restore
If restoring to a restore point doesn't help, we can do a complete image recovery. If we go back to the Restore
window, we will see a "Advanced Recovery Methods" option.
Figure 387 - Advanced Recovery Methods Option
In advanced methods, we can use a system image which we created earlier, or we can reinstall from scratch
using Windows installation media.
233
Management
System Recovery in Windows 7
Figure 388 - System Image or Windows Reinstallation
When we try to use system image option, it will first ask us to back up existing files, before continuing. After
that it will ask us to reboot our computer, after which we will be able to select the system image to restore
from. The media on which the image is located has to be connected to the computer.
All this is great, but what if we can't boot to our system at all.
Boot and System Startup Problems
If we can't boot to our system at all, we can boot to Windows Recovery Environment using System Repair
Disk, or Windows installation media, or we can push F8 key during the boot to see Advanced Boot Options. If
we use Windows 7 installation media, the first thing we see is this screen, on which we can click Next.
234
Management
System Recovery in Windows 7
Figure 389 - Windows Installation
On the next screen, instead of clicking the "Install now" option, we click the "Repair your computer" option.
This will show us system recovery options.
235
Management
System Recovery in Windows 7
Figure 390 - Repair Your Computer Option
If we don't have Windows installation media or System Repair Disk, we can try and press the F8 key on our
keyboard during boot. We will get a menu like this:
236
Management
System Recovery in Windows 7
Figure 391 - Advanced Boot Menu
On this menu we select the "Repair Your Computer" option which will show us a list of recovery tools.
Figure 392 - Recovery Options
On this screen we will select System Image Recovery Option and then select the system image we created
earlier. From this point on, we will be asked about how we want to partition our disks (do we want to keep
237
Management
System Recovery in Windows 7
current partitions or use partitions from the image), and we will also be warned that we will lose all current data
on our disk (since the restore will use all data from the system image and overwrite all existing data).
238
Security
Credential Manager in Windows 7
Security
Credential Manager in Windows 7
Before you start
Objectives: Learn what is Credential Manager, why it is used, where to find it, and how to manage saved
credentials used to gain access remote resources.
Prerequisites: you have to be familiar with tools which can be used in Windows to manage authentication
locally, with sharing permissions, with UNC paths, and with Windows user accounts.
Key terms: credentials, Windows, ID, access, manager, password, username, vault, resource, provider
What is Credential Manager
Whenever we try to access some resource, whether it is local or remote resource, Windows always validates our
credentials to make sure we have rights to access that resource. To avoid entering our credentials every time,
we can use Credential Manager to save our credentials. That way Windows will automatically use credentials
from the Manager, instead of asking us to enter them. In our case we will try to access files on remote
computer over network. The name of the remote computer is "lenovo". We will use the UNC path to access
that computer. UNC path is:
Figure 393 - UNC Path Example
When we click OK, we will be asked to enter our credentials. We will do that now.
239
Security
Credential Manager in Windows 7
Figure 394 - Credentials Entered
Notice that we can check "Remember my credentials" box. If we don't check that box, we will have to enter
our credentials every time we want to access this resource. Remember that in this case our computers are not
on a Windows domain. If we were on a domain, Windows would automatically check our credentials against
Active Directory. Since we are working with local user accounts, we must specify the name of the computer
where the user is located. This is because every computer in the Workgroup environment has its own users.
That's why we have entered "lenovo\mediacenter" as the user name, "lenovo" being the name of the
computer, and "mediacenter" being the actual username. So, we have to know the username and password
information located on the computer that we want to connect to. This is how Workgroup environment works.
We will also check the "Remember my credentials" box.
Once we click OK, if we entered credentials correctly, we will be connected to the Lenovo computer. We can
see that there is one shared folder and one shred printer on that computer.
Figure 395 - Connected to Lenovo
240
Security
Credential Manager in Windows 7
If you are unable to connect to the remote machine, and you are sure that you have entered username and
password correctly, make sure that remote access and sharing is enabled on your remote machine. You can do
that in Network and Sharing Center under Advanced Sharing Settings.
Managing Credentials
Since we have chosen to save our credentials we will be able to access our remote resource without entering
our credentials again. But the question is, where are those credentials saved? The answer is the Security Vault
which we can manage using the Credential Manager located in Control Panel.
Figure 396 - Credential Manager
Notice that under Windows Credentials section we have saved user name and password for the "lenovo"
computer. Here we can edit that credential or remove it from the vault. We can even add additional Windows
credentials by specifying the name of the server, username and the password.
241
Security
Credential Manager in Windows 7
Figure 397 - Adding Credentials
We can also enter certificate credentials if we want to authenticate with the resource using certificates or smart
cards. We can even enter generic credentials for non-Windows resources like websites or applications.
Figure 398 - Different Credentials
We can always backup our vault. To do that we can simply click on the "Back up vault" option. In our case we
will save them to the Desktop, but for restoring, it is better to save them to removable media.
Figure 399 - Vault Backup Location
When we click Next, we have to somehow protect those credentials. Before we enter the password for our file
Windows 7 wants us to enter Secure Desktop and to do that we are prompted to press Control+Alt+Delete.
Once we are in Secure Desktop we can go ahead and enter a password for our backup file.
242
Security
Credential Manager in Windows 7
Figure 400 - Backup Password
Now that we have our credentials backed up, we can always restore them using the "Restore vault" option in
Credential Manager.
In Windows 7 we can also link our Windows account to an online ID. With online IDs we can easily access
online resources with our online ID. To link our Windows account to an online ID, we can simply click on the
"Link online IDs" option.
Figure 401 - Online ID
The first thing we have to do is install an online ID provider. When we click on the "Add an online ID
provider" option, we will be redirected to a web page where we can download ID providers. At the time of
writing this article there is only one option and that is Windows Live Sign-in Assistant.
243
Security
Credential Manager in Windows 7
Figure 402 - Web Page with Providers
So we will download that provider and install it. When the provider is installed, it will be available in the Online
ID Provider list.
Figure 403 - Installed Providers
When we link our account with our Windows Live ID, we won't have to enter credentials for resources related
with that online ID.
244
Security
Running Apps as Different Users with Run As in Windows 7
Running Apps as Different Users with Run As in Windows 7
Before you start
Objectives: Learn how to run different apps in Windows 7 by different users for testing purposes. We will be
using the Run As feature for this.
Prerequisites: no prerequisites.
Key terms: Run As, user account, Windows 7, application, app, right-click, command line
Run As
When we right click some application, we will see an option to simply open the application, or to run it as
administrator.
Figure 404 - Right-Click Menu
If we choose the "Run as administrator" option, the app will open with administrative rights. One other option
that we have is to hold the Shift key while we right click on the app icon. This will bring the "Run as different
user" option on the list.
Figure 405 - Shift + Right Click Menu
245
Security
Running Apps as Different Users with Run As in Windows 7
With the "Run as different user" we can open the app with someone we actually specify. This way we can test
applications as other users. In order for this feature to work, the service "Secondary Logon" has to be started.
Figure 406 - Secondary Logon Service Started
The Secondary Logon service is configured to start manually by default. So, we should set it to start
automatically if we plan to use "Run as different user" feature.
Let's see an example. We have a user account named Students which is member of the Users group only.
Figure 407 - Students User Account
Now, let's try to open Computer Management snap-in as that user and try to do some things that only
administrators should be able to do. First we will right click Computer Management and choose the "Run as
different user" option.
246
Security
Running Apps as Different Users with Run As in Windows 7
Figure 408 - Running Computer Management
Btw. Computer Management icon can be found in Control Panel > Administrative Tools (icons view). When
we do that, the Windows Security window will appear. Here we have to enter the user name and the password
of the user which we want use to open the application (Students in our case).
Figure 409 - Windows Security Window
The Computer Management console will appear. Keep in mind that we will be able to do some actions as
ordinary user here, but some actions should be denied. For example, if we try to create a new user account in
the Local Users and Groups, we will get a warning like this:
247
Security
Running Apps as Different Users with Run As in Windows 7
Figure 410 - User Creation Denied
We were denied to create a new user. Remember, this happened because we ran the Computer Management
console as a Students user account which is member of the Users group only (it doesn't have administrative
rights).
Also, let's try to check Device Manager and see what happens.
Figure 411 - View Only Device Manager
We got a warning that we can only view device settings (not change them), since we are logged on as a standard
user (actually we ran the app as a standard user). So, as we can see, this feature is great if we need to test how
our apps will behave when different types of users try to use them.
Run As in Command Line
We can use the Run As feature in the Command Line. The command is the "runas". We have to specify the
user which we want to use, and we also have to specify the app we want to run. We have to use the full path to
248
Security
Running Apps as Different Users with Run As in Windows 7
the application. In our case we will again use the Students user account and we will try to open the Registry
Editor. The full path to Registry Editor app is C:\Windows\system32\regedit.exe. The full command looks
like this: runas /user:Students C:\Windows\regedit.exe. When we hit Enter, we will be prompted to enter
the password for Students.
Figure 412 - runas Command
We can specify to save the credentials so we don't have to enter the password every time we run the
command. To save the credentials, we simply enter /savecred switch in the command, like this: runas
/user:Students /savecred C:\Windows\regedit.exe. We can use the Credential Manager (located in Control
Panel) to manage saved credentials.
Keep in mind that runas cannot execute an application that requires elevation if the target user account's UAC
settings include prompt for consent or prompt for credentials.
249
Security
User Account Policies in Windows 7
User Account Policies in Windows 7
Before you start
Objectives: Learn where to find policies related to user accounts, user passwords, account lockout, and user
rights.
Prerequisites: you have to know what a user account is, and what is Group Policy Editor.
Key terms: Policy Editor, user rights, account lockout, Windows 7, policies, settings, users
Local Group Policy Editor
We can manage user rights and accounts policies using local policy editor. To open Local Group Policy Editor
in Windows 7, we can enter "gpedit.msc" in search and click on the gpedit option in search results. In Policy
Editor we can then go to Computer Configuration > Windows Settings > Security Settings. Here, the first
thing we will check is User Rights Assignment under Local Policies.
Figure 413 - Policy Editor
User Rights Assignment
In this section we will first see a predefined policies that are set on our machine. For example, we can see who
(which groups of users) can access this computer from the network, who can log on locally, who can log on
trough Remote Desktop, who can back up files, etc. For example, in our case we see that users in groups
"Everyone", "Administrators", "Users", and "Backup Operators" can access our computer from the network.
Figure 414 - Network Access Policy
250
Security
User Account Policies in Windows 7
Of course, we can change those settings to suit our needs. For example, if we select "Allow log on trough
Remote Desktop Services" policy, we add specific user or group of users to the list, or remove them.
Figure 415 - Remote Desktop Users
Account Policies
Under Security Settings let's check Account Policies. Under Password Policy we can change things such as
maximum and minimum password age, minimum password length and complexity requirements, etc.
Figure 416 - Password Policy
In our case these settings are not configured, but we can change that to suit our needs. For example, it is a
good idea to change the minimum length of passwords from 0, to prevent blank passwords.
251
Security
User Account Policies in Windows 7
Figure 417 - Minimum Password Length
If we set the "Minimum password age" option to 5, users who change password won't be able to change it
again for 5 days. Minimum and Maximum password age options are only applied to users which don't have
"Password never expires" option set. For example, user Kim Verson has "Password never expires" option
checked, so minimum and maximum password age is not applied to Kim (we have used Local Users and
Groups in Computer Management to check this).
Figure 418 - Password Never Expires option
If we enable Password history policy, users will have to use unique passwords every time they change it.
Maximum password age has to be configured for password history to take effect. Maximum password age
enforces users to change passwords after specified length of time. Password complexity policy prevents using
simple passwords which are easy to crack. If we set that option, users will have to use special characters in their
passwords, with minimum of 6 characters, and won't be able to use dictionary words or any part of user login.
If we set the "Store passwords using reversible encryption" should not be set, since passwords will essentially
be readable as plaint text.
252
Security
User Account Policies in Windows 7
The next thing we can check is Account Lockout policy.
Figure 419 - Account Lockout
Keep in mind that these account lockout policy applies to all users on local computer, including the
Administrator account. If we only have one administrative account on the machine and that account gets
locked out, we won't have any way to log in to the machine with the user which has administrative rights any
more. This is the case on local machines, so we should be careful when setting account lockout policy on local
machines. The value of 0 in "Account lockout threshold" means that accounts won't be locked out. If we
specify some other number here, the system will count invalid log on attempts and then lockout the user after
the specified threshold. We can also specify the duration of the lockout and how much time the counter of
invalid log on attempts is remembered.
253
Security
Editing NTFS Permissions in Windows 7
Editing NTFS Permissions in Windows 7
Before you start
Objectives: Learn how to properly manage NTFS permissions and their inheritance, how to configure special
(advanced) permissions, and how to check effective permissions in Windows 7.
Prerequisites: you have to know what NTFS permissions are.
Key terms: NTFS, permissions, files and folders, Windows 7, special permissions, effective permissions,
permission configuration
Folders
For this demonstration we have created an "NTFS demo" folder on our C partition. Inside of that folder we
have three subfolders: "Admins", "Kim Verson", and "Marko".
Figure 420 - Subfolders in "NTFS demo" folder
In our case, we want to allow access to certain folders only for specific users. For example, only computer
administrators should have access to the "Admins" folder. Only administrators and Kim Verson should have
access to the "Kim Verson" folder, and only administrators and user Marko should have access to the "Marko"
folder.
Inheritance
As you should already know, child objects (files and folders) inherit permissions from their parent, by default.
So, in our case, by default, "NTFS demo" folder will inherit permissions from the C drive. Let's check this out.
We will right click the "NTFS demo" folder and go to its properties, then open the Security tab, and then click
on the Advanced button.
254
Security
Editing NTFS Permissions in Windows 7
Figure 421 - Inherited From Column
Notice that the option "Inherit inheritable permissions from this object's parent" is checked by default. Also,
notice that permissions are inherited from "C:\". The next thing we should do on the "NTFS demo" folder is
remove inheritance. This way, our new permissions won't be affected by the permissions set on the C drive. To
remove inheritance, we can click on the "Change Permissions..." button on the Advanced window, and then
uncheck the box for "Include inheritable permissions from this object's parent" option. When we do that, the
Windows Security window will appear.
255
Security
Editing NTFS Permissions in Windows 7
Figure 422 - Inheritance Warning
At this point we have to options. We can keep all current permissions on that folder and then work with them,
or we can remove all current permissions and set new ones from the beginning. The recommended thing to do
is to Add current permissions, which will make all current permissions explicit. This way we know which
permissions were previously set on the object. When we do that, notice the "Inherited From" column. It
changed from "C:\" to "<not inherited>", which is what we want for "NTFS demo" folder.
Inheritance Removed
Now we can manually make changes to permissions on "NTFS demo" folder, and permissions on C drive
won't affect them. But, what about subfolders in "NTFS demo" folder. Let's check the Security tab for "NTFS
demo" folder, and for one subfolder, for example, "Admins".
256
Security
Editing NTFS Permissions in Windows 7
Figure 423 - Explicit and Inherited Permissions
Notice that the Allow column for "NTFS folder" has black check marks, while "Admins" folder has check
marks which are grayed out. This means that permissions for the "Admins" folder are inherited. Let's click on
the Advanced button on the Security tab for the "Admins" folder.
Figure 424 - Admins Folder Inheritance
Notice that subfolders in "NTFS demo" folder now inherit permissions from the "NTFS folder" itself.
Proper Inheritance
Now we have one problem which considers inheritance. All subfolders in "NTFS demo" folder have the same
permissions as "NTFS demo" folder. This is a problem because if we check permissions on the "NTFS demo"
folder, we will see that all users have access to that folder, and since subfolders will inherit those permissions,
all users will have access to all subfolders in "NTFS demo" folder, which is not what we want. Because of that
fact, we have to modify permissions on the "NTFS demo" folder. First, we will remove all permissions except
for the Administrators group, which can have full control. Our permissions on the "NTFS demo" folder now
look like this.
257
Security
Editing NTFS Permissions in Windows 7
Figure 425 - Administrators Only
If we only leave it like this, only administrators will have access to "NTFS folder" and its subfolders. Since all
users have to go to "NTFS demo" first to get to their own folder, we also have to ensure that other users can
list "NTFS demo" folder content. Beware that we also have to ensure that they don't have access to all
subfolders in "NTFS folder", but only their specific subfolder. For this to happen, we will add permissions for
"Authenticated Users" group again and give it the "Read & Execute" permission. Authenticated Users group
contains all users which log on to the machine. We should always use Authenticated Users group instead of
Everyone group, since users have to at least authenticate to get access. Everyone group will enable access for
anonymous users as well.
258
Security
Editing NTFS Permissions in Windows 7
Figure 426 - Authenticated Users Group Added Back
If we leave it like this, this permission will again be propagated to all child objects in "NTFS demo" folder. We
have to change that. We have to set this permission only for "NTFS demo" folder. For this we have to click on
the Advanced button on the Security tab, and check the Apply To column. Notice that now permissions will be
applied to this folder, subfolders and files.
Figure 427 - Apply To Column
To change this we will click on the "Change Permissions..." button, and double click on the permission for
"Authenticated User". On the "Permission Entry for NTFS demo", we will change the "Apply to" option to
"This folder only".
259
Security
Editing NTFS Permissions in Windows 7
Figure 428 - Apply To Propagation Option
When we do that, permission for Authenticated Users group will only be applied for "NTFS demo" folder, and
not its subfolders. This way we ensure that all users can access "NTFS demo" folder, but don't have access to
specific subfolders.
So, the next thing to do is give explicit permissions to specific user for certain subfolder in "NTFS demo"
folder. For example, we will give the Modify permission to user Kim Verson for subfolder "Kim
Verson". Remember that maximum permission we should give to ordinary users is the Modify permission.
The difference between "Full control" and "Modify" permission is that users with "Modify" won't be able to
take ownership of the object or change its permissions.
260
Security
Editing NTFS Permissions in Windows 7
Figure 429 - Kim Verson Explicit Permissions
To conclude, we have enabled access for all users to "NTFS demo" folder by using Authenticated Users group
which is not propagated to subfolders. Administrators have full control on "NTFS demo" folder, and this
permission is propagated to all child objects (files and folders) in "NTFS demo" folder. We have set explicit
permissions for specific users so that they can access their own subfolder (additional, explicit permissions, can
be added even when inheritance is enabled).
Special Permissions
As you should know, the 6 standard NTFS permissions are actually collections of more granular, special NTFS
permissions. For most situations, standard permissions provide enough control. In some situations we might
need more specific NTFS permissions. In fact, we already used special permissions when we set the
propagation level of permission in previous example. Propagation level is configured using the "Apply to"
option in advanced permission configuration. We have several options here like "This folder only", "Subfolders
and files only", "Files only", etc.
We can also configure special permissions for users in a way that they can only create new objects, but can't
delete them (or vice versa ;) ). For example, let's add a special permission for user Marko for the subfolder
"Marko", so that he can only add new files and folders, but can't delete them. For that we will go to the
Security tab and add user Marko with "Read & Execute" permission. Next, we will click the Advanced button,
261
Security
Editing NTFS Permissions in Windows 7
and then click on the "Change Permissions..." button, and click on Edit button for Marko entry. Here, we will
see that some special permissions will already be selected because we gave Read & Execute permission
previously. So, for user to be able to add new objects, we also have to select permissions "Create files / write
data", "Create folders / append data", "Write attributes", and "Write extended attributes". Since we don't want
to allow user to delete files and folders, we won't select permissions "Delete subfolders and files", and
"Delete".
Figure 430 - Special Permissions Example
Effective Permissions
To check the effective permissions for specific user or group, we can go to Effective Permissions tab in
Advanced section. For example, let's check what permissions has the Users group on the "Marko" folder.
262
Security
Editing NTFS Permissions in Windows 7
Figure 431 - Effective Permissions Example
In our case, the Users group doesn't have any permissions on the "Marko" folder, and this is what we want.
Effective permissions can be very useful when we want to check permissions for users which belong to
multiple groups, because it also takes into account the inheritance and propagation levels. This way we don't
have to manually calculate the final permissions.
263
Security
Advanced Sharing Settings in Windows 7
Advanced Sharing Settings in Windows 7
Before you start
Objectives: Learn where to find and which options to configure when it comes to advanced sharing options in
Network and Sharing Center for Windows 7.
Prerequisites: no prerequisites.
Key terms: sharing options, network and sharing center, network discovery, public folders, file and printer
sharing, media streaming, password protected sharing
Network and Sharing Center
Window 7 has a special place where we can view our network information and set up connections. It's called
Network and Sharing Center and we can find it in Control Panel > Network and Internet > Network and
Sharing Center. This is a central location where we can perform all networking and sharing tasks.
The first thing we should be aware of is the location of our network connection. For each network connection
we choose a network location. The location identifies the type of network we are connecting to. This controls
firewall and security settings, and controls enabled services. The location types are:
Domain - in this case computers are connected to an Active Directory domain. This location type will
be selected automatically when we join our computer to the domain.
Public - this location means that we are on untrusted network.
Home - this location is a trusted (also called private) local area network
Work - this location is a trusted (private) local area network. This option is typically used when
domain is not implemented in work environment.
When we connect to a new network, we will get a prompt to choose the location for our network connection.
We can always change this later, if we need to.
264
Security
Advanced Sharing Settings in Windows 7
Figure 432 - Network Location Prompt
When it comes to sharing, we should first check settings on the "Change advanced sharing settings" option in
our Network and Sharing Center.
Figure 433 - Advanced Sharing Options
265
Security
Advanced Sharing Settings in Windows 7
Advanced Sharing Settings
Here we fill find advanced sharing options, which are configured for each network profile. A separate network
profile is created for each network we use. For different profiles we can have different sharing options
depending on the network we are connected to.
Figure 434 - Different Network Profiles
In our case we are currently connected to our work network, so let's check out options in that profile. The first
option is "Network discovery". Network discovery option enables our computer to discover (to see) other
computers on the network, and other computers will be able to discover our computer.
Figure 435 - Work Profile Part 1
Keep in mind that if we disable Network discovery, we don't disable other forms of sharing. As you can see on
the picture, File and printer sharing is another option. When we enable file and printer sharing, files and
printers that we have shared on our computer can be accessed by other users on the network. With this type of
sharing we have more control over who we share our files with on the network.
The Public folder sharing option enables network users to access our public folder. Public folders can be read
and written to by all users. Even network users will be able to write files to our public folder. Files shared with
266
Security
Advanced Sharing Settings in Windows 7
public folder sharing are found in the C:\Users\Public folders. Public folder sharing is more simple and
quicker, but we can't set permissions for individual users (all users have access).
Another option is Media streaming. When media streaming is on, people and devices on the network will be
able to access pictures, music and videos on our computer. Also, our computer will be able to find media
resources on the network. In Media streaming options we will be able to name our media library, choose on
which networks to share, and what type of media to share.
Figure 436 - Media Streaming
Figure 437 - Media Streaming Options
File sharing connections option allows us to protect share connections using a 128-bit encryption, or 40- or 56bit encryption for legacy devices.
267
Security
Advanced Sharing Settings in Windows 7
Figure 438 - Work Profile Part 2
The Password protected sharing option means that only users which have a user account and password on our
computer can access our shared files and printers, and Public folders. If we want to give other users access,
we'll have to turn off this option.
The HomeGroup connections option is only available in the Home Network profile. It determines how
authentication works for HomeGroup resources. HomeGroup is a simple way to manage sharing and
authentication on Home networks running Windows 7. If all computers in the HomeGroup have been
configured with the same usernames and passwords, we should choose the "Allow Windows to manage
homegroup connections" option. However, if we have different users and passwords on each computer, we
should use the second option.
268
Security
Working With Shared Folders in Windows 7
Working With Shared Folders in Windows 7
Before you start
Objectives: learn how to configure basic sharing, advanced sharing, how to access shared folders using UNC,
and which command line utility can be used to configure shares.
Prerequisites: you have to know what NTFS and Share permissions in Windows are, and how to configure
NTFS permissions in Windows 7.
Key terms: shared folders, network share, advanced sharing, basic sharing, net share command.
Shared Folders
As you know, in Windows 7 we can set up Shared Folders in three different ways: Basic, Advanced and Public
folder sharing. We will now see how that works. For the purpose of this article we will create a folder named
"demo" on our Desktop. Next, we will right click it, select its Properties, and then open the Sharing tab.
Figure 439 - Sharing Tab
269
Security
Working With Shared Folders in Windows 7
Notice that we can see two Sharing sections on this tab. The first section is named Network File and Folder
sharing. Here we have a Share button which will take us to the Basic sharing options. On the Advanced Sharing
section we can click on the Advanced Sharing button which will take us to advanced options.
Basic Sharing
To edit Basic sharing options we simply click on the Share button in the first section.
Figure 440 - Basic Sharing
Basic Sharing
This interface is a bit simpler than in Advanced Sharing. Here we can choose the users and groups and then
add them to the list. When we click Add, we can then change Permission Level by choosing appropriate
permission from the list.
Figure 441 - Basic Permissions
Notice that we can only give Read and Read/Write permissions. Owner permission is set for the user who
created the share.
When we click the Share button, we will get a UNC path to the shared folder which we can then copy and send
to other users. They will have to enter the whole path to access our shared folder.
270
Security
Working With Shared Folders in Windows 7
Figure 442 - Share Path
To stop sharing folder in this Basic configuration, simply right-click shared folder, select the "Share with"
option, and then select "Nobody".
Right-Click Sharing
We can also share any folder by right-clicking it and then selecting the "Share with" option.
Figure 443 - Share With option
This way we can share folder directly to a HomeGroup with Read or Read/Write permissions. We can also
choose the "Specific people" option which will take us to the Basic Sharing screen that we already saw above.
Advanced Sharing
Advanced Sharing is the original way of sharing things in Windows and administrators will almost always want
to use this method of sharing.
Let's click on the Advanced Sharing button. We will enter the "demoshare" as our share name (the share name
can be different from the name of the folder).
271
Security
Working With Shared Folders in Windows 7
Figure 444 - Advanced Sharing
Notice that here we can limit the number of simultaneous users here, and that we can edit permissions and
caching options. Let's check out Permissions by clicking on the permissions button.
272
Security
Working With Shared Folders in Windows 7
Figure 445 - Permissions
Notice that the Everyone group by default has Read permission on shared folders. Here we can now add other
users or groups and set their Share permissions.
Let's click on the OK buttons and check our shared folder in Windows Explorer. To do that we will enter the
UNC path to our share. Our computer name is WIN-7-VM and we know that the share name is "demoshare".
The UNC path syntax is \\computername\sharename. So, the UNC path to our share is \\WIN-7VM\demoshare. To check your computer name you can go to System properties (right-click your computer
icon and select Properties option). Let's enter the UNC path to our WIN-7-VM computer to see all shared
folders.
Figure 446 - Shares
273
Security
Working With Shared Folders in Windows 7
Note that we can see our demoshare folder and the Users folder. We see the Users folder because this is where
the Public folder is located. Now, what if we want to share some folder but we don't want it to be visible to all
users? To do that we can use Administrative Share. To configure administrative share, we simply put the $ sign
after the share name. For example, let's add another share name to the same folder but this time with the $ at
the end. The added share name will be "demoadmin$". To add another share name, we simply click on the Add
button on Advanced Sharing window. When we Add new share, we will get a new window to enter options.
Figure 447 - Add Share
When we click OK, the "demoadmin$" will be added to the list of share names.
Figure 448 - Share Name List
Let's now check the \\WIN-7-VM.
Figure 449 - Shared Folders
Notice that the "demoadmin$" is not listed, and that's great. We can still access that share by entering the
whole UNC path manually: \\WIN-7-VM\demoadmin$.
274
Security
Working With Shared Folders in Windows 7
Now, remember that share permissions and NTFS permissions work together. The most restrictive permission
is the effective permission. Administrators sometimes give Full control to Everyone group in share
permissions, and then manage user permissions using NTFS permissions. This way administrators manage
permissions from one location.
File Sharing Wizard
We can also create shares using File Sharing Wizard in Computer Management console (right-click Computer
icon and select Manage option). In Computer Management we will navigate to the Shared Folders. Here we can
see all shares that are configured, active sessions and open files. Here we will see all folders that are configured
using the Advanced configuration that we described earlier. Here we can also add new shares. To do that
simply right-click and select New Share, and then follow the wizard.
Shares in Command Line
In command line we can use the net share command to work with shares. Remember, we first have to run
CMD as administrator (right-click > Run as administrator). To list all configured shares we can simply
enter net share command.
Let's say that we want to share a folder located in C:\Docs. The share name will be "docs". We will give Kim
Verson read permission on that share. The whole command to do all that would be net share docs=c:\Docs
/grant:"Kim Verson",READ
Figure 450 - Net Share command
To delete that share we can enter the command net share docs /delete. For the full syntax of the net share
command enter net share /?.
275
Security
HomeGroups in Windows 7
HomeGroups in Windows 7
Before you start
Objectives: Learn how to create, how to join, and how to edit HomeGroup in Windows 7.
Prerequisites: you have to know what is sharing and what is HomeGroup in general.
Key terms: HomeGroup, Windows 7, sharing, libraries, permissions
HomeGroup
We can use HomeGroup feature in Windows 7 to simply share data between multiple computer in a home
network. Have in mind that we can only have one HomeGroup per LAN network. So, it's basically designed
for home environments. Only members of the HomeGroup will have access to shared data. HomeGroups are
protected with password.
To create a HomeGroup, we can go to Control Panel > HomeGroup. We will get the following screen.
Figure 451 - Create a HomeGroup
If a HomeGroup already exists on the network, we will see it on this screen. Then we will be able to join that
existing HomeGroup. So, on this screen we can click on the "Create a homegroup" button. Another way
HomeGroup is typically created is when you change a location for your network to the "Home network". Go
to the Network and Sharing Center and try to change the location for your network to the Work network, and
then back to the Home network. When you do that, you will get the following screen.
276
Security
HomeGroups in Windows 7
Figure 452 - Select What to Share
This screen is the same one when we try to create HomeGroup in Control Panel. So, all we have to do is select
what we want to share. In our case we will select all options except documents. Once the HomeGroup is
created, we will see a HomeGroup password.
Figure 453 - HomeGroup Password
We should save this password in secure place. The password is case sensitive. When we click Finish, the
HomeGroup will be created. Now, we can go to our Computer and select Homegroup from the menu. If no
one joined our homegroup, we will see the following screen.
277
Security
HomeGroups in Windows 7
Figure 454 - Empty HomeGroup
People on other computers will see a screen like this when they open HomeGroup.
Figure 455 - Join HomeGroup
When users join existing Homegroup, they will also have to specify things they want to share. Also, users will
have to enter the password for the Homegroup in order to join it. Once they join the Homegroup, they will
start seeing things from users on the homegroup under the Homegroup section in Windows Explorer.
Figure 456 - HomeGroup in Windows Explorer
As you can notice, we actually share libraries in HomeGroup. As you should know, by right-clicking on specific
library, we can specify how we want to share them. We can specify if we'll only give read permissions or
Read/Write permissions for Homegroup users.
278
Security
HomeGroups in Windows 7
Figure 457 - Setting Permissions for Homegroup
If we give Read/Write permission, users from other computers will be able to edit existing and create new files
on our computer. We can also create our own custom libraries and share them on HomeGroup.
To change HomeGroup settings, we can always go to the Control Panel > HomeGroup.
279
Security
Configuring Auditing in Windows 7
Configuring Auditing in Windows 7
Before you start
Objectives: Learn how to enable auditing in Windows 7, and how to select auditing entries in folder
properties.
Prerequisites: you have to know what auditing is.
Key terms: auditing, Windows 7, configuration
Group Policy
In order to manage auditing, the first thing we have to do is go to our Group Policy editor. To do that we can
enter "gpedit.msc" in search, and open the gpedit program. Next, we have to navigate to Computer
Configuration > Windows Settings > Security Settings > Local Policies > Audit Policy.
Figure 458 - gpedit
Here we can see all auditing policies. In our case we will try to audit files and folders. For that we will select the
"Audit object access" policy and select the Success and Failure options.
Figure 459 - Audit Object Access
280
Security
Configuring Auditing in Windows 7
The next step is to select the folder which we want to audit. For this demo, we have created C:\Docs folder.
Inside of Docs we will have Admin Data and User Data folders. We have configured security settings in a way
that all users can create data in User Data folder, but they can't delete them.
Figure 460 - Docs Folder
Now let's go to the Properties of the User Data folder, then Security tab > Advanced button, and then the
Auditing tab. Click the Continue button to in order to see auditing properties.
Figure 461 - Auditing
Here we will click the Add button, and enter the Authenticated Users object.
281
Security
Configuring Auditing in Windows 7
Figure 462 - Auditing Object
When we click OK, we will be asked to select auditing entries. In our examples we will select Successful and
Failed Delete options.
Figure 463 - Auditing Entries
Now that we have set up auditing, we have to wait for our users to take actions. After some time, we can check
Event Viewer to see if there were successful or failed auditing events. All audit events are stored in the
Windows Logs > Security. In our case we have logged on with user Kim Verson, and tried to delete a file in
User Data folder, so let's see how we can find this in Event Viewer. In our case we had to use Filter and Find
option to find appropriate entry shown on the picture below.
282
Security
Configuring Auditing in Windows 7
Figure 464 - Kim Verson Entry
In the details of the event we can see that the user Kim Verson tried to delete a file from User Data folder, but
that action was restricted. As you can see, there are many more auditing events listed. Be sure to check out at
least some of them.
Advanced Auditing Features
When compared to previous versions of Windows, in Windows 7 we have some more advanced auditing
options. To check them out we have to go to Group Policy editor > Windows Settings > Advanced Audit
Policy Configuration. Here we have more granular control of our auditing options.
283
Security
Configuring Auditing in Windows 7
Figure 465 - Advanced Auditing
Advanced Auditing can give us better view of what's going on our computer.
284
Security
Encrypting File System in Windows 7
Encrypting File System in Windows 7
Before you start
Objectives: Learn how to encrypt file or folder, how to designate recovery agents, and how to generate selfsigned keys.
Prerequisites: you have to know what Encryption File System is in general.
Key terms: EFS, Encrypting File System, configuration, Windows 7, Recovery Agent, certificates
How to Enable EFS
For this demo we have created a sample directory named "EFS-demo" on our C drive. If we check NTFS
permissions on that folder, we will see that Authenticated Users group has the Modify permission set. This
means that anyone can create and modify files in that directory.
Figure 466 - NTFS Permissions
On our computer we have a user named "Kim Verson". If we log on with that user account, we can create a
file in a EFS-demo folder. That's because all authenticated users have the permission to work in that folder. For
this demo, Kim Verson will create a file named "Verson CV.txt".
285
Security
Encrypting File System in Windows 7
Figure 467 - Verson CV File
The next thing we will do is encrypt that file. To do that we have to go to the properties of the file, and click on
the Advanced button on the General tab. This will open the Advanced Attributes window.
Figure 468 - Advanced Attributes
Here we have to select the "Encrypt contents to secure data" option. When we click OK, the system will
prompt us to encrypt the whole folder. Since we are encrypting a specific file, the parent folder will remain
unencrypted, so any files that we put in the folder will remain unencrypted. The recommended practice is to
encrypt folders, and not files. When we encrypt folder, and file that we create in that folder will automatically
be encrypted.
286
Security
Encrypting File System in Windows 7
Figure 469 - Warning
For this demo we will only encrypt the file, and not the folder. Notice that the Details button is grayed out. It
will become available when we encrypt our file. When we click OK, the color of our file will change to green,
indicating that our file is now encrypted. Also, we will get a prompt to back up our encryption key.
Figure 470 - File Color
Figure 471 - Backup Prompt
Keep in mind that when we are not in a domain environment, our computer will locally generate certificates for
EFS encryption. That's why it is very important to back up our encryption keys.
So, to recap, Kim Verson created the file "Verson CV" in a folder accessible by all users on the computer. Kim
encrypted that file, and because of that, other users won't be able to access it, despite of NTFS permissions.
Let's try this now. We will log on as a different user and try to open Verson CV file.
287
Security
Encrypting File System in Windows 7
Figure 472 - Access Denied Message
As we can see, the access to the file is denied to other users. So, each user can encrypt their own files, and other
users won’t be able to open them, despite all NTFS permissions.
EFS Certificates
EFS certificates for each user are created when the user first encrypts some file. In local environment, each
certificate is stored locally within the users’ profile. This means that if we copy our encrypted file to another
computer, we won’t be able to open them (since there is no EFS key for our user on the other computer). In
order to be able to open our encrypted files on other local computers, we have to export our private keys and
import them on other computers.
Let's add another file called Marko CV to the same folder and encrypt it. If we open properties of our
encrypted files and open the Advanced Attributes, we'll notice that now we can click the Details button. When
we do that, we will see the list of users who can access the file.
288
Security
Encrypting File System in Windows 7
Figure 473 - List of Users
Notice that here we have an Add button. With this we can add more users to the list of users who can access
our files. When we click the Add button, we will be presented with the list of user certificates. We have to
select the certificate of the user to which we want to allow access.
289
Security
Encrypting File System in Windows 7
Figure 474 - List of Certificates Available to Select
So, we can share an encrypted file with multiple users, as long as we have access to their certificates. Keep in
mind that other users will be able to provide access to other users as well.
Recovery Agent
By default, in Windows 7 there is no default recovery agent designated in local environments. There is no single
user which can access all files. To create a recovery agent, we first must generate a pair of recovery keys. To do
that, we will open CMD as Administrator. In CMD, we will run the "cipher /r:RecoveryAgent" command. In
our case we have logged on to our computer as an Admin user which is a member of the Administrators group.
Figure 475 - Cipher Command
290
Security
Encrypting File System in Windows 7
We will have to enter the password which will be used to protect our generated files. With this we get a selfsigned local certificate and a local private key certificate with the name of "RecoveryAgent". The next thing to
do is to import those keys into local Group Policy. To do that, we will open local group policy (enter
gpedit.msc in search) and go to Computer Configuration > Windows Settings > Security Settings > Public Key
Policies > Encrypting File System. Next, we have to right-click the Encrypting File System and select the Add
Data Recovery Agent option.
Figure 476 - Add Recovery Agent Option
The wizard will open. On the Select Recovery Agents screen we have to browse to our generated certificates in
EFS-demo folder. When we select our certificate we will get a warning that Windows can't determine if the
certificate has been revoked. This is because this is a self-signed certificate, so we can click Yes in this case.
When we do that, we will see our certificate in the list.
Figure 477 - Certificate Selected
When we click Next and Finish, we will see our Recovery Agent certificate in the Encrypting File System node.
This certificate will allow our Admin user (we have created this certificate with the Admin user) to recover
encrypted files as well.
291
Security
Encrypting File System in Windows 7
Figure 478 - Certificate Added
We can add multiple recovery agents (different users). All we have to do is generate keys while logged on as a
specific user.
When we have designated our recovery agents, we have to run the "cipher /u" command in order to update all
encrypted files with the designated recovery agents. We will enter that command as Admin user.
Figure 479 - Cipher Update Command
Notice that Marko CV file was updated (file created by Admin), while the Verson CV file couldn't be
decrypted. To decrypt Verson CV file we have to log on as Kim Verson and then run the cipher /u command
again. We have to do that for all user accounts. This is because we have created Recovery Agents after the users
have already encrypted their files. That's because it is best to designate recovery agents before users start to
encrypt their files. That way recovery agents will be added automatically, so we don't have to run cipher /u
command.
Backing up Keys
It is very important to back up EFS keys. There are two ways to do that. We can click on the prompt to back
up our key. We can also go to Control Panel > User Accounts and click on the "Manage your file encryption
certificates" option. When exporting certificates we will be able to choose the format. We should export all
certificates in the certification path.
292
Security
Encrypting File System in Windows 7
Figure 480 - Export Options
On the next screen we will have to enter our password for the exported certificates, to keep them secure.
Figure 481 - Password for Exported Files
We will also have to specify the location of the exported file. We should always copy this file and keep it in a
safe place. Make sure that you know the location and the password for exported certificates.
Figure 482 - Location for Exported Files
Another way to work with certificates is the Certificate Snap-in in the MMC console. We can also export our
keys from there.
293
Security
Configuring BitLocker in Windows 7
Configuring BitLocker in Windows 7
Before you start
Objectives: Learn how to configure BitLocker in Windows 7 without a TPM chip available.
Prerequisites: you have to know what BitLocker is.
Key terms: BitLocker, configuration, Windows 7, TPM
BitLocker Configuration
The first requirement for BitLocker is that our computer should have a TPM chip installed on the
motherboard. The TPM chip must be enabled in the BIOS. After that we can go to the BitLocker
configuration in Windows. We can find BitLocker in Control Panel, and the screen looks like this.
Figure 483 - BitLocker Screen
As we can see, here we can turn on BitLocker. When we click that option, the BitLocker wizard will appear.
The thing is, in our case, our computer doesn't have a TPM chip installed. If that's the case, we will get the
following message.
Figure 484 - TPM Missing Message
However, we can still enable BitLocker, even if we don't have a TPM chip. To do that, we have to configure
some Group Policy options. So, let's open group policy editor by entering "gpedit.msc" in search, and allow
BitLocker configuration without TPM. Keep in mind that for this to work we have to have a removable USB
key available to store the recovery key information. In Local Group Policy Editor we will go to Computer
Configuration > Administrative Templates > Windows Components > BitLocker > Operating System Drives.
Here we will select "Require additional authentication at startup" policy. We will enable this policy and also
select the option "Allow BitLocker without a compatible TPM".
294
Security
Configuring BitLocker in Windows 7
Figure 485 - BitLocker without a TPM
When we click OK, we can go back to the BitLocker configuration in Control Panel. This time we will see a
different screen, like this.
Figure 486 - Startup Options
Note that now we can select the "Require a Startup key at every startup". Before we select that option, we
should have a USB flash drive inserted, on which the startup key will be stored on. So, when we move on, we
will select the USB key (ROKI (E:) in our case).
Figure 487 - USB Disk Selection
295
Security
Configuring BitLocker in Windows 7
The startup key will be saved on the USB disk, but on the next screen we will be given an option to save the
recovery key as well. We can also print the recovery key, which will look something like this.
Figure 488 - Recovery Key Storage
In our case we will also save the recovery key to the USB flash drive. On the next screen we will have an option
to run BitLocker system check, which will ensure that BitLocker can read the recovery and encryption keys
correctly before encrypting the drive. When we click the "Start Encrypting" button, the encrypting process will
begin, but we will be able to continue working until the process finishes. From this point on, to turn on our
computer we will have to have a USB drive with the startup key inserted in our computer.
When the encryption finishes, we will get two more options on the BitLocker window in Control Panel. As we
can se, we can now suspend protection and we can manage BitLocker.
Figure 489 - BitLocker Options
The Suspend Protection option won't decrypt back the drive, it only pauses the protection so that we can make
certain boot changes if we need to, and then reconfigure the BitLocker. If we click the Manage BitLocker
option, we will see options to Save or print our recovery key again, or to duplicate the startup key.
Figure 490 - Manage BitLocker
296
Security
Configuring BitLocker in Windows 7
If we try to boot without our startup key (USB stick removed), we will get the following message.
Figure 491 - BitLocker Warning
To fix this, we have to enter the USB flash drive, and then hit the Escape key.
Configuring Recovery Agents
When configuring recovery agents, the firt thing we have to do is to generate a set of recovery keys. To do so,
we will open command line. In our case, we have logged on with the Admin user and we will generate keys for
that user. In CMD we will enter the command: "cipher /r: RAAdmin". The name of the file will be
"RAAdmin". After that we will have to type in the password to protect our PFX file.
Figure 492 - Cipher Command
Keep in mind that your files will be created in your current working directory. The next thing we have to do is
load our certificates. To do that we will open Local Group Policy Editor and navigate to Computer
Configuration > Windows Settings > Security Settings > Public Key Policies > BitLocker Drive Encryption.
To add the recovery agent, we will go to Action (or right-click "BitLocker Drive Encryption), and then select
"Add Data Recover Agent.
297
Security
Configuring BitLocker in Windows 7
Figure 493 - Adding Data Recovery Agent
The Wizard will appear. In the Wizard we will first have to browse for the folder where we have saved our
certificate file that we have created using cipher command.
Figure 494 - Certificate Selected
So, the certificate actually designates the user account. We are taking this certificate for this user account, and
specifying it as the recovery agent. In that way, this user account will be able to recover BitLocker enabled
drives.
Figure 495 - List of Users
In Active Directory environment, we would get these certificates from Active Directory Certificate Server. That
way a single user account can be used on any computer in the environment to recover BitLocker encrypted
drive. This way we can even install hard drive from one machine to another and use the recovery agent to
recover files from BitLocker encrypted drive.
298
Security
Configuring BitLocker in Windows 7
The next thing to do is to configure group policies for BitLocker. To do that, in Local Group Policy Editor we
will navigate to Computer Configuration > Administrative Templates > Windows Components > BitLocker
Drive Encryption. We will edit the policy named "Provide the unique identifiers for your organization". Here
we can specify the identifier that will be inserted into the BitLocker drive every time a new drive is
encrypted. When we set this, the DRA will only be able to unlock drives that have this identifier. Under other
sections we can configure how our drives can be recovered. For example, under Operating System Drives
section, we will configure the "Choose how BitLocker-protected operating system drives can be recovered"
policy. In our case we will enable this policy and select the "Allow data recovery agent" option. This way, the
recovery agent we specified earlier will be able to recover BitLocker-protected operating system drive. We
should do the same thing with other types of drives.
Figure 496 - DRA Enabled
Once we set this policies, we will be able to recover BitLocker-protected drives using the specified recovery
agent (Admin user in our case), in case the encryption keys are lost. Keep in mind that this is the first step we
should take before we start to use BitLocker, especially in Active Directory environment. In case we already
started using BitLocker on some drives, we can run the "manage-bde -setidentifier {drive letter}" command
to update encryption information on those drives. In our case we will update our C: drive.
Figure 497 - Setting Identifier on C:
To restore a locked drive, we can use the -unlock switch together with the manage-bde command.
299
Security
Configuring BitLocker to Go in Windows 7
Configuring BitLocker to Go in Windows 7
Before you start
Objectives: Learn how to configure BitLocker to Go on USB flash drive on Windows 7.
Prerequisites: you have to know what BitLocker is.
Key terms: BitLocker To Go, BitLocker, configuration, Windows 7, USB flash drive.
Prerequisites
Before we start using BitLocker, we will format our USB flash drive using FAT32 file system and the default
allocation unit size. Also, before we start using BitLocker, we should have our Data Recovery Agents (DRAs)
configured. Next, we will open Local Group Policy Editor by entering gpedit.msc in search. Here we will
configure some local policies related to BitLocker To Go. We will navigate to Computer Configuration >
Administrative Templates > Windows Components > BitLocker Drive Encryption. Here, the first thing we
can do is set up unique identifiers for our organization. This setting will allow us to specify unique string that
will be written on BitLocker devices.
Figure 498 - Unique Identification Policy
In our case we have simply entered UtilizeWindows as our identifier. This will allow us to restrict people from
being able to access or DRAs from being able to recover devices and drives that don't have this unique ID on
it. We can enter multiple IDs. After that we will go to the Removable Data Drives section. Here we will enable
the Allow access to BitLocker-protected removable data drives from earlier versions of Windows.
300
Security
Configuring BitLocker to Go in Windows 7
Figure 499 - Allowed Access on Earlier Versions of Windows
By doing this, users can take the USB drive and plug it in to Windows XP or Vista machine and be able to
access it. Next thing we can do is to enable Deny access to removable drives not protected by BitLocker. We
can also choose to deny write access to devices configured in another organizations.
Figure 500 - Deny Write Access
With this we are restricting our computers to have write access to a USB flash drive that has not been
encrypted with BitLocker with our own organization ID. That means that we can't bring someone BitLocker
enabled drive from someone else and use it. The next thing we will do is enable the Configure use of
passwords for removable data drives policy. We will select the “Require password for removable data drive”
option.
301
Security
Configuring BitLocker to Go in Windows 7
Figure 501 - Password Policy
Control Panel
Now that we have some basic policies set, we can go to Control Panel and turn on BitLocker for our USB
drive. In our case, our USB flash drive is ROKI (E:).
Figure 502 - USB Drive
Next, we will be able to choose the way to unlock the USB flash drive. In our case we have the password
option set (because of policy settings), so we will enter our password.
302
Security
Configuring BitLocker to Go in Windows 7
Figure 503 - Unlock Option
On the next screen we will have the option to save and print our recovery key. This step is very important for
recovery purposes.
Figure 504 - Recovery Option
On the next screen we will start the encryption process. Once our USB flash drive is encrypted, we can start
using our drive. When we plug it out and then back in, in Control Panel we will see that the USB drive is
locked.
Figure 505 - Locked Drive
When we try to open our USB drive from the Explorer, we will see a window in which we can enter the
password to unlock the drive.
303
Security
Configuring BitLocker to Go in Windows 7
Figure 506 - Unlocking Drive
Note that we can save our password so that our USB drive is automatically unlocked when we plug it in. Once
we click Unlock, we will have full access to our USB drive. We can manage BitLocker settings on our USB
drive now in Control Panel. We can change the password used to unlock the drive, save the recovery key again,
etc.
Figure 507 - Management Options
304
Security
Windows Defender in Windows 7
Windows Defender in Windows 7
Before you start
Objectives: Learn where to find and how to configure Windows Defender in Windows 7.
Prerequisites: you should know what Windows Defender is in general.
Key terms: Windows Defender, Windows 7, configuration, options.
Windows Defender
In Windows 7, Windows Defender is integrated into Action Center, and this enables consistent alerts when
certain actions are required related to Windows Defender. We can find Windows Defender in Control Panel, or
we can simply search for it using Search in Start menu.
Figure 508 - Windows Defender
First thing we can do is to configure quick scan, full scan or custom scan.
Figure 509 - Scan Options
If we do a custom scan, we can choose the location we want to scan.
305
Security
Windows Defender in Windows 7
Figure 510 - Custom Scan
We can choose to scan certain drives, but also certain folders or USB flash drives. Once the scan is complete
we will see the scan statistics. If we choose the quick scan, it will search in important folders only, like the
system folder and check certain registry keys.
On the Tools menu we can configure Windows Defender options. We can enable or disable automatic
scanning.
Figure 511 - Options
By default, our computer will be scanned at 2 AM. We can also choose to check for updated definitions before
scanning.
306
Security
Windows Defender in Windows 7
We can also specify other options like default actions, real-time protection, excluded file types, etc. For default
actions, we can choose what will happen when certain items are detected. We can choose to remove it or
quarantine it or we can leave it to "recommended action based on definitions".
Figure 512 - Default Actions
Real-time protection is enabled by default, but we can choose which security agents we want to run.
Figure 513 - Real-time Protection Options
We can exclude files and folders from being scanned. We can also exclude files based on file type. There are
also some advanced options we can set, like if we want to scan within archive files, e-mails, and removable
drives. We can also choose if we want to use heuristics and create restore points.
307
Security
Windows Defender in Windows 7
Figure 514 - Advanced Options
If we go back to the Tools menu, we can see that we can manage quarantined items, and view items that we
have allowed.
Figure 515 - Tools and Settings Menu
In the Quarantined items we will see items that have been recognized as malicious. In the Allowed items we
will have items that were recognized as malicious, but the user allowed them, so they are not monitored any
308
Security
Windows Defender in Windows 7
more. Sometimes, apps that are legit may seem as malware to Windows Defender, and that's why we have an
option for allowed items.
309
Optimization
Monitoring Resources in Windows 7
Optimization
Monitoring Resources in Windows 7
Before you start
Objectives: Learn how to use Task Manager and Resource Monitor to see how your system resources are
being used.
Prerequisites: you have to know what system performance is in general.
Key terms: performance, Windows 7, Task Manger, Resource Monitor, process
Task Manager
Task Manager can easily be opened by pressing the CTRL+SHIFT+ESC keys. We can also start it by rightclicking Taskbar and selecting the Start Task Manager option.
Figure 516 - Task Manager
Task Manager will show us all the processes running for current user. We can click the "Show processes from
all users" if we want to see all processes running on the system. We can click on the column name to order the
list by that column. We can also set process priority and affinity by right-clicking particular process.
310
Optimization
Monitoring Resources in Windows 7
Figure 517 - Priority
Note that priority can be: real-time, high, above normal, normal, below normal, and low. The priority controls
how the system can delay or switch between processes. With affinity we can select processors (or processor
cores) that are allowed to run selected process.
Figure 518 - Affinity
On the Processes tab we can also end (kill) a process. We do that by selecting a particular process and then
clicking the End Process button.
We can also use Task Manager to start or stop running application. We can do that on the Applications tab.
Note that not every software program or process will be shown on the Applications tab. Typically, applications
that are started by the user, and applications shown on the Taskbar will be shown on the Applications tab.
311
Optimization
Monitoring Resources in Windows 7
Figure 519 - Application Tab
On the Services tab we can see a list of services on our computer, and their status. From here we can also start
or stop particular service by right-clicking it. We can also view the process (in the Processes tab) associated
with the service.
312
Optimization
Monitoring Resources in Windows 7
Figure 520 - Services Tab
If we want more control over our services, we should go to the Services console. We can do that by clicking on
the Services button from here.
On the Performance tab we can check the performance of our computer.
313
Optimization
Monitoring Resources in Windows 7
Figure 521 - Performance Tab
Here we can use the percentage of CPU usage at the moment and also usage history from past few minutes. In
our case we have multiple (four) cores, so we see four graphs, one for each core. On this tab we can also see
current memory usage and memory usage history for the last few minutes. If the CPU Usage History graph is
showing 100 percent, it can mean that some program might not be responding or is over using CPU
resources. If the Memory graph is consistently high, it can mean that we have too many applications opened at
the same time. As a temporary solution, we can quit some running programs to decrease the demand for RAM.
However, the only long-term solution is to add more physical RAM. Also, we could try implementing the
ReadyBoost feature.
Below CPU and memory graphs, we can see details about memory and resource usage. In the Physical Memory
section we can see the total amount of RAM installed, and also the amount of RAM recently used for system
resources (Cached). Here we also see amount of Available and Free memory. In the Kernel Memory section we
can see the total amount of memory being used by the core part of Windows called the Kernel. The used
virtual memory is shown on the Paged amount, while the Nonpaged amount shows the amount of RAM used
by the Kernel. In the System section we can see 5 values related to Handles, Threads, Processes, Up Time, and
Page File Handles (Commit). These are all pointers that refer to system elements such as files, directories,
registry keys, events, etc.
314
Optimization
Monitoring Resources in Windows 7
On the Networking tab we can see network usage. Utilization is listed as a percentage of the total available
theoretical bandwidth (such as 100 Mbps for a Fast Ethernet connection).
Figure 522 - Networking Tab
On the Users tab we can see logged on users on our computer, and their login method. From here we can
Disconnect or Logoff listed users.
315
Optimization
Monitoring Resources in Windows 7
Figure 523 - Users Tab
If we go back to Performance tab, note that we can run Resource Monitor from here.
Resource Monitor
The Resource Monitor is more enhanced tool for checking out performance and resources on the
computer. We can enter also enter resmon.exe in Search to start the Resource Monitor.
316
Optimization
Monitoring Resources in Windows 7
Figure 524 - Resource Monitor
On the Overview tab we can see performance for our four major system components and resources. Those are
CPU, Disk, Network, and Memory. On the CPU section we see a list of processes, their description, status,
number of threads, etc. We can click on the particular column to sort the list based on that column.
On the Disk section, we can see which processes are using our disks. We can see which process reads or writes
which amount of data, and the total usage. We can also see the file that is doing the most amount of reading
and writing to.
On the Networking section, we can see the amount of traffic coming and going to our machine and what
services or applications are using it.
Figure 525 - Network Section
On the Memory section, we can see what applications and services are using the most memory.
317
Optimization
Monitoring Resources in Windows 7
Figure 526 - Memory Section
Now each mentioned resource also has a separate tab. Each tab allows us to view the processes and certain
information about that process. We can filter the results according to the processes or services that we want to
monitor. For example, we'll go to the CPU tab and select the permon.exe process. Note that services,
associated handles (registry keys and files), and associated modules (DLLs and executables) are now filtered by
perfmon.exe. So, this way we can check all this for specific process.
318
Optimization
Monitoring Resources in Windows 7
Figure 527 - Filter Mode
While we are in the filtered mode, only resources that are used by the selected process or service, are displayed
on all other tabs. So, if we go to the Memory tab, we will also see the information filtered by the perfmon.exe.
319
Optimization
Monitoring Resources in Windows 7
Figure 528 - Memory Tab
The same thing is on the Disk tab. We will see files that the selected process is reading and writing to. On the
Network tab we will see the network activity is performed by our selected process (TCP connections and
listening ports).
320
Optimization
Using Reliability Monitor in Windows 7
Using Reliability Monitor in Windows 7
Before you start
Objectives: Learn how to open and use Reliability Monitor in Windows 7.
Prerequisites: you have to know what Reliability Monitor is.
Key terms: Reliability Monitor, Windows 7
Reliability Monitor
To find open Reliability Monitor, we can enter "perfmon /rel" in Search box. The Reliability Monitor monitor
shows us information about the application, Windows, and misc failures, as well as other warnings and
information.
Figure 529 - Reliability Monitor
Note that in our case we have one failure (marked with red x icon) in the Application failures row. Also, we
have info icons for every day. If we look at the bottom of the window, we will see more detail about the events
on the selected day.
321
Optimization
Using Reliability Monitor in Windows 7
Figure 530 - List of Events on Specific Day
On the Action column we can check for solutions or view technical details about our events.
Note that not all days are visible on the graph. To go back in time, we can click on the left arrow. We can go
back up to one year. Also, we can change the view by days or weeks. The great thing about Reliability Monitor
is that we can see what happened and when it happened on our system. Prior to Windows 7 we couldn't do
that without searching multiple logs in the Event Viewer.
Note that in our case we had several critical events on the 24 of March 2015. We also had several installation
and configuration events. The Reliability Monitor also gives us a stability scale. If we have errors, the stability
index will start to come down. Any change you make to your computer or problem that occurs on your
computer affects the stability index. In our case the stability index is rising, since we didn't have any critical
events for several days.
322
Optimization
Using Reliability Monitor in Windows 7
Action Center in Windows 7
Before you start
Objectives: Learn where to find and how to use Action Center in Windows 7.
Prerequisites: you have to know what is Action Center in Windows.
Key terms: Action Center, Windows 7.
Action Center
One of the important tool to help us troubleshoot our system is the Action Center. The Action Center icon is
available in the Taskbar notification area (icon is marked yellow on the picture).
Figure 531 - Action Center Icon
When we click the icon, we will see the current status. In our case we have 3 important messages. We can click
on the "Open Actin Center" to see more details.
323
Optimization
Using Reliability Monitor in Windows 7
Figure 532 - Action Center
We can see different items grouped together, In our case we have one Security item (Firewall status), and two
maintenance items (problem with Adobe Reader, and backup).
Action Center will propose actions to resolve problems. For example, for the backup problem the solution is to
set up backup. For a problem with Adobe Reader, we can see message details. For Firewall we could enable it,
but this option is disabled by the system administrator in our case, since Firewall is installed and managed
elsewhere.
The typical and most important things in Action Center is the Security section. Action Center will warn us if we
have problems with virus protection, Windows Update, Firewall and malware.
We can disable all messages if we want, in the Action Center settings (link to settings is available in the left
324
Optimization
Using Reliability Monitor in Windows 7
Figure 533 - Action Center Settings
325
Optimization
Visual Effects and Paging File Options in Windows 7
Visual Effects and Paging File Options in Windows 7
Before you start
Objectives: Learn where to find and how to configure visual effects and paging file settings in Windows 7.
Prerequisites: you should know about optimization in Windows in general.
Key terms: optimization, performance, visual effects, paging file settings, Windows 7
Performance Options
To change the performance settings, we can go to the properties of our computer. To do that, we can rightclick Computer and then choose the Properties option.
Figure 534 - Computer Properties Option
Next, we have to go to Advanced System Settings.
326
Optimization
Visual Effects and Paging File Options in Windows 7
Figure 535 - Advanced System Settings Link
Next, we have to go to Performance Settings.
Figure 536 - Performance Settings
We well now see a Visual Effects tab. By default all of the visual settings are enabled. If we have a machine
with weaker hardware, we can select the "Adjust for best performance" option, or we can start unchecking
specific boxes to increase the performance of the machine.
327
Optimization
Visual Effects and Paging File Options in Windows 7
Figure 537 - Visual Effects Options
Overall this will make the system a little bit more responsive as it will be using less graphical power.
On the Advanced tab, we can configure Processor Scheduling. We can choose if we want to adjust for best
performance of programs or background services.
328
Optimization
Visual Effects and Paging File Options in Windows 7
Figure 538 - Advanced Tab
Usually on desktops that are running programs we will choose the "Programs" option, but on servers or certain
desktops that are doing a lot of background applications like SQL databases, we would choose the
"Background services" option.
On this tab we can also configure the virtual memory of our computer. To do that we click on the Change
button on the Virtual Memory section.
329
Optimization
Visual Effects and Paging File Options in Windows 7
Figure 539 - Virtual Memory Options
By default Windows 7 configures Virtual Memory automatically. If we uncheck the "Automatically mange
paging file size for all drive", we will be able to change those settings. We can specify a custom value in MB.
We can set the initial size and a maximum size. It is recommended to specify a value one and a half times the
amount of physical memory we have. We can actually see the recommended values at the bottom of this
window. We can put the same value for initial and maximum size.
Also, if our computer has more than one physical separated disk it might be beneficial to store the page file on
a separate physical disk to improve performance.
330
Optimization
Visual Effects and Paging File Options in Windows 7
Configuring Updates in Windows 7
Before you start
Objectives: Learn how to use Windows Update console to configure updates in Windows 7.
Prerequisites: you have to know what updates are and why are they important.
Key terms: Windows Update, Windows 7, configuration
Windows Update Console
To open Windows Update, we can go to to Start > All programs > Windows Update.
Figure 540 - Windows Update Window
When we install Windows 7, we are asked if we want to configure Windows updates. We can choose to
configure it immediately, to configure it later, or to never configure Windows updates. If we choose not to
configure Windows updates to automatically check for updates, we can always check for updates manually.
Let's look at some of the settings of Windows Update. To do that we can select "Change settings" option from
the menu on the left.
Figure 541 - Windows Update Menu
Here we choose different options about Windows updates.
331
Optimization
Visual Effects and Paging File Options in Windows 7
Figure 542 - Update Options
We have different options for important update installation:
Figure 543 - How to install important updates
So, updates can be installed automatically, they can be downloaded but not installed, and they can be checked
for but not downloaded and installed. We can also choose not to install updates at all. We can also choose on
which day and at what time to install updates. For laptops the option to check for updates but not download
them is great. This way we can save battery.
Note that we also have an option to give us recommend updates the same way as important updates. We can
also enable or disable standard users to install updates on our computer.
Checking for Updates
When our computer checks for updates, the system will contact Microsoft Windows update servers. For
example, in our case, after the check we only have one important update available for installation.
332
Optimization
Visual Effects and Paging File Options in Windows 7
Figure 544 - Available Updates
We can click on "1 important update is available" and see what updates are available for install.
Figure 545 - List of Updates
We can also right-click and hide the update.
Figure 546 - Hide Update Option
If we do that, it won't be installed and won't be brought up for installation in the future. We can also copy its
details. We can also view more information about the selected update on the right-hand side of the window.
333
Optimization
Visual Effects and Paging File Options in Windows 7
Figure 547 - Information about Update
If we hide an update, but we want to bring it back again and install it, we have to go to the "Restore hidden
updates" option in the Windows Update console.
Figure 548 - Hidden Updates Option
In that window we will select the update we want to restore, and then click the Restore button.
Windows vs. Microsoft Updates
By default, we will only get updates for Microsoft Windows operating system. To be able to install updates for
Windows and other Microsoft products, we can click on "Find out more" option.
334
Optimization
Visual Effects and Paging File Options in Windows 7
Figure 549 - Find out more Option
This takes us to a website where we can choose to install a new version of Microsoft Update, which allows us
to download updates for not only Windows but also other products from Microsoft, such as Microsoft Office.
Figure 550 - Microsoft Update
This upgrade can also be done through the Microsoft Office. Once we install Microsoft Office and run it for
the first time, it will ask us if we want to use Microsoft Update to get updates for Microsoft Office as well.
Once we upgraded the Windows Update to a newer version, we get two more option in Update settings.
Figure 551 - New Update Options
335
Optimization
Visual Effects and Paging File Options in Windows 7
Now we can choose to get (or disable) updates for other Microsoft products. We can also choose to get other
Microsoft software such as various add-ons or similar.
After the upgrade, we have checked for updates again, and now we have three updates available for install.
Figure 552 - New Updates Available
Let's try and install them now.
Figure 553 - Installation
As we can see, whenever update is being installed, a restore point is created. This means that in case the update
causes a problem, we can revert back to the point of time before the update was installed.
Note that installing update will often require a reboot.
Figure 554 - Reboot Required
After the reboot, we can go back to Windows Updates and check the Update history on the left hand side.
336
Optimization
Visual Effects and Paging File Options in Windows 7
Figure 555 - Update History
Here we can see all updates that were installed, when it happened, the status of the installation, and the
importance of the update.
Figure 556 - List of Installed Updates
We can also right-click specific update in this list and see the details of the update installation.
Figure 557 - Installation Details
We can gather more information about the update from the knowledgebase article in the update installation
details. This is particularly useful if we have an installation error and we need to fix it.
337
Optimization
Visual Effects and Paging File Options in Windows 7
Uninstalling Updates
All updates that we install can be uninstalled. To do that we can go to the "Installed Updates" option on the
left hand side of the Windows Update window.
Figure 558 - Installed Updates Option
Here we will see a list of updates. We can right-click particular update and then uninstall it.
Figure 559 - Uninstall Option
338
Optimization
Configuring WSUS and Other Update Options in Windows 7
Configuring WSUS and Other Update Options in Windows 7
Before you start
Objectives: Learn how to use Group Policy Editor to configure updates in Windows 7.
Prerequisites: you have to know what updates are and what WSUS is.
Key terms: group policy editor, Windows Update, Windows 7, configuration
WSUS Configuration
By default, each Windows client contacts the Microsoft servers on Internet for updates. We can use local group
policies to connect our Windows 7 to the Windows Server Update Services server and download updates from
it. As we know, WSUS server resides locally within our network and allows us to connect to it from our client
without having to go through the Internet to get updates. So, we will open Group Policy Editor by entering
gpedit.msc in our search bar. In Editor, we will navigate to Computer Configuration > Administrative
Templates > Windows Components > Windows Update.
Figure 560 - Group Policy Editor
As we can see, using Group Policy we can manage almost all of the same settings that we can manage in the
Windows Update console. There are few important policies we need to configure to be able to connect to and
download updates from the local update server. The first one is "Specify intranet Microsoft update service
location". If we open this policy, we can enable it and specify the location of the WSUS server.
339
Optimization
Configuring WSUS and Other Update Options in Windows 7
Figure 561 - Update Server Location
In our case the WSUS server is available at "". The update server and the statistics server are
usually the same server. The next thing we can configure is the "Configure Automatic Updates" policy.
340
Optimization
Configuring WSUS and Other Update Options in Windows 7
Figure 562 - Automatic Updates Options
In our case we have configured automatic download and notify for installation every day at 5 pm. Other
options are:
Notify for download and notify for install
Auto download and schedule the install (with this we configure the schedule of when to apply
updates)
Allow local admin to choose setting
If we disable the "Configure Automatic Updates" policy, the automatic updates are not used. In this case users
can only go to the Windows Update website and then manually download and install updates. If that policy is
enabled, users cannot change the configured settings through the Windows Update console. Some of the other
group policies are:
Enable client-side targeting policy - enables us to allow clients to add themselves automatically to
target computer groups on the WSUS server.
Reschedule Automatic Updates Scheduled Installations policy - enables us to set the installation to
occur between 1 and 60 minutes after the system starts up.
341
Optimization
Configuring WSUS and Other Update Options in Windows 7
No Auto-Restart For Scheduled Automatic Updates and Installations policy - allows Automatic
Updates to disregard a required restart when a user is logged on. The will receive a notification about
the restart but is not required to restart the machine.
Automatic Updates detection frequency policy - specifies the time period for clients to wait before
checking for updates.
Allow Automatic Updates immediate installation policy - specifies whether Automatic Updates should
automatically install certain updates that do not interrupt Windows Services and don't force a restart.
Delay restart of schedule installations policy - specifies how long Automatic Updates waits before
performing a restart. If not configured, the system waits 5 minutes before restarting. This policy only
applies when update installations are scheduled.
Re-prompt for restart with scheduled installations policy - specifies how long Automatic Updates waits
before prompting the user for a scheduled restart. If not configured, the system prompts every 10
minutes.
Allow non-administrators to receive update notifications policy - allows us to deliver update
notifications when a non-administrator user is logged on to the computer.
Do not display 'Install Updates and Shut Down' option in Shut Down Windows dialog box policy when enabled, the install update option will not be displayed. In this case, users will be unable to
choose not to install the updates, and updates will be installed when they try to shut down the
computer.
In our case we will also enable the "Turn on Software Notifications" policy, and also "Turn on recommended
updates via Automatic Updates" policy. If we now open Windows Update console, we will notice that the
interface looks a little different. It now tells us that we receive updates "managed by your system
administrator". That basically means we are contacting a local update server.
Figure 563 - Windows Update Console
Now, we can actually force Windows updates in Windows 7 to contact the Microsoft update server on the
Internet, while the local policy stays the same. We can do that if we click on the "Check online for updates
from Windows Update" option on Windows Update console.
342
Optimization
Configuring WSUS and Other Update Options in Windows 7
Figure 564 - Check Online Option
We can also use elevated command prompt to check for updates. To do that we can enter the command
wuauclt /detectnow
The Windows updates automatic updates command line tool (wuauclt) will contact the local Windows update
server and try to register for updates and then download available updates. WSUS server will scan the client to
check to see what updates it has installed and what updates it needs. At the WSUS server we could see the
status of our Windows 7 client computer, but that's a topic for another article.
343
Optimization
Setting Up Backup in Windows 7
Setting Up Backup in Windows 7
Before you start
Objectives: Learn how to configure and use Backup and Restore tool in Windows 7
Prerequisites: you have to know about backup options in Windows.
Key terms: backup, configuration, Windows 7, system image
Backup and Restore Console
To open Backup and Restore console we can go to Control Panel, choose the "Small icons" view, and then
click on the Backup and Restore option.
Figure 565 - Backup and Restore Console
The first time we use the Backup and Restore tool we can choose the "Set up backup" option. Have in mind
that we cannot have more than one backup job on a system at a time. When we click on the "Set up backup"
link, we will first have to choose the backup location.
Figure 566 - Available Locations
344
Optimization
Setting Up Backup in Windows 7
In our case we will choose E: drive as our destination and click Next. On the next screen we choose if we want
to let Windows to choose what to back, or we can choose ourselves. In our case we will choose the "Let me
choose" option.
Figure 567 - What to back up
On the next screen we choose what to back up. Note that we can choose to include a system image of our
drives. This is also the case when we let Windows decide what to backup.
Figure 568 - Backup Items
When we include a system image of drives, our entire system is backed up to a VHD file, so we can use it for
recovery. If our system stops working, and we have a system image of it, we can easily restore it back to the
point where we made the system image backup. Note that we can choose to backup users’ libraries and we can
choose to backup specific files and folders. In our case we have selected Kim Verson's and Students libraries,
and we have selected C:\Docs folder.
345
Optimization
Setting Up Backup in Windows 7
Figure 569 - Selected Items
On the next we can see a summary of what we are backing up.
Figure 570 - Review
Note that we can also change the schedule of the backup. By default, once we create one backup, it will
automatically backup every Sunday at 7 PM. If we click on the Change Schedule, we will see this screen.
346
Optimization
Setting Up Backup in Windows 7
Figure 571 - Schedule Options
Note that we can also disable the schedule. We can also choose to run the backup daily, weekly, or monthly.
We will leave default options here.
We are also being warned that we might need a system repair disc if we want to restore a system image file. We
can boot from the Windows PE utility CD or we can boot from the Windows 7 media as well. We can now
click on the "Save settings and run backup" option.
Figure 572 - Backup in Progress
During the backup, first shadow copies are created for our files. That way, in case we have any open files, they
can be backed up as well.
Note that on the Backup and Restore console, we have an option to create a system image directly.
347
Optimization
Setting Up Backup in Windows 7
Figure 573 - System Image Option
This way we don't have to create a full backup together with the system image. We can only create a system
image. We can choose to save the image to a hard disk, have it burned directly to a CD or DVD, and save it to
a network location.
Note that we also have an option to create a system repair disc. For that we need to have a blank burnable
media like a CD or DVD. We actually don't have to create a system repair disk if we have a Windows PE or
Windows 7 bootable DVD.
Once the backup is complete, we can click on the "Manage space" option, which will show us how much space
our backups are taking up.
Figure 574 - Manage Space
We can also view our backups to see all the previous backups we've made by clicking on the "View backups"
button.
348
Optimization
Setting Up Backup in Windows 7
Figure 575 - View Backups
We can even select the backup and delete it from here. For system images we can select how Windows retains
older system images by clicking on the "Change settings" button.
Figure 576 - Older System Images
We can let Windows to manage space or we can choose to keep only the latest system image, to minimize
space usage.
We can always change settings for our backup by clicking the "Change settings" option. Keep in mind that we
can only have one backup configuration. We can't have multiple different scheduled backups.
Exploring Backup
If we open our backup location, we will see two items.
349
Optimization
Setting Up Backup in Windows 7
Figure 577 - Exploring Backup
The first item is a backup file, and the second is a WindowsImageBackup folder. We can actually open that
WindowsImageBackup folder. In it we will see the folder for our specific machine. In that folder we will see
this.
Figure 578 - Image Backup Folder
The first item is a Backup Set folder (Backup 2015-04-29 073131). Within the backup set folder we will see two
VHD files.
350
Optimization
Setting Up Backup in Windows 7
Figure 579 - Backup Set Folder
One VHD file is smaller and contains system and BitLocker settings. The second VHD file is larger and
contains the actual system image. We can actually mount that VHD file. To do that we can go to Disk
Management, and select the "Attach VHD" option.
Figure 580 - Attach VHD Option
We specify the location of the VHD file and click OK.
351
Optimization
Setting Up Backup in Windows 7
Figure 581 - Image Location
The VHD file will get a drive letter and the auto play will start up. In our case it got the letter F:, and if we
open it, we see that it has the same content as our C: drive.
Figure 582 - F: Drive
We can actually now copy files to our F: drive, and those files will remain there as well. Let's now take a look at
our WIN-7-VM1 backup file. Windows 7 saves everything in a sort of compressed file. If we right-click it, we
will see the Restore option.
352
Optimization
Setting Up Backup in Windows 7
Figure 583 - Restore Options
We can also select the Open option. This will actually show the contents of the backup file.
Figure 584 - Backup File Contents
We can browse inside the backup and go to backup files, open up the files one by one. So, this is actually a filebased backup, which makes restoring much easier. We can simply search for the file we want, and then restore
it.
353
Optimization
Restoring Data from Backup in Windows 7
Restoring restore and recover files in Windows 7, we can go to Control Panel > All Items > Backup and Restore
option. In our case we already have a backup completed.
Figure 585 - Restore Option
To restore files from existing backup, we can click on the "Restore my files" button.
354
Optimization
Restoring Data from Backup in Windows 7
Figure 586 - Browse or Search for Files
By default, all files will be restored to their latest version. However, we can click on the "Choose a different
date" option to select another date and time.
Figure 587 - Select Date and Time
In our case we will leave the default option to restore latest version. So, when we click on the Search button,
we can search for a file to restore. For example, in our case we have entered "*.pdf" which will show us all files
with the .txt extension.
Figure 588 - Searching For Files
We will select that file and click OK. This will add that file to the list of files to be restored.
355
Optimization
Restoring Data from Backup in Windows 7
Figure 589 - List of Files to Be Restored
We can also choose specific files by clicking on the "Browse for files" option. Note that this takes us directly to
the Windows backup folder which we can browse.
Figure 590 - Browse Backup
So, from here we can browse all files and then select particular files that we want to restore. If we click on the
"Browse for folders" button, which will allow us to select particular folder to restore. When we have selected all
files and folders that we want to restore, we can click on the Next button. On the next screen we will be able to
choose where to restore our files.
356
Optimization
Restoring Data from Backup in Windows 7
Figure 591 - Restore Location
We have selected to restore files to new location and selected the option to restore files to their original
subfolders. This means that actual folder tree and structures will be saved, instead of all the files thrown into
one single location. If we select the first option ("In the original location"), this will overwrite the existing files
if they exist. We can now click the Restore button, and take a look at our files.
In addition to doing restorations directly, we can choose to restore from another backup file. To do that, we
click on the "Select another backup to restore files from", on the Backup and Restore console. If we made a
backup to a removable device or to a network location, we would be able to select and restore from that
backup here.
Figure 592 - Another Backup Location
Restore Points and Shadow Copies
We can use restore points and previous versions to protect our files and the operating system. We can
configure system restore settings by selecting "System protection" under Control Panel > All Items > System
(in System properties). We can also go there by right-clicking Computer icon and selecting Properties option.
357
Optimization
Restoring Data from Backup in Windows 7
Figure 593 - System Protection Tab
By default the C: drive has system protection enabled. All other drives will have system protection disabled by
default. We can configure each partition with a different system protection setting. Let’s select the C: drive and
click on the Configure button.
358
Optimization
Restoring Data from Backup in Windows 7
Figure 594 - Drive C: Options
So, we can choose restore system settings and previous versions of files being saved, or we can choose to only
save previous versions of files, or we can turn off system protection completely. We can also configure the
amount of disk space that will be dedicated to system restore points. The more disk space we have dedicated,
the more restore points we will be able to save. We can also delete all previous restore points, including system
settings and previous version files by clicking the Delete button.
On partitions that we primarily only have data, and have no system settings, we can safely choose only previous
versions of files, when we enable system protection on that kind of drive.
If we go to System Protection tab again, we can see that we can manually create a restore point by clicking on
the Create button. When we do that, we will be asked for restore point description.
359
Optimization
Restoring Data from Backup in Windows 7
Figure 595 - Restore Point Description
In addition to saving system settings that can allow us to restore our configurations in case our computer
becomes corrupted, system protection also saves previous versions of files. System protection can create
multiple previous versions of files, as long as they're available and we have enough space to keep multiple
previous versions of files. In that way, if we accidently make an undesired change to a file or if we delete it, we
can get the previous version of the file back from previous version feature. To get the previous version of the
file, we can right-click particular file, open its properties, and then go to the Previous Versions tab.
Figure 596 - File Versions
We can also right-click a particular folder, open its properties and then go to the Previous Versions tab. This
way we will be able to choose all changes for the whole folder.
360
Optimization
Restoring Data from Backup in Windows 7
Figure 597 - Folder Versions
So, we can select a particular version of file or folder (depending on what we selected) and then either open it,
copy it, or restore it, by clicking on the appropriate button.
Keep in mind that by default, previous versions are created every time a restore point is created. Now, as we
know, restore point is automatically generated when a system event such as update installation, driver
installations and other important events happen. It is also generated automatically at specific time of day, every
day. We can check when the restore point is going to be created in Control Panel > Administrative Tools >
Task Scheduler. In Task Scheduler we can navigate to Task Scheduler Library > Microsoft > Windows >
System Restore. Here we will see one task called "SR". If we select it and open the Triggers tab, we will see that
a system restore point is automatically created every day at 12 AM, and every time when the computer turns on.
361
Optimization
Restoring Data from Backup in Windows 7
Figure 598 - System Restore Task
We can even go ahead and add more triggers. When we have this enabled, we can have an ongoing previous
versions of our files and our system information.
362
http//
Utilize Windows 7 | https://www.scribd.com/document/264219730/Utilize-Windows-7 | CC-MAIN-2019-04 | refinedweb | 54,141 | 61.46 |
Introduction
Eclipse is an ideal platform for developing Web applications using Java™ technologies. The 3-tier design for building dynamic Web applications is well suited for use with JSPs and Servlets running in a servlet container like Apache Tomcat. The persistent data layer is aptly provided by the Derby database. The Eclipse Web Tools Platform (WTP) project set of tools for developing J2EE™ and Web applications, along with the Derby Eclipse plug-ins, allows for rapid and simplified Web development.
This article discusses some of the functionality provided by the WTP, the Derby database plug-ins, and a complete sample application that uses JSPs, JavaServer Pages Standard Tag Library (JSTL), and Servlets. The sample application is a fictitious and simplified airline flight reservation system.
In order to get the most out of this article, you should understand the basics of JSP, JSTL, and Servlet technology, understand simple SQL, and have some knowledge of Eclipse. Some of the features of the WTP are used in this article, but it is not a comprehensive tutorial of the WTP tools. To learn more on these topics please refer to the list of resources at the end of this article. If you already know some of the background of the WTP and want to get started downloading all of the required software, skip to the section Software requirements. Otherwise, read the next section to learn what the WTP is and how some of these components are used from within Eclipse to develop the sample application.
IBM Cloudscape™ is the commercial release of the Apache Derby open source database. The names are used interchangeably in this article for general terms, unless reference to a specific file or name is used.
Eclipse WTP project
The Eclipse Web Tools Platform (WTP) project allows Eclipse users to develop J2EE Web applications. Included in this platform are multiple editors, graphical editors, natures, builders, a Web Service wizard, database access and query tools, and other components. The project provides a large number of tools. Only a limited number of these tools will be demonstrated in relation to building a Web application using Derby as the back-end database.
The WTP's charter, as defined at, is: "... to build useful tools and a generic, extensible, standards-based tool platform upon which software providers can create specialized, differentiated offerings for producing Web-enabled applications." This article will not discuss building new tools for this platform, but instead as an open platform to build Web applications using Open Source components.
Web standard tools and J2EE standard tools
The WTP is divided into two sub-projects, the Web Standard Tools and the J2EE Standard Tools. The Web Standard Tools (WST) project provides common infrastructure that targets multi-tier Web applications. It provides a server view that allows you to publish resources created from within Eclipse and run them on a server. The WST does not include specific tools for the Java language, or for Web-framework-specific technology.
The J2EE Standard Tools (JST) project provides tools that simplify development for the J2EE APIs, including EJB, Servlet, JSP, JDBC™, Web Services, and many more. The J2EE Standard Tools Project builds on the support for the Server Tools provided by the Web Standard Tools Project, including servlet and EJB containers.
The next section discusses all the software components you need in order to build and run the sample application.
Components of the Web application
The sample application uses the following software components and technologies:
- Eclipse
- Use the IDE to write and run the sample application. It is the foundation for developing and building Java applications.
- Use the Java Development Tools (JDT) included with Eclipse to compile the Java classes that are part of the application.
- WTP
- Use the editor to create the JSP files. The editor includes content assist for JSP syntax.
- Use the Servers view to start and stop the external Tomcat servlet engine.
- Use the J2EE perspective view to create the Dynamic Web application that assembles and configures the J2EE Web application, including the standard structure and deployment descriptor common to all J2EE Web applications.
- Create a connection to a Derby database through the Database Explorer view.
- Derby plug-ins
- Add the Derby nature to the Dynamic Web project to include the JAR files in the project.
- Start and stop the Derby network server during application development.
- Test and run SQL queries using the ij SQL query tool.
- Set the project's derby.system.home property to point to the database.
- JavaServer Pages Standard Tag Library (JSTL)
- This tag library enables JSP-based applications to use a standard tag library to perform common tasks. The sample application uses these tags to perform tasks like iteration and database access. Expression Language (EL), a scripting language, is also used in the JSPs.
- Apache Tomcat servlet engine
- Runs the Web application consisting of the JSPs and Servlets.
- Provides support for the Servlet 2.4 and JSP 2.0 APIs, including support for EL.
- Provides support for defining the Derby database as a Data Source in the deployment descriptor of the Web application.
Software requirements
The software described in this section is available for download at no cost and must be installed prior to running the examples and building the sample Web application.
Either of the following Java development kits (Tomcat 5.5 requires at least 1.5):
- IBM SDK version 1.5.x or higher.
- Sun JDK version 1.5.x or higher.
Eclipse and WTP. You can download one zip that contains the Eclipse SDK, all of the WTP prerequisites, and WTP itself. On Windows®, this file is called wtp-all-in-one-sdk-1.0-win32.zip. If you prefer to download the Linux® distribution, grab the file wtp-all-in-one-sdk-1.0-linux-gtk.tar.gz. You can download either of these files from eclipse.org (see Resources).
In case you already have Eclipse installed, or some of the prerequisites for WTP, the versions of the plug-ins contained in the wtp-all-in-one zip file are listed below for you to compare. Also, the Download page lists these prerequisites for 1.0 WTP, so you need to make sure your components are at least as current as those listed here. If the versions available for download are different from those listed below, get the version recommended at the WTP site.
- Eclipse 3.1.1, for Windows: eclipse-SDK-3.1.1-win32.zip
- EMF SDK: emf-sdo-xsd-SDK-2.1.1.zip
- GEF SDK: GEF-SDK-3.1.1.zip
- Java EMF Model Runtime: JEM-SDK-1.1.0.1.zip
- Web Tools Platform: wtp-1.0.zip
Derby database Eclipse plug-ins (available from apache.org as zip files -- see Resources). The Apache Derby database recently released version 10.1 of the database engine. The following versions of the plug-ins are required to run on Eclipse 3.1:
- Derby Core plug-in, Version 10.1.1 or higher (10.1.2 is recommended)
- Derby UI plug-in, Version 1.1.0
Apache Tomcat. Download Version 5.5.15 (see Resources).
JavaServer Pages Standard Tag Library (JSTL). Download the Standard 1.1 Taglib, jakarta-taglibs-standard-1.1.2.zip, from the Apache Jakarta Project (see Resources).
The sample application source code and WAR file:
- A WAR file is a Web Application Archive and is the standard unit for packaging and deploying J2EE Web applications. All J2EE-compliant servlet containers accept WAR files and can deploy them. Download the LowFareAir.war file to your file system (see Downloads).
- Download the zip file LowFareAirData.zip, which contains the Derby database and sample SQL files to access the airlinesDB database. (See Downloads.)
Software configuration
After downloading all required components, you need to configure them so you can start building the application.
Install a JDK
If you do not have a Version 1.5.x or higher JDK, install it. A JDK is required, not just a JRE.
Install Eclipse and the WTP
Install Eclipse by unzipping the wtp-all-in-one-sdk-1.0-win32.zip into a directory where you want Eclipse to reside. If Eclipse is already installed and you downloaded the individual components listed above, unzip those in the Eclipse home directory, since they are all plug-ins and they will install to the plugins directory of Eclipse.
Install and configure Jakarta Tomcat
Unzip or install Jakarta Tomcat to a different directory than your Eclipse installation directory.
Now you need to configure Eclipse to run Tomcat as a server from within Eclipse using the WTP. To do this:
- Go to and select the tutorials link under the WTP Community section.
- From the Tutorials page, select the tutorial called "Building a School Schedule Web Application."
- Follow all the instructions in the section called "Installing the Tomcat Runtime in Eclipse" for this tutorial. However, select a Tomcat 5.5.15 installation instead of the 5.0.28 install like the instructions say. For the purposes of this sample Web application, you do not need to complete the whole tutorial.
Install the Derby plug-ins
Unzip both of the files (the Derby Core and UI plug-in zip files) to the plugins directory, from the Eclipse home directory. The Derby plug-ins come with a complete tutorial and examples of how to use all of their functionality. To access the help, select Help > Help Contents > Derby Plug-ins User Guide.
Application design
The LowFareAir Web application follows the standard 3-tier design model consisting of a presentation layer, business logic and control layer, and a data or persistence layer. The JSPs, including the JSTL tag libraries, provide the UI or presentation layer. The Servlets and supporting Java classes provide the business logic and control the flow of the application. The Derby database and JavaBeans provide the data layer. The diagram below illustrates this.
Figure 1. Sample application design
A note about accessing the data layer from the presentation layer
The presentation layer, represented by the JSPs, should generally not interact directly with the data layer and hence should not be making database queries. The design of this application follows the accepted paradigm, with the exception of the first JSP. For quick prototyping efforts it is acceptable to combine the database access in the view layer, compromising the strict separation of data from view. The first JSP, Welcome.jsp, occupies both the presentation layer and the data layer by using the JSTL SQL library to issue an SQL query from the page.
The other JSPs act as the presentation layer only, and pass all data handling responsibility to the Servlets, which interact with the Derby database. The JSTL SQL library example is shown here, in case you are interested in using this methodology for future prototyping of Web applications, but it is not recommended for production environments.
LowFare Air sample application
The sample application allows new users the chance to register for or existing users to log into the application. Once the user is logged in, numerous flights are presented for booking. Only direct flights are offered, so the flight chosen is checked to see if the origin and destination direct flight is available. If the flight is available the user can choose to book the flight. Finally, the user can see a history of all flights booked through LowFare Air.
The flow of the sample application consists of these steps:
- User registration or verification
- The JSPs used in this part of the application are Welcome.jsp, Login.jsp, and Register.jsp
- LoginServlet acts as the controller -- the user's name is either verified in the APP.USERS table in the Derby database, or inserted into the table.
- A persistent cookie is set once a successful registration occurs, and the client's user ID is added to the session once a successful login occurs.
- Flight retrieval and selection
- Welcome.jsp is used to select the flight, and GetFlights.jsp is used to retrieve the flight.
- CheckFlightsServlet acts as the controller. If there are flights between the two selected cities, the flight information is passed to GetFlights.jsp. If not, the user is returned to Welcome.jsp to select another flight.
- If there are flights, the DerbyDatabase class places the flight information retrieved from the database into a JavaBean called FlightsBean.
- Book the user's flight by updating the Flight History
- The JSPs used are BookFlights.jsp and GoodBye.jsp. BookFlights.jsp asks the user for final confirmation on the flight they want to book. GoodBye.jsp displays all flights booked for the user with Derby Airlines.
- UpdateHistoryServlet updates the APP.FlightHistory table with the users name and flight they just booked. The request is then forwarded to GoodBye.jsp.
- Log out user
- The final phase of the application is to either log out or to book another flight. The JSPs used are LoggedOut.jsp or, if the user wishes to book another flight, Welcome.jsp.
- If the user chooses to log out the user ID is removed from the Session object. Therefore the next time the user returns to the site a persistent cookie remains, but the user ID is no longer in the Session object, and therefore the user must log in again.
The figure below shows this same flow pictorially.
Figure 2. Sample application flow
Creating the Web project from the WAR
To understand how to use the various tools included with the WTP and the Derby plug-ins, import the application as a WAR file, the standard packaging unit for Web applications, which is in a JAR file format.
The first step towards building any Web application that uses JSPs or Servlets is to create a Dynamic Web Application. You can create one using the WTP set of tools, and it will automatically create the correct directory structure for J2EE Web applications. Import the WAR file into the Dynamic Web Project folder of the Project Explorer view to create a new Web project.
Launch Eclipse, if it is not already running, and import the WAR file to create a new Dynamic Web Project by following these steps:
- Open the J2EE Perspective.
- From the Project Explorer view, right-click the Dynamic Web Projects folder.
- Select Import, then in the Import window, select WAR file and click Next.
- In the WAR Import window, browse to the LowFareAir.war file you downloaded earlier (see Software Requirements above). Name the project
LowFareAir, and make sure the Target server is Apache Tomcat V5.5 (which you configured earlier -- see Software configuration above). Click Finish.
Figure 3 shows the last step in the process.
Figure 3. Importing a WAR file to create the Dynamic Web Project
You also need to import three JAR files that are not included in the WAR file: jstl.jar and standard.jar from the Jakarta taglibs package you downloaded earlier, and the derbyclient.jar file from the Derby core plug-in. Normally a complete WAR file would contain these JAR files, but for demonstration purposes you should know how to import them into the Dynamic Web Project.
To retrieve the JAR files from the Jakarta package, unzip the jakarta-taglibs-standard-1.1.2.zip file. The jstl.jar and standard.jar files are located in the newly created jakarta-taglibs-standard-1.1.2/lib directory. To import them:
- Open the Dynamic Web Projects folder. The LowFareAir project you just imported will appear. Expand this folder, and then the WebContent folder.
- Right-click the WebContent/WEB-INF/lib folder and select Import. In the Import window, select File System, and then click Next.
- Browse to the subdirectory jakarta-taglibs-standard-1.1.2/lib, where you unzipped the taglibs, and select jstl.jar and standard.jar. Make sure you are importing into the LowFareAir/WebContent/WEB-INF/lib directory. Then click Finish.
Now you need to add the derbyclient.jar file to the libraries available to the Web application. Your Web application will use the JDBC driver in derbyclient.jar to make connections to the database.
To import derbyclient.jar:
- Right-click the WebContent/WEB-INF/lib folder and select Import. In the Import window, select File System, then click Next.
- Browse to the plugins directory under the Eclipse home directory, and then to the directory org.apache.derby.core_10.1.2. Select derbyclient.jar. Make sure you are importing into the LowFareAir/WebContent/WEB-INF/lib directory. Then click Finish.
This completes importing the Web components, including the Java source files and all libraries for the application. Next, import the Derby database
airlinesDB, complete with sample data.
Configuring the data layer
To configure the data layer and the tools that access the database for your application:
- Add the Apache Derby Nature to the LowFareAir project.
- Import the LowFareAirData.zip file into the project. The zip file contains the
airlinesDBDerby database, which contains all of the data for the application as well as some sample SQL scripts.
- Configure the Web application deployment descriptor, web.xml, to contain a data source pointing to the
airlinesDBdatabase.
- Set the Derby property
derby.system.hometo point to the full path of the
airlinesDBdatabase. By setting this property, all references to the
airlinesDBdatabase in the JDBC connection URLs can just refer to 'airlinesDB' instead of the full file system path.
Adding the Apache Derby nature
The Web application uses a Derby database to store and query flight information for the fictional LowFareAir airlines. An easy way to access and use Derby databases in Eclipse is via the Derby plug-ins.
The Derby plug-ins allow you to add the Derby nature to any Eclipse project. Adding a nature to a project, including a Dynamic Web Project, means that project "inherits" certain functionality and behaviour. Adding the Derby nature adds the Derby database JAR files and the command line tools bundled with Derby to the Eclipse environment.
The Project Explorer view will now show the LowFareAir project you just created.
To add the Derby nature to the LowFareAir project, right-click it and select the menu item Apache Derby > Add Apache Derby nature.
Import LowFareAirData.zip
Included in the source code is
airlinesDB, the sample database used for the Web application. This database, along with some sample SQL, needs to be imported into the LowFareAir project. To do this:
- Expand the Dynamic Web Projects folder. Right-click the LowFareAir folder and select Import. In the Import window, select Archive file, then click Next.
- Browse to LowFareAirData.zip, and make sure that in the left frame, the / directory is checked. This includes the data and sql folders. For the name of the Into folder select LowFareAir, then click Finish.
- If the import was successful, the LowFareAir folder should contain two new subfolders: data and sql. The data folder will contain the airlinesDB directory (database).
- The sql directory contains three SQL files called airlinesDB.sql, flights.sql, and flighthistory_users.sql.
Now all of the files required for the Web application have been imported, and the LowFareAir project should look similar in structure to Figure 4.
Figure 4. Project Explorer view of LowFareAir project
Configure web.xml with the Derby data source
The web.xml file contains a data source entry to use the Derby airlinesDB database as a data source. This is not a requirement for any Web application to connect to a Derby database; however, the application uses a data source for the first JSP page for demonstration purposes. The other JSPs do not use the data source, and the Servlets use a standard Java class that use JDBC to connect to the database.
To determine the location of the airlinesDB on the file system, right-click the airlinesDB folder under the data directory of the LowFareAir project and select Properties. The Properties window shows a Location field which has the full file system path to the airlinesDB directory. Copy this string so it can be used in the next step. For instance, this path might be something like: C:\eclipse\workspace\LowFareAir\data\airlinesDB
Open web.xml (under the WebContent/WEB-INF directory) and browse to this section of it while viewing in Source mode (the entry in the param-value section has been modified with a line break for readability, but the URL should be a continuous line):
Listing 1. Web.xml context-param section
<context-param> <param-name>javax.servlet.jsp.jstl.sql.dataSource</param-name> <param-value> jdbc:derby://localhost:1527/C:/eclipse/workspace/LowFareAir/data/ / airlinesDB;user=a;password=b;, org.apache.derby.jdbc.ClientDriver </param-value> </context-param>
Change the value in the <param-value> section to the database URL for your environment, using the full path to the
airlinesDB database you just copied and save the file. Without editing this correctly, the first page of the application (Welcome.jsp) will fail. Also, you need to start the network server before running Welcome.jsp, since the URL shown above attempts to access the Network Server using the Derby Client driver. Note: Either forward or backward slashes can be used for the database connection URL in a Windows environment.
Set derby.system.home for the project
The next step to configuring the Derby database environment from within Eclipse is to edit the Derby system property called
derby.system.home to point to the location of the
airlinesDB database. This allows you to connect to
airlinesDB using the Derby plug-ins without specifying the full file system path to the database. Only the name
airlinesDB needs to be listed in the database connection URL.
Use the path to the airlinesDB directory you copied earlier, just slightly modified, to set
derby.system.home.
- Right-click the LowFareAir project and select Properties.
- In the left side of the Properties window for the LowFareAir project, select Apache Derby.
- On the right side are the Apache Derby properties that you can change. The Derby System Property called
derby.system.homeis currently set to the default value (.). Change it to point to the full path of the directory where the airlinesDB directory resides. Note: You can also modify the port that the network server listens on, in the
portproperty.
Edit the value for the
derby.system.homeproperty to the full path of your data directory. Paste in the string you copied above, and remove the trailing \airlinesDB. So given the example path from earlier, the derby.system.home property would be: C:\eclipse\workspace\LowFareAir\data. Note: Do not enter the name of the database directory itself -- it should be the directory where the database directory resides, in this case data, not the airlinesDB directory itself.
- Finally click OK to save the setting for the project.
Next you'll start the Derby Network Server, make a connection to the airlinesDB database and issue some SQL using the ij tool provided with the Derby plug-ins.
Starting the Derby network server and running ij
Since you are about to run some queries against the tables in the airlinesDB, it's useful to know which tables you have and how they are defined. These are shown below. The SQL file, airlinesDB.sql, was used to create the database. Do not run airlinesDB.sql again unless you delete the old database and want to recreate all of the tables in a new database.
Listing 2. Create table statements for the airlinesDB database
CREATE TABLE APP.CITIES ( CITY_ID INTEGER NOT NULL constraint cities_pk primary key, CITY_NAME VARCHAR(24) NOT NULL, COUNTRY VARCHAR(26) NOT NULL, AIRPORT VARCHAR(26), LANGUAGE VARCHAR(16), COUNTRY_ISO_CODE CHAR(2) ); CREATE TABLE APP.FLIGHTS ( FLIGHT_ID CHAR(6) NOT NULL, SEGMENT_NUMBER INTEGER NOT NULL, ORIG_AIRPORT CHAR(3), DEPART_TIME TIME, DEST_AIRPORT CHAR(3), ARRIVE_TIME TIME, MEAL CHAR(1) CONSTRAINT MEAL_CONSTRAINT CHECK (meal IN ('B', 'L', 'D', 'S')), FLYING_TIME DOUBLE PRECISION, MILES INTEGER, AIRCRAFT VARCHAR(6), CONSTRAINT FLIGHTS_PK Primary Key (FLIGHT_ID, SEGMENT_NUMBER) ); CREATE TABLE APP.FLIGHTAVAILABILITY ( FLIGHT_ID CHAR(6) NOT NULL , SEGMENT_NUMBER INTEGER NOT NULL , FLIGHT_DATE DATE NOT NULL , ECONOMY_SEATS_TAKEN INTEGER DEFAULT 0, BUSINESS_SEATS_TAKEN INTEGER DEFAULT 0, FIRSTCLASS_SEATS_TAKEN INTEGER DEFAULT 0, CONSTRAINT FLIGHTAVAIL_PK Primary Key (FLIGHT_ID, SEGMENT_NUMBER, FLIGHT_DATE), CONSTRAINT FLIGHTS_FK2 Foreign Key (FLIGHT_ID, SEGMENT_NUMBER) REFERENCES FLIGHTS (FLIGHT_ID, SEGMENT_NUMBER) ); CREATE TABLE APP.FLIGHTHISTORY ( ID INTEGER NOT NULL GENERATED ALWAYS AS IDENTITY, USERNAME VARCHAR(26) NOT NULL, FLIGHT_ID CHAR(6) NOT NULL, ORIG_AIRPORT CHAR(3) NOT NULL, DEST_AIRPORT CHAR(3) NOT NULL, BEGIN_DATE CHAR(12), CLASS CHAR(12) ); CREATE TABLE APP.USERS ( ID INTEGER NOT NULL GENERATED ALWAYS AS IDENTITY, USERNAME VARCHAR(40) NOT NULL, PASSWORD VARCHAR(20) );
Now start the Derby network server by right-clicking the LowFareAir project and choosing Apache Derby > Start Derby Network Server. The console view should state the server is ready to accept connections on the port specified in the Derby properties Network Server settings. Open the sql folder and right-click the flights.sql file. Select Apache Derby > Run SQL Script using 'ij'.
The console window will show the output of the three SQL statements contained in the flights.sql file. If a connection was not made, check to make sure the network server has been started, and that
derby.system.home has been set to the full path to the data directory under the LowFareAir folder.
The WTP data tools -- An alternative
The WTP has a rich set of database tools that allow users to connect to, browse, and issue SQL against Derby, DB2®, Informix®, MySql, Oracle, SQL Server, and Sybase databases. In this section you'll connect to the Derby Network Server using the Derby Network Client driver, and learn how to use some of these tools as an alternative to using the Derby plug-ins.
In the J2EE perspective, select Window > Show View > Other. In the Show View window, select Data > Database Explorer and then click OK. The Database Explorer view will appear in the bottom right part of the workspace. Right-click somewhere in this view, and select New Connection.
The wizard that appears is the New Connection wizard. Uncheck the Use default naming convention checkbox, and name the connection Derby10.1. Under the Select a database manager section, expand the Derby item in the tree and select the 10.1 version of the database system.
In release V10.1 of Derby, a new open source client driver -- derbyclient.jar -- is the recommended way to connect to the network server.
The image below shows the values for each field in my environment. The table following also lists the sample settings.
Figure 5. The New Connection wizard of the WTP Database Explorer
Configuring authentication for Derby databases is available; however, this has not been set up for the airlinesDB database. Use any (non-null) value for user ID and password, and click the Test Connection button. If the network server is running on port 1527, the test should be successful. If it is not, make sure the network server is running on the port specified in the connection URL, and check to make sure all of the values are appropriate for your environment.
Since the network server is used to connect to the
airlinesDB database, multiple JVMs can access it. This means ij, the Database Explorer, and a client application external to Eclipse could all connect to and query the tables in the database.
Once the test connection is successful, click the Next button.
In the Specify Filter window, uncheck the Disable filter checkbox, select Selection and check the APP schema. Then click Finish.
Figure 6. Specifying the filter for the Derby 10.1 connection
Now the Database Explorer view shows the connection to the
airlinesDB database. Expand the tree and browse to the FLIGHTS table under the Tables folder for the APP schema. Right-click the FLIGHTS table, and select Data > Sample Contents.
Figure 7. Sample contents in the Database Explorer
The Data Output view will now appear with the rows in the FLIGHTS table.
Figure 8. The Data Output view
Another feature of the Database Explorer view is the ability to insert, delete, and update rows in tables. The Table Editor provides the ability to modify data in a table. If you want to add another row to the FLIGHTS table, right-click it in the Database Explorer view, and select Data > Edit. Enter a new row, putting values in each column as shown below. Notice on the FLIGHTS tab the asterisk that precedes the word FLIGHTS. This indicates the editor has been changed since the last time it was saved.
Figure 9. The Table Editor
To insert the row into the table, save the editor by selecting File > Save or using the shortcut, Ctrl + S. The Data Output view's Messages tab shows the data was inserted successfully.
Figure 10. Successfully inserting a row into the FLIGHTS table
Other features of the Database Explorer view include the ability to Extract and Load tables, open an SQL Editor to issue ad-hoc SQL, and a Generate DDL option that is very useful to generate SQL scripts that you can use to create entire database schemas or a subset of the schema. You can explore all of these options on your own by right-clicking on the schema object (a table, view, index, or schema) to see which options are available for that particular object.
Exploring the View Layer and JSPs
Now you can start looking at the JSPs in the application. Referring to the flow of the application in Figure 2, the first JSP page is Welcome.jsp. From the Project Explorer, open up the Welcome.jsp file under the WebContent folder. The code for this page is shown in sections below. Note: Some code listings may have a backslash character, "\", to indicate the line of code is continuous but has been formatted for readability.
Listing 3. Importing the Core and SQL taglibs in Welcome.jsp
<%@taglib uri="" prefix="c"%> <%@taglib uri="" prefix="sql"%>
The first two lines include the taglib directives available to the JSP page, so that you can use the core and SQL JSTL tag libraries.
The next section makes use of the core tag library to test if any cookies are set in the user's browser. If there are none, the JSP page is forwarded to Register.jsp. If there is at least one cookie, then a check is made to see if the cookie with the name of derbyCookie is set. If the derbyCookie exists then the next test is to check if the Session object contains a user ID. If not, the user is forwarded to Login.jsp to log in to the application.
If the user does have a user ID in the Session object, the user is allowed to proceed and processing continues on the Welcome.jsp page.
Listing 4. Testing if cookies are set in Welcome.jsp
<HTML> <HEAD> <TITLE>Derby Airlines</TITLE> </HEAD> <BODY> <c:choose> <c:when <jsp:forward </c:when> <c:otherwise> <!-- if the derbyCookie has been set but the username is not in \ the session object --> <c:forEach <c:if <c:if <jsp:forward </c:if> </c:if> </c:forEach> </c:otherwise> </c:choose>
The code below checks to see if the parameter called
nodirectflights is set to true when this page is posted. If you look at the code further down, the action for the form is to post to the CheckFlightsServlet. If the CheckFlightsServlet does not have any direct flights based on the origin and destination the user selects, the parameter
nodirectflights is set to true, the user is returned to this page, and this snippet of code will display the message about no direct flights being available.
Listing 5. Displaying a message if direct flights are unavailable in Welcome.jsp
<c:if <p> There were no direct flights between <font color="blue" size="5"> ${cityNameFrom}</font> and <font color="blue" size="5"> ${cityNameTo}</font>. <br> Please select another flight. </p> </c:if>
You can use the JSTL core
out tag to display the parameters passed to JSPs in either the session or request objects. After a successful login, the user ID is placed in the Session object, and displayed on the Welcome.jsp page when the user accesses this page. Also, notice the use of the
jsp:include tag to include the CalendarServlet which displays the current month, day, and year, as well as a drop down box to select the departure date.
Listing 6. After a successful login
<H3> Welcome to Derby Air, <c:out!</H3> <p> Please proceed to select a flight. </p> <form action="CheckFlightsServlet" method="post"> <table width="50%"> <tr> <td valign="top"> <b>Departure Date:</b><br> <jsp:include <jsp:param </jsp:include> </td>
Here is the section that makes use of the JSTL SQL library. Before using the
sql:query tag the way it is shown below, you have already set up the DataSource in the web.xml file for the application. That entry will be discussed later. For now, notice how easy this tag is to use. The query is issued against the
CITIES table to return the values contained in the
city_name,
country, and
airport columns of the
APP.CITIES table. The results of the query are put in a variable called
cities, which is a
javax.servlet.jsp.jstl.sql.Result object. The Result object has a method called
getRows() that returns all rows contained in it. The rows are returned as an array of
java.util.SortedMap objects.
Listing 7. Using the SQL taglib
<sql:query SELECT CITY_NAME, COUNTRY, AIRPORT FROM APP.CITIES ORDER BY \ CITY_NAME, COUNTRY </sql:query>
Iteration over the rows contained in the
cities Result object is shown below using the core
forEach tag. For each iteration through the array, the variable named
city contains a SortedMap object. The Expression Language allows you to access the value of each column in each row by referring to the column name in the specific SortedMap object representing that row in the database.
Listing 8. Outputting the result of the SQL query
<td> <b>Origin:</b><br> <select name="from" size="4"> <c:forEach <option value="${city.airport}"> ${city.city_name}, ${city.country}\ </option> </c:forEach> </select> <br><br> </td> </tr>
The rest of the page is not shown here. It outputs the Destination drop down box the same way the Origin destination is generated above, and then provides a button for the user to submit the query to check for the flights between the Origin and Destination.
Examining the flow of control and running the application
Before you can run LowFare Air, you need to start the Derby Network Server, if it is not already running. Right-click the LowFareAir folder, and select Apache Derby > Start Derby Network Server.
Now right-click the Welcome.jsp file in the Project Explorer view. Select Run As > Run On Server.
Figure 11. Running Welcome.jsp on the Tomcat server
This brings up the Run on Server wizard. Proceed through the wizard as follows:
- For the Server's host name, select localhost. For the server type, expand the Apache folder and select Tomcat V5.5. For the server runtime, select Apache Tomcat V5.5.
By default Tomcat version 5.5 or higher requires Java 5 (1.5) or higher. However, you can use Java 1.4 by following the instructions in RUNNING.txt included in the Tomcat distribution. In this example, I have a 1.5 version of the JDK installed. Tomcat will fail to start if you are not using a 1.5 version of Java, or you have not configured it to use 1.4.Next, check the Set server as project default checkbox. Click the Next button.
- In the Add and Remove Projects window, verify that the LowFareAir project is listed in the Configured Projects area. If it is not, and it appears in the Available Projects category, move it to the Configured Projects category. Click Finish.
This will start the external Tomcat server and launch a browser window to run the JSP on. For Windows, the default is to launch an internal browser from within Eclipse. On Linux it will default to the external browser.
To configure the launch of an external browser:
- Select Window > Preferences.
- Select the General tree item, then Web Browser.
- Select the Use external Web browser button, then choose from the browsers available in the list.
- Click OK to set the preference.
It is always a good idea to check your Web pages with different browsers. They do behave differently when rendering some HTML elements, as well as in their default handling of cookies.
As described above, the first time you launch Welcome.jsp, it will redirect you to the Register.jsp page. The derbyCookie has not been set, so Welcome.jsp redirects you to Register.jsp to create a user ID and password. See Figure 12.
Figure 12. Register.jsp with new user ID entry
When you enter a user ID and password and click the Register New User button, the values are passed to the LoginServlet class. Open up this Java class now, located under the LowFareAir > Java Resources > JavaSource > com.ibm.sample folder and package structure.
The doPost method first parses the incoming parameters, including the user ID and password you just set in Register.jsp.
Listing 9. The doPost method of the LoginServlet class
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String user = request.getParameter("username"); String password = request.getParameter("password"); // Register.jsp set the parameter newuser String newUser = request.getParameter("newuser"); String loggedOut = request.getParameter("loggedOut");
Then it connects to the Derby database by calling the
getConnInstance() method on the DerbyDatabase class. The
getConnInstance method returns a singleton
java.sql.Connection to the database.
Listing 10. Setting the conn variable to the singleton Connection object of the DerbyDatabase class
Connection conn = DerbyDatabase.getConnInstance();
The next section of code determines if the user is new or not, and either selects the user's ID from the database if they already exist, or adds it to the database if they do not.
Listing 11. Processing new users in the LoginServlet class
// the user is not new, so look up the username and password // in the APP.USERS table if (newUser == null || newUser.equals("")) { sql = "select * from APP.USERS where username = '" + user + "' and password = '" + password + "'"; String[] loginResults = DerbyDatabase.runQuery(conn, sql); // if the query was successful one row should be returned if (loginResults.length == 1) { validUser = true; } } // the user is new, insert the username and password into // the APP.USERS table else { sql = "insert into APP.USERS (username, password) values " + "('" + user + "', '" + password + "')"; int numRows = DerbyDatabase.executeUpdate(conn, sql); if (numRows == 1) { validUser = true; } }
To verify that the user ID Susan was added to the APP.USERS table, bring up
ij, the SQL tool from the Derby plug-in, to query the APP.USERS table.
To bring up
ij, right-click the LowFareAir folder, then select Apache Derby > ij (Interactive SQL). Connect to the
airlinesDB database by issuing this connect statement from
ij and running the query
select * from APP.USERS; to see if the user ID you entered into your browser appears. In this example, the user ID is Susan.
Note: Version 3.1 of Eclipse has different behaviour than previous versions in regards to where the cursor is in the console view. The cursor is always positioned at the beginning of the line. Although it looks a little odd, if you start typing at the ij prompt, the cursor will reposition to the correct location, right after the 'j' in ij.
Listing 12. Connecting to the airlinesDB database
connect 'jdbc:derby://localhost:1527/airlinesDB'; select * from APP.USERS;
The output from
ij is shown below.
Figure 13. ij results from APP.USERS table
Register.jsp passed those values correctly and LoginServlet.java inserted the user ID and password correctly into the table. The user ID and password of 'slc' and 'slc' were already in the table.
The rest of the code in LoginServlet.java deals with incorrect user IDs and passwords, and then forwards the results to Welcome.jsp if everything is correct. The next image shows Welcome.jsp with an Origin of Albuquerque and a Destination of Los Angeles. Note that the user ID was passed from LoginServlet.java to Welcome.jsp for display.
Figure 14. Welcome.jsp after successful login
Welcome.jsp posts to CheckFlightsServlet.java. Open up CheckFlightsServlet.java. The notable thing about this servlet is that after parsing the incoming parameters, it calls the
DerbyDatabase method
origDestFlightList(). This method returns an array of
FlightsBean objects.
Listing 13. The CheckFlightsServlet class
Connection conn = DerbyDatabase.getConnInstance(); FlightsBean[] fromToFlights = \ DerbyDatabase.origDestFlightList(conn, from, to);
Once the
FlightsBean array has been populated,
CheckFlightsServlet places the results in the session with the variable name of
fromToFlights.
Listing 14. Placing the array of FlightsBean into the session object
request.getSession().setAttribute("fromToFlights", fromToFlights);
Now open the DerbyDatabase.java class to see what this method does. Some of the code has been slightly reformatted for ease of viewing.
Listing 15. Examining the origDestFlightList method in the DerbyDatabase class
public static FlightsBean[] origDestFlightList(Connection conn, \ String origAirport, String destAirport) { String query = "select flight_id, segment_number, orig_airport, " + "depart_time, dest_airport, arrive_time, meal, flying_time, miles," + "aircraft from app.flights where ORIG_AIRPORT = ? AND " + "DEST_AIRPORT = ?"; List list = Collections.synchronizedList(new ArrayList(10)); try { PreparedStatement prepStmt = conn.prepareStatement(query); prepStmt.setString(1, origAirport); prepStmt.setString(2, destAirport); ResultSet results = prepStmt.executeQuery(); while(results.next()) { String flightId = results.getString(1); String segmentNumber = results.getString(2); String startAirport = results.getString(3); String departTime = results.getString(4); String endAirport = results.getString(5); String arriveTime = results.getString(6); String meal = results.getString(7); String flyingTime = String.valueOf(results.getDouble(8)); String miles = String.valueOf(results.getInt(9)); String aircraft = results.getString(10); list.add(new FlightsBean(flightId, segmentNumber, startAirport, departTime, endAirport, arriveTime, meal, flyingTime, miles, aircraft)); } results.close(); prepStmt.close(); } catch (SQLException sqlExcept) { sqlExcept.printStackTrace(); } return (FlightsBean[])list.toArray(new FlightsBean[list.size()]); }
The
origDestFlightList method issues an SQL query using a PreparedStatement, and places the results in a
FlightsBean[] array. One of the
FlightsBean constructors is shown below.
Listing 16. One of the FlightsBean constructors
public FlightsBean(String flight_id, String segNumber, String origAirport, String depart_time, String destAirport, String arrive_time, String food, String flying_time, String mile, String jet) { flightId = flight_id; segmentNumber = segNumber; startAirport = origAirport; departTime = depart_time; endAirport = destAirport; arriveTime = arrive_time; meal = food; flyingTime = flying_time; miles = mile; aircraft = jet; }
Once the
origDestFlightList method populates the
FlightsBean array, processing continues in the CheckFlightsServlet servlet and the results are forwarded to the GetFlights.jsp page.
In the next section, you'll use the JSP debugger feature of the WTP to look at the values returned in the
FlightsBean when selecting a flight.
The next section will start the Tomcat server in debug mode, so go ahead and stop it now. To do this, select the Servers view tab in the lower right section of the workspace. Then right-click in the Tomcat server line and select Stop.
Figure 15. Stopping the Tomcat server from the WTP Servers view
Using the JSP debugger
Stepping back from the code a minute, here is a summary of what you have seen by exploring and configuring the sample application:
- WTP
- Used the Database Explorer view to configure a connection to a Derby 10.1 database using the Derby Client driver.
- Sampled the contents of the FLIGHTS table from the Database Explorer view.
- Added a row to the FLIGHTS table from the Database Explorer view, using the Data > Open menu option.
- Started the Tomcat server using the Run As > Run On Server option from a JSP file.
- Opened and examined a JSP in the JSP editor.
- Stopped the Tomcat server using the Servers view.
- Derby plug-in
- Added the Apache Derby nature to a Dynamic Web Project.
- Configured Derby system properties using the Project Properties menu.
- Ran entire SQL scripts via ij.
- Issued SQL commands via ij.
- Started and stopped the Derby Network Server.
Now let's look at the JSP debugging capabilities of the WTP.
At this point there is at least one valid user in the Derby
airlinesDB APP.USERS table, and you may have added another. Before you run through the application again, set a breakpoint in the GetFlights.jsp page first, and then start the Tomcat server in debug mode.
To set the breakpoint, open GetFlights.jsp, and right-click in the grey area to the left of the line of code which starts with
<c:set var="myradiobutton". Select Toggle Breakpoints as shown below.
Figure 16. Setting a breakpoint in GetFlights.jsp
The breakpoint will appear as a blue dot in the grey area on the left. Now from the Project Explorer (making sure the Derby Network Server is still running), right-click Welcome.jsp and select Debug As > Debug On Server. The Tomcat server will now start up in Debug mode and bring up the Welcome.jsp page prompting for a user ID and password.
Enter the user ID and password you entered previously, or a user ID value of
slc with a password of
slc. If you did not delete the cookie already set, you will be allowed to select a flight from Welcome.jsp without having to log in again. Not all of the flights listed in the Origin to Destination are direct. Select an Origin of Albuquerque and a Destination of Los Angeles, since that flight is direct. Then finish by clicking Submit Query.
At this point, Eclipse should prompt you to switch to the Debug perspective. Confirm the perspective switch. When the debug perspective appears, the Variables view on the upper right of the workspace will appear. In the bottom left, the GetFlights.jsp editor view will also appear, showing where you set the breakpoint.
The Variables view may not be populated with values immediately. You might need to go to the Debug view and select the thread that has been suspended. Once you expand the suspended thread and select GetFlights.jsp in the Debug view as shown below, the Variables view should be populated.
In the Variables view, look for your core JSTL
when tag. Expand the tree for the
_jspx_th_c_when_0=WhenTag item. See Figure 17.
Figure 17. Examining variables from the JSP debug perspective
Notice the reference to the parent tag
ChooseTag from within the
WhenTag. Expand the parent
ChooseTag, and contained within it is the parent
ForEachTag. Expand that
ForEachTag and finally expand the item variable which equals
FlightsBean. If you have been successful in following this, your Variables view will look something like what is shown below.
Figure 18. FlightsBean values in Debug mode
This shows the values set in the FlightsBean object, which were selected with a departing airport of Albuquerque and a destination airport of Los Angeles. The JSP debugger can be extremely useful when troubleshooting Web applications, and in particular in examining variables as shown here.
Now click the Resume button on the top left menu item, which looks like a green arrow, to step past the breakpoint. The browser will display the output of the GetFlights.jsp page. In the browser, select the available flight (flight number AA1111), and click the Book Flight button.
The next page gives you one last chance to either book the flight or check for other flights. Go ahead and click the Book Flight button. The next page will appear similar to what is shown below.
Figure 19. Flight History
When you clicked Book Flight on the previous screen, a row was inserted into the APP.FLIGHTHISTORY table. Since you have learned how to use both ij and the Database Explorer, you can verify that the row was actually inserted into the table.
At this point in the application, the user can either return to select a new flight, or log out of the application.
Summary
In setting up and configuring the WTP platform, you have used the external Tomcat server, debugged a JSP file, configured a connection to a 10.1 Derby database using the Database Explorer, and used the Database Explorer to browse a table and insert a row.
You've learned about the use of the Derby plug-ins, including adding the Apache Derby nature, starting and stopping the Network Server, using ij to run SQL scripts and issue ad-hoc commands, as well as setting the
derby.system.home property.
You configured the web.xml file for the Web application to use Derby as a data source.
Finally, you used the JSTL SQL tag library to issue queries against the Derby database you configured as a data source.
I hope this article has provided a solid foundation for using the numerous tools available within WTP and the Derby plug-ins. Starting from these fundamentals, you can develop robust Web applications using Derby as the data store.
Downloads
Resources
Learn
- Derby: The Apache Derby site contains online documentation, downloads (source and binary), and integration information with other open source projects. Both a developers and users mailing list is available to subscribe to or browse as archives.
- Derby Plug-ins: The Apache Derby Integration area contains a section, Eclipse Plug-ins, which has a brief presentation on the Derby plug-ins and a Lab on how to use them available for download.
- JSTL: An excellent series of articles on developerWorks, A JSTL primer, is a great place to start learning about the JSTL.
- WTP: The WTP Web site is host to all things WTP. In particular, the tutorials are helpful and subscribing to the newsgroup can help when problems are encountered.
- The Cloudscape information center contains all of the Cloudscape documentation on-line.
- developerWorks provides numerous technical articles related to Cloudscape.
Get products and technologies
- Eclipse WTP project: Download Eclipse 3.1.1 and WTP 1.0 as a single bundle.
- Apache Derby Core and UI plug-ins: Download the Derby Core 10.1.2 and UI 1.1.0 plug-ins as zip files from the Distribution section.
- Apache Tomcat: Download Apache Tomcat, version 5.5.15.
- Apache Jakarta Project: Download the Apache Jakarta Standard 1.1 Taglibs.. | http://www.ibm.com/developerworks/data/library/techarticle/dm-0509cline/index.html | CC-MAIN-2014-49 | refinedweb | 8,309 | 57.67 |
QT I want to increase the size of comboBox Down list not the drop- Down icon ?
I have a combo box and i want to change (increase) the size of the down list. That contain all description index value visible.
Initially I am getting this one output.
But i want output like this
Also I want to remove the icon index that is showing inside the down list. Here is my code.
QIcon icon = QIcon::fromTheme("C:/Users/DragDrop/black-play-button.jpg"); QString label = ""; ui->comboBox->addItem( icon,label ); ui->comboBox->setMinimumWidth(100); ui->comboBox->setIconSize(QSize(40, 40)); ui->comboBox->setDisabled(false); ui->comboBox->addItem("Fill viewport ctrl+0"); ui->comboBox->addItem("100% ctrl+1"); ui->comboBox->addItem("200% ctrl+2"); ui->comboBox->addItem("400% ctrl+3"); ui->comboBox->addItem("800% ctrl+4");
Hi
You can set size via the model. (pr item)
#include <QtGui>
#include <QApplication>
#include <QComboBox>
int main(int argc, char **argv)
{
QApplication app(argc, argv);
QComboBox cb;
cb.addItems(QStringList() << "a" << "b" << "c" << "d");
cb.model()->setData(cb.model()->index(0, 0), QSize(100, 100), Qt::SizeHintRole);
cb.show();
return app.exec();
}
You can also use a stylesheet.
@mrjj when i use one code :-
ui->comboBox->model()->setData(ui->comboBox->model()->index(0, 0), QSize(100, 100), Qt::SizeHintRole);
this one just increase the size icon index size not the down list width.
Also I dont want to show the icon inside the drop list.
@amarism
Hi
It sets the Items Height.
Just make all items bigger and dropdown also be bigger.
Sample just sets item 0,0. you need set on all items.
@mrjj said in QT I want to increase the size of comboBox Down list not the drop- Down icon ?:
Just make all items bigger and dropdown also be bigger.
Sorry i am not getting this thing. item bigger and dropdown bigger. But I want only item width bigger
@amarism
Just adjust to what u want
QSize(100, 100) is the size. 100 width, 100 height
But the width of the drop-down is the width of the combo itself
@mrjj I don't want to increase the size of header combo box . Becaue i am using combobox as a button in my ui viewer. So, I can't set button size this much. I want the combo Box like this
@amarism
ok.
you need to subclass for that i think.
Alternatively, you canuse toolbutton and QMenu.
@amarism
I dont know what u mean.
Link talks about overriding showPopup to alter size.
That should do it.
- jsulm Lifetime Qt Champion last edited by
@amarism
In what way did it not work for you ?
Seems to work as expected.
class WideComboBox : public QComboBox { Q_OBJECT public: explicit WideComboBox(QWidget *parent = nullptr) : QComboBox(parent) {}; ~WideComboBox() {} public: void showPopup() { this->view()->setMinimumWidth(this->view()->sizeHintForColumn(0)); QComboBox::showPopup(); } };
setting it to 400 ;)
- J.Hilk Moderators last edited by
Additionally to what @mrjj wrote, you should also be able to set the size of the view via a StyleSheet, a viable option if you don't plan to vary the size all to often
ui->comboBox->setStyleSheet("QComboBox QAbstractItemView {min-width: 400px;}"),
can i add the vertical spacing between the rows
@J.Hilk One more problem comes here, I am added a icon for combo box . And it will showing inside the dropdown popup. can i hide from icom from dropdown button
- J.Hilk Moderators last edited by
@amarism I don't think you can do that via the StyleSheet. My guess would be to subclass QComboBox and override the
paintEventand ignore the
Qt::DecorationRole!? | https://forum.qt.io/topic/94277/qt-i-want-to-increase-the-size-of-combobox-down-list-not-the-drop-down-icon | CC-MAIN-2022-33 | refinedweb | 599 | 67.65 |
NAME | SYNOPSIS | DESCRIPTION | RETURN VALUES | ERRORS | ATTRIBUTES | SEE ALSO | NOTES
#include <sys/types.h> #include <sys/stat.h>int chmod(const char *path,.
Upon successful completion, chmod() and fchmod() mark for update the st_ctime field of the file.
Upon successful completion, 0 is returned. Otherwise, -1 is returned, the file mode is unchanged, and errno is set to indicate the error.
The chmod() function will fail if:
Search permission is denied on a component of the path prefix of path.
The path argument points to an illegal address.
A signal was caught during execution of the effective user ID does not match the owner of the file and is not super-user.
The file referred to by path resides on a read-only file system.
The fchmod() function will fail if:
The fildes argument is not an open file descriptor
An I/O error occurred while reading from or writing to the file system.
A signal was caught during execution of the fchmod() function.
The path argument points to a remote machine and the link to that machine is no longer active.
The effective user ID does not match the owner of the file and the process does not have appropriate privilege.
The file referred to by fildes resides on a read-only file system.
See attributes(5) for descriptions of the following attributes:
chmod(1), chown(2), creat(2), fcntl(2), mknod(2), open(2), read(2), rename(2), stat(2), write(2), mkfifo(3C), attributes(5), stat(3HEAD)
Programming Interfaces Guide
If you use chmod().
NAME | SYNOPSIS | DESCRIPTION | RETURN VALUES | ERRORS | ATTRIBUTES | SEE ALSO | NOTES | http://docs.oracle.com/cd/E19683-01/817-0661/6mgeq2src/index.html | CC-MAIN-2015-11 | refinedweb | 267 | 65.42 |
Download source files - 100 Kb
Hello, A few days back I was trying to design and develop a session object(a stand alone class) dealing with asp.net session varibales.The problem I faced was if I create a stand alone class in a project and assigned property’s to it(variables which I wanted to persist) ,and instantiate that class from the global.asax session start event ,this looked pretty fine in the beginning as I was only using these variables in the code behinds, but when I tried accessing these variables from other classes in the application, I couldn’t do it ,because the object was not in the same context (System.Web.HttpContext).So I did some research here and there and decided to use the singleton design patternto solve this problem. If you are new to this pattern you should read this article on msdn .
()
So I created a stand alone class Smart_Session and assigned property methods to it. And a static method which gets the object out of the session and returns it to the caller (both aspx and .cs files).And this class always returns a single instance at any call.
The code below is an example of one such class and can be referred to in code as per the following code:
<P>public class someclass</P>
<P>{
Smart_Session oSession = Smart_Session.GetCurrentSmart_Session();
<P>public string someMethod()
</P>
<P> <P>{
<P>
<P>oSession.Get_Set_Get_Set_prod_id =007;
<P>}</P>
<P>}
</P>
Example of Smart_Session
<PRE>public class Smart_Session
{
private const string SMART_SESSION = "SESGLOBAL";
private bool init;
private string user_name;
private string user_pwd;
private int lang_id;
private int acc_id;
private string purch_id;
private int purch_date;
private int serial_no;
private string prod_id;
private string pkg_id;
private string err_msg;
private string email_id;
private Smart_Session()
Refresh();
}
public void Refresh()
this.prod_id = "";
this.serial_no = 0;
this.purch_date = 0;
this.purch_id = "";
this.acc_id = 0;
this.lang_id = 0;
this.pkg_id = null;
this.init = false;
this.err_msg = "";
this.email_id="";
public string GetSetEmailID
get
return this.email_id;
set
this.email_id = value;
public string GetSetPassword oSmart_Session;
There are many advantages to using singleton objects stored in the Session object rather than using individual session keys for storing information. It is useful for objects that are meant to exist for the entire session (grouping logical items, impact analysis, intellisense, etc) and especially for objects that are really only needed for a period of time on a web site until the user completes a particular process (much easier to identify misuse of variables and to conserve resources when the process is completed but the session will. | http://www.codeproject.com/Articles/7248/using-the-singleton-design-pattern-for-managing-se?fid=55574&df=90&mpp=10&sort=Position&spc=None&tid=1161781 | CC-MAIN-2014-35 | refinedweb | 428 | 61.67 |
What is Laravel?
Laravel is a structure that allows a user to choose and create programs. Everything from giving a form to the software and joining it with different application programs is covered by Laravel. It is a freely available PHP framework with a focus on writing codes that help to create personalized web software quickly and efficiently.
What are the pros and cons of using the Laravel Framework?
The pros and cons of the Laravel Framework are:
Pros
- The blade template engine speeds up tasks like a compilation and allows users to add the latest features easily.
- “Bundled modularity” allows reuse of code without any trouble.
- It is easy to understand and create database relationships.
- The Artisan CLI comprising advanced tools for task and migrations.
- The documentation allows reverse routing.
Cons
- It can be slow.
- It is a new platform for many developers.
- It gets difficult to extend codes and classes for amateurs.
- Limited community support compared to other platforms.
- Reverse routing and other methods are pretty complicated.
Describe Events in Laravel?
Events in Laravel are observer implementations that allow subscription to events as well as listen to updates about different events within the application. The event classes are saved in the app/Events directory and the listeners are saved in app/Listeners. They may be generated with the help of Artisan console commands. They go a long way in decoupling several aspects of an application due to the multiplicity of listeners for a single event.
How to check Laravel version?
The steps to check the version of Laravel is-
- Open the folder Vendor.
- Go to Laravel and then to Framework.
- In SRC, click on Illuminate.
- Open Applications from Foundation.
- The version will be displayed here.
What are Validations?
Validations are approaches used by Laravel to validate incoming data within an application. The base controller class of Laravel uses the trait ValidatesRequests by default to validate an incoming HTTP request with the help of powerful validation rules.
How to create a controller in Laravel?
The syntax used to create a controller in Laravel is as follows-
<?php namespace AppHttpControllers; use AppUser; use AppHttpControllersController; class UserController extends Controller { /** * Show the profile for the given user. * * @param int $id * @return View */ public function show($id) { return view('user.profile', ['user' => User::findOrFail($id)]); } }
How to remove public from URL in Laravel?
The steps to remove the public from URL in Laravel are-
- Rename the file in the Laravel root directory.
- Update the .htaccess in the root folder using the code-...]
What is middleware in Laravel?
Middleware in Laravel is a bridge that connects request to a response. It filters and verifies the authentication of the user of the application. Only the authenticated users are redirects to the home page.
How to update composer in Laravel?
The steps to update the composer in Laravel are:
- In the composer.json file at the root of your git repo, run the composer update.
- Re-generate the composer.lock file.
- Transfer the composer.lock file to the git repository.
- Click on 'Tools in the Engine Yard Cloud' and go to Dashboard.
- Select an environment name.
- Click on Deploy.
How to run Laravel project in xampp?
The steps to run Laravel in xampp are-
- Instal xampp in C drive.
- Create a Laravel folder in htdocs under the xampp folder in C drive.
- Redirect to Laravel with cmd prompt.
- Use the below command
composer create-project laravel/laravel first-project --prefer-dist
- Redirect to localhost/laravel/first-project/public/.
How to clear cache in Laravel?
The syntax to clear cache in Laravel is:
- php artisan cache: clear
- php artisan config: cache
- php artisan route: cache
What is homestead Laravel?
Laravel Homestead is the official, pre-packaged, disposable Vagrant box that delivers a development environment to use without the additional need to install PHP, a web server, or any other server software on the machine.
What is namespace in Laravel?
Namespace in Laravel allows a user to group the functions, classes and constants under a specific name.
How to use curl in Laravel?
The step to use curl in Laravel are:
- Add the curl package to run curl request method on the cmd or terminal.
- Create a route from routes/web.php file to get curl request.
- Add a different getCURL() in HomeController.
- It can be used to run post, put, patch, and delete request.
What is facade in Laravel?
A facade in Laravel is a class that allows static-like interface for the services in a container. They serve as a proxy, depending on the documentation, to access the core implementation of the services of the container.
What is Laravel Route?
A Route is a process which is used to send all your application URL to the associated controller function. The most primary or basic routes in Laravel simply take URI and its Closure.
What is a migration in Laravel?
Migrations in Laravel refer to files that comprise of class definitions along with an up() and down() method. The up() method is executed when the relates to changes in the database while the down() method helps to undo the changes.
Note: To update databases, new migrations must be created.
What is CSRF token in Laravel?
Cross-Site Forgery or CSRF in Laravel detect unauthorized attacks on web applications. by the authenticated users of a system. The built-in CSRF plug-in created CSRF tokens to verify all operations and requests sent an active authenticated user.
What is Eloquent ORM in Laravel?
The Eloquent ORM in Laravel is a built-in ORM implementation that permits working database objects and relationships through eloquent and easy-to-read syntax. It assumes the id as the primary key for a record and that the model is representing a table with an id field.
What is Laravel Forge?
Laravel Forge is a tool that helps in organising and designing a web application. Although the manufacturers of the Laravel framework developed it, it can automate the deployment of every web application that works on a PHP server.
What are the differences between Codeigniter and Laravel?
The differences between Codeigniter and Laravel are-
How to create middleware in Laravel?
The command used to create middleware in Laravel is:
php artisan make: middleware <middleware-name>. | https://www.stechies.com/laravel-interview-questions/ | CC-MAIN-2021-17 | refinedweb | 1,040 | 59.8 |
hi allan
please remember to prefix with [digester]. most folks use mail filters
and this thread is in danger of getting lost...
i'd strongly suggest changing the name of this thread as soon as
possible but here something to start you off: there is no answer as to
whether you should set namespace on or off in this case. it's a tradeoff
and the right trade depends on the particulars of the case. see
for more information.
- robert
On Thu, 2005-02-17 at 20:51, Allan Axon wrote:
> I'm trying to use the digester with a rules.xml file. The xml file I am
> parsing looks like this:
>
> <?xml version="1.0" encoding="ISO-8859-1" ?>
> <SOAP-ENV:Envelope xmlns:SOAP-ENV ... >
> <SOAP-ENV:Body>
> <Ob xmlns:obns=...>
> <ObProfile>
> <ObPanel att1=...>
> ....
> </Ob>
> </SOAP-ENV:Body>
> </SOAP-ENV:Enveloper>
>
> My patterns look like this "SOAP-ENV:Envelope/SOAP:Body/Oblix/ObProfile"
> when digester.setNamesspaceAware(false). Is this the correct pattern?
>
> Could I use the obns with digester.setNamespaceAware(true) and
> digester.setRuleNamespaceURI(obnsURI) and use a pattern like:
> Ob/Obprofile/ObPanel even though none to the elements in the body have
> <obns:Element> forms. Does this mean the obns namespace is not being
> used or that it applies to everything below the Ob node?
>
> When I run my digester I'm trying to test it by running a public method
> for the ObProfile object and I get a NullPointerException which I assume
> means that my patterns are not matching correctly in the xml file.
>
> Thanks,
> Allan Axon
> NC DENR
---------------------------------------------------------------------
To unsubscribe, e-mail: commons-user-unsubscribe@jakarta.apache.org
For additional commands, e-mail: commons-user-help@jakarta.apache.org | http://mail-archives.apache.org/mod_mbox/commons-user/200502.mbox/%3C1108682060.2391.80.camel@knossos.elmet%3E | CC-MAIN-2017-26 | refinedweb | 283 | 58.38 |
DiceRoller app from the last codelab and learn how to add and use image resources in your app. You also learn about app compatibility with different Android versions and how the Android Jetpack can help.
res) directory and Gradle build files.
In this codelab, you build on the DiceRoller app you started in the previous codelab, and you add dice images that change when the die is rolled. The final DiceRoller app looks like this:.
resfolder. The
drawablefolder is where you should put all the image resources for your app. Already in the
drawablefolder you can find the resources for the app's launcher icons.
DiceImagesfolder into Android Studio and onto the drawable folder. Click OK.
dice_1.xml, and notice the XML code for this image. Click the Preview button to get a preview of what this vector drawable actually looks like.
Now that you have the dice image files in your
res/drawables folder, you can access those files from your app's layout and code. In this step, you replace the
TextView that displays the numbers with an
ImageView to display the images.
activity_main.xmllayout file if it is not already open. Click the Text tab to view the layout's XML code.
<TextView>element.
.
MainActivity. Here's what the
rollDice()function looks like so far:
private fun rollDice() { val randomInt = Random().nextInt(6) + 1.
resultTextvariable and set its text property. You're no longer using a
TextViewin the layout, so you don't need either line.
findViewByID()to get a reference to the new
ImageViewin the layout by ID (
R.id.dice_image), and assign that view to a new
diceImagevariable:
val diceImage: ImageView = findViewById(R.id.dice_image)
whenblock to choose a specific die die image resource within that folder.
ImageViewwith the
setImageResource()method and the reference to the die image you just found.
diceImage.setImageResource(drawableResource).
onCreate(), after the
setContentView()method, use
findViewById()to get the
ImageView.
diceImage = findViewById(R.id.dice_image)
rollDice()that declares and gets the
ImageView. You replaced this line with the field declaration earlier.
val diceImage : ImageView = findViewById(R.id.dice_image)
Right now you are using
dice_1 as the initial image for the die. Instead, say, you wanted to display no image at all until the die is rolled for the first time. There are a few ways to accomplish this.
activity_layout.xmlin the Text tab.
.
activity_layout.xml, copy the
android:srcline,.
<LinearLayout>element at the root of the layout file, and notice the two namespaces defined here.
<LinearLayout xmlns:android="" xmlns:tools="" ...
tools:srcattribute in the
ImageViewtag to be
dice_1instead of
empty_dice:
android:
Notice that the
dice_1 image is in place now as the placeholder image in the preview..
androidsection towards the top of the
build.gradlefile. ).
targetSdkVersionparameter, which is inside the
defaultConfigsection:
targetSdkVersion 28
This value is the most recent API that you have tested your app against. In many cases this is the same value as
compileSdkVersion..
MainActivity.
MainActivityclass extends not from
Activityitself, but from
AppCompatActivity.
class MainActivity : AppCompatActivity() { ...
AppCompatActivity is a compatibility class that ensures your activity looks the same across different platforms OS levels.
importto expand the imports for your class. Note that the
AppCompatActivityclass is imported from the
androidx.appcompat.apppackage. The namespace for the Android Jetpack libraries is
androidx..
You're going to use your new knowledge about namespaces, Gradle, and compatibility to make one final adjustment to your app, which will optimize your app size on older platforms.
defaultConfigsection:
vectorDrawables.useSupportLibrary = true
build.gradlefile is modified, you need to sync the build files with the project.
main_activity.xmllayout file. Add this namespace to the root
<LinearLayout>tag, underneath the
toolsnamespace:
xmlns:app=""
The
app namespace is for attributes that come from either your custom code or from libraries and not the core Android framework..
Android Studio project: DiceRollerFinal
Challenge: Modify the DiceRoller app to have two dice. When the user taps the Roll button, each die should have a value independent of the other.
Tip: Create a new private function to get a random drawable image and return an integer for the drawable resource. Use that function for each of the die images.
private fun getRandomDiceImage() : Int { ... }
Android Studio project: DiceRollerFinal-challenge
App resources:
resfolder.
drawableresources folder is where you should put all the image resources for your app.
Using vector drawables in image views:
<ImageView>element. The source of the image is in the
android:srcattribute. To refer to the drawable resource folder, use
@drawable, for example
"@drawable/image_name".:
findViewById()in your code by declaring fields to hold those views, and initializing the fields in
onCreate(). Use the
lateinitkeyword for the field to avoid needing to declare it nullable.
The
tools namespace for design-time attributes:
tools:srcattribute in the
<ImageView>element in your layout to display an image in only Android Studio's preview or design editor. You can then use an empty image for
android:srcfor the final app.
toolsnamespace in the Android layout file to create placeholder content or hints for layout in Android Studio. Data declared by
toolsattributes is not used in the final app.
API levels:
compileSdkVersionparameter in the
build.gradlefile specifies the Android API level that Gradle should use to compile your app.
targetSdkVersionparameter specifies the most recent API level that you have tested your app against. In many cases this parameter has the same value as
compileSdkVersion.
minSdkVersionparameter specifies the oldest API level your app can run on.
Android Jetpack:
androidxpackage refer to the Jetpack libraries. Dependencies to Jetpack in your
build.gradlefile also start with
androidx.
Backward compatibility for vector drawables:
vectorDrawables.useSupportLibrary = trueconfiguration parameter in the
build.gradlefile.
app:srcCompatattribute in the
<ImageView>element (instead of
android:src) to specify the vector drawable source for that image.
The
app namespace:
appnamespace in your XML layout file is for attributes that come from either your custom code or from libraries, not from the core Android framework.
Udacity course:
Android developer documentation:
ImageView
findViewById
() Clear button to the DiceRoller app that sets the die image back to the empty image.
Which
<ImageView> attribute indicates a source image that should be used only in Android Studio?
android:srcCompat
app:src
tools:src
tools:sourceImage
Which method changes the image resource for an
ImageView in Kotlin code? xmx
setImageResource()
setImageURI()
setImage()
setImageRes()
What does the
lateinit keyword in a variable declaration indicate in Kotlin code?
null.
Which Gradle configuration indicates the most recent API level your app has been tested with?
minSdkVersion
compileSdkVersion
targetSdkVersion
testSdkVersion
You see an import line in your code that starts with
androidx. What does this mean?
Check to make sure the app has the following:
R.drawable.empty_dice.
Start the next lesson:
For links to other codelabs in this course, see the Android Kotlin Fundamentals codelabs landing page. | https://codelabs.developers.google.com/codelabs/kotlin-android-training-images-compat/index.html?index=..%2F..android-kotlin-fundamentals | CC-MAIN-2019-43 | refinedweb | 1,124 | 50.12 |
GPy LTE-M Connection
Hi All,
Is There a way to use the LTE-M module to send data to io.adafruit.com?
BR
@livius Regards first question: i used the code here:...
But I did not have any results...The country is Italy and I have the tim sim..
BR
@francesco-gallo
First question is - do you have succesfully connected to LTE CAT M1?
If yes, which provider do you use and in which location (country)
For sensors you can use any code sample existed for e.g. wifi
only difference is start point (connection to the network)
next steps are the same create socket and send data
you can use e.g. urequest
e.g.
import urequests res = urequests.post('your_service_url', json={'MyTemerarureSensorName': str(temp)}) res.close() if (res.status_code - 200) < 100: print("post ok:" + str(temp) + " C") else: print('some error')
@livius Thanks...
The update is done...and now is ok..
My question is about an example code regards the use of LTE to send temperature value to online service, or send the temperature value to smartphone...
BR
@francesco-gallo said in GPy LTE-M Connection:
Is there an example code?
example of what? Updating firmware?
after this step we can go next :)
@livius And please, I am a newbie :(.. And I would like learn as send data (e.g. Temperature) using LTE...
Is there an example code?
@francesco-gallo
update device because docs fallow firmware and in 1.17 there was big change in LTE
@francesco-gallo
What is your firmware version?
import os os.uname()
you should have
1.17.0.b1
@francesco-gallo And please, I am a newbie :(.. And I would like learn as send data (e.g. Temperature) using LTE...
Is there an example code?
BR
@francesco-gallo said in GPy LTE-M Connection:
How can modify the example from this link?
Back to my first question. You do not know how to send something to io.adafruit.com
not how to send something throught LTE-M1?
Because sample you provided is exacly for LTE-CAT M1 (and there is no diiference between wifi and socket usage)
use api provided
and send http request by e.g. urequest
@livius Hi @livius , thank you for your interest.
My idea is to use the LTE-M module with my SIM to send data (e.g. Temperature Value) to a service like io.adafruit.com.
I don't want to use Wi-fi...How can modify the example from this link?
BR
@francesco-gallo
You ask about LTE-M or generic problem with send to
io.adafruit.com?
I suppose that about sending at all. Because there is not difference between wifi and LTE socket use | https://forum.pycom.io/topic/2748/gpy-lte-m-connection | CC-MAIN-2019-30 | refinedweb | 451 | 78.45 |
07 September 2010 15:25 [Source: ICIS news]
TORONTO (ICIS)--?xml:namespace>
The decline is a sign of slowing growth rates after a strong second-quarter for
The ministry said July’s sequential decline was largely due to below-average “big ticket” orders which hit producers in the investment goods sector.
On a two-month sequential comparison – June/July versus April/May – orders were up 2.4%, largely driven by orders from abroad, the ministry said.
Compared with June/July 2009, orders were up 21.2%.
Meanwhile,
The recent double-digit year-over-year growth in sales and production came against weak 2009 comparison periods, and continued growth at such rates could not be taken for granted, said Wiesbaden-based chemical employers trade group BAVC.
The group warned of continued challenges to the global and the German economy, including the effective regulation of financial markets, high government debts, and pressures on the economy from government’s efforts to cut debts.
Last | http://www.icis.com/Articles/2010/09/07/9391559/germany-industrial-orders-fall-2.2-in-july-ministry.html | CC-MAIN-2014-42 | refinedweb | 161 | 50.57 |
Help:Editing
Please note that the guide is an official guide, and as such, this page is subject to constant improvements. The community can make suggestions by utilizing the talk page. Because of the mechanism of MediaWiki (Special:RecentChanges), we won't have to announce any addition/deletion to the guide.
InstallGentoo Wiki is powered by MediaWiki, a free software wiki package written in PHP, originally designed for use on Wikipedia. More in-depth help can be found at Help:Contents on MediaWiki and Help:Contents on Wikipedia.
This is a short tutorial about editing the wiki. Before editing or creating pages, users are encouraged to familiarize themselves with the general tone, layout, and style of existing articles. An effort should be made to maintain a level of consistency throughout the wiki.
You must be logged-in to edit pages. Visit Special:UserLogin to log in or create an account. To experiment with editing, please use the sandbox. For an overview of wiki markup, see Help:Cheatsheet.
Contents
- 1 Editing
- 2 Creating pages
- 3 Formatting
- 4 Links
- 5 Redirects
- 6 Wiki variables, magic words, and templates
- 7 See also technology, /g/, or /tech/? and Help:Style#Title for article naming advice.
Also, your article should be informative, and the main things people will be looking for when browsing this wiki are:
- What is (insert topic here)?
- Why should I use (insert topic here)?
- How do I use (insert topic here)?
- Where can I get (insert topic here)?
and last but not least
- What (insert topic here) does /g/ use or recommend?
These are the questions you should try to answer while writing your article.
To add a new page to some category (say "My new page" to "Some category") you need to:
- Create a page with your new title by browsing to (remember to replace "My_new_page" with the intended title!)
- Add
[[Category:Some category]]to the bottom Linux article, use:
[[Linux]]
If you want to use words other than the article title as the text of the link, you can add an alternative name after the pipe "|" divider (
Shift +
\ on English-layout and similar keyboards).
For example:
[[GNU/Linux|Linux]] is mostly used by servers.
...is rendered as:
When you want to use the plural of an article title (or add any other suffix) for your link, you can add the extra letters directly outside the double square brackets.
For example:
See our list of [[List of recommended GNU/Linux software|recommended software]]s.
...is rendered as:
- See our list of recommended softwares.
Links to sections of a document
To create a link to a section of a document, simply add a
# followed by the section's heading.
For example:
[[Help:Editing#Links to sections of a document]]
...is rendered as:
Pipe trick
In some cases, it is possible to use the pipe trick to save writing the label of wiki links. The most important cases usable on the wiki are:
- In article titles, it allows to hide some stuff. For example,
[[Linux kernel|Linux]]is turned into Linux.
- In links to different namespace or wiki, the pipe trick hides the prefix. For example,
[[InstallGentoo Wiki:About|]]is turned into About and
[[wikipedia:Help:Pipe trick|]]is turned into Help:Pipe trick.
When the page is saved, the pipe trick will automatically generate the alternative text for the link and change the wikitext accordingly. link to the Wikipedia:Gentoo article you can use the following:
[[Wikipedia:Gentoo]]
Or you can create a piped link with an alternate link label to the Gentoo Wikipedia article:
[[Wikipedia:Gentoo|Gentoo Wikipedia article]]
See: Wikipedia:Interwiki links
The list of all interwiki links working on the wiki can be viewed here..
Note that redirecting an existing page to another can create double redirects, fix it. "InstallGentoo Wiki")..
See also
- Help:Article naming Name your article properly.
- Help:Style Styling guidelines for the wiki, so it can be consistent.
- Help:Discussion Discussion guidelines for talk pages.
- Help:Template For your templating needs. | https://wiki.installgentoo.com/index.php/Help:Editing | CC-MAIN-2017-17 | refinedweb | 667 | 55.54 |
New in version 2.2.15October 25th, 2014
- Plugins can now print a banner comment in doveconf output (typically the plugin version)
- Replication plugin now triggers low (instead of high) priority for mail copying operations.
- IMAP/POP3/ManageSieve proxy: If destination server can't be connected to, retry connecting once per second up to the value of proxy_timeout. This allows quick restarts/upgrades on the backend server without returning login failures.
- Internal passdb lookups (e.g. done by lmtp/doveadm proxy) wasn't returning failure in some situations where it should have (e.g. allow_nets mismatch)
- LMTP uses mail_log_prefix now for logging mail deliveries instead of a hardcoded prefix. The non-delivery log prefix is still hardcoded though.
- passdb allow_nets=local matches lookups that don't contain an IP address (internally done by Dovecot services)
- Various debug logging and error logging improvements
- Various race condition fixes to LAYOUT=index
- v2.2.14 virtual plugin crashed in some situations
New in version 2.2.14 (October 15th, 2014)
- Some of the more important fixes since RC1:
- Fixed several race conditions with dovecot.index.cache handling that may have caused unnecessary "cache is corrupted" errors.
- auth: If auth client listed userdb and disconnected before finishing, the auth worker process got stuck (and eventually all workers could get used up and requests would start failing).
- Some of the larger changes since v2.2 ports).Rawlog settings can use tcp:: as the path.virtual plugin: Don't keep more than virtual_max_open_mailboxes (default 64) number of backend mailboxes open.SSL/TLS compression can be disabled with ssl_options=no_compressionacl: Global ACL file now supports "quotes" around patterns.Added last-login plugin to set user's last-login timestamp on login.LDAP auth: Allow passdb credentials lookup also with auth_bind=yes
- IMAP: MODSEQ was sent in FETCH reply even if CONDSTORE/QRESYNC wasn't enabled. This broke at least old Outlooks.
- passdb static treated missing password field the same as an empty password field.
- mdbox: Fixed potential infinite looping when scanning a broken mdbox file.
- imap-login, pop3-login: Fixed potential crashes when client disconnected unexpectedly.
- imap proxy: The connection was hanging in some usage patterns. This mainly affected older Outlooks.
- lmtp proxy: The proxy sometimes delivered empty mails in error situations or potentially delivered truncated mails.
- fts-lucene: If whitespace_chars was set, we may have ended up indexing some garbage words, growing the index size unnecessarily.
- -c and -i parameters for dovecot/doveadm commands were ignored if the config socket was readable.
- quota: Quota recalculation didn't include INBOX in some setups.
- Mail headers were sometimes added to dovecot.index.cache in wrong order. The main problem this caused was with dsync+imapc incremental syncing when the second sync thought the local mailbox had changed.
- doveadm backup didn't notice if emails were missing from the middle of the destination mailbox. Now it deletes and resyncs the mailbox.
New in version 2.2.11 (February 12th, 2014)
- acl plugin: Added an alternative global ACL file that can contain mailbox patterns. See for details.
- imap proxy: Added proxy_nopipelining passdb setting to work around other IMAP servers' bugs (MS Exchange 2013 especially).
- Added %{auth_user}, %{auth_username} and %{auth_domain} variables. See for details.
- Added support for LZ4 compression.
- stats: Track also wall clock time for commands.
- pop3_migration plugin improvements to try harder to match the UIDLs correctly.
- imap: SEARCH/SORT PARTIAL reponses may have been too large.
- doveadm backup: Fixed assert-crash when syncing mailbox deletion.
New in version 2.2.10 (December 20th, 2013)
-.
New in version 2.2.9 (November 26th, 2013)
- Full text search indexing can now be done automatically after saving/copying mails by setting plugin { fts_autoindex=yes }
- replicator: Added replication_dsync_parameters setting to pass "doveadm sync" parameters (for controlling what to replicate).
- Added mail-filter plugin
- Added liblzma/xz support (zlib_save=xz)
- v2.2.8's improved cache file handling exposed several old bugs related to fetching mail headers.
- v2.2.7's iostream handling changes were causing some connections to be disconnected before flushing their output (e.g. POP3 logout message wasn't being sent)
New in version 2.2.8 (November 20th, 2013)
- Some usage of passdb checkpassword could have been exploitable by local users. You may need to modify your setup to keep it working. See
New in version 2.2.7 (November 4th, 2013)
- Some usage of passdb checkpassword could have been exploitable by local users. You may need to modify your setup to keep it working. See
- auth: Added ability to truncate values logged by auth_verbose_passwords (see 10-logging.conf comment)
- mdbox: Added "mdbox_deleted" storage, which can be used to access messages with refcount=0. For example: doveadm import mdbox_deleted:~/mdbox "" mailbox inbox subject oops
- ssl-params: Added ssl_dh_parameters_length setting.
-.
New in version 2.2.6 (September 26th, 2013)
- acl: If public/shared namespace has a shared subscriptions file for all users, don't list subscription entries that are not visible to the user accessing it.
- doveadm: Added "auth lookup" command for doing passdb lookup.
- login_log_format_elements: Added %{orig_user}, %{orig_username} and %{orig_domain} expanding to the username exactly as sent by the client (before any changes auth process made).
- Added ssl_prefer_server_ciphers setting.
- auth_verbose_passwords: Log the password also for unknown users.
- Linux: Added optional support for SO_REUSEPORT with inet_listener { reuse_port=yes }
-
New in version 2.2.5 (August 6th, 2013)
-.) | http://linux.softpedia.com/progChangelog/Dovecot-Changelog-5775.html | CC-MAIN-2014-52 | refinedweb | 886 | 51.14 |
Did you google around?
There are lot of links that can help you.
Don't use a div. HTML has <fieldset> and <legend> which are
designed for this usecase and render like that by default.
<fieldset>
<legend>Motor 1 Log</legend>
<label>Movements <input></label>
<label>Over-Currents <input></label>
<label>Amphous <input></label>
</fieldset>
you missed one line of code [self.view addSubview: label]; code should be
write like
UILabel* label = [[UILabel alloc] initWithFrame: labelFrame];
[label setText: @"My Label"];
[label setTextColor: [UIColor orangeColor]];
[self.view addSubview: label]
You have two options - a custom label control or a user control that
contains the label and the * based on a Mandatory property. If you have an
explicit need to make the "*" red (seems to be the case per your q), you
will need to use the user control. This is slightly heavier, so I would
recommend rethinking that requirement. Here's how the custom label control
would look:
public class CustomLabel : Label
{
public CustomLabel()
{
}
public bool Mandatory { get; set; }
public override String Text
{
get
{
return base.Text + " *";
}
}
}
You would now use the CustomLabel instead of the Label.
I'm answering this only because I think it's important to show what happens
when scope is confused. The reason you're having your issue is the scope
of your variables. Your label is changing iRow * iColumn times, but only
during initial execution. From then on, iRow and iColumn are fixed at
their final values.
To achieve your desired end goal, it'd be easiest to create an extension of
Panel:
public class ChessPanel : Panel {
private const Color HighlightColor = Color.Red;
public int iColumn { get; set; }
public int iRow { get; set; }
public Color PrimaryColor { get; set; }
public ChessPanel() : base()
{
this.MouseEnter += (s,e) =>
{
this.PrimaryColor = this.BackColor;
this.BackColor =
Try this (where ChartAreas["A"] = your ChartAreas(0)):
chart1.ChartAreas["A"].BackColor = Color.Gray;
chart1.BackColor = Color.Gray;
//
chart1.ChartAreas["A"].AxisY.LabelStyle.Font = new
System.Drawing.Font(chart1.ChartAreas["A"].AxisY.LabelStyle.Font,
FontStyle.Regular);
MessageBox.Show(chart1.ChartAreas["A"].AxisY.LabelStyle.Font.Bold.ToString());
Also try changing your font to a font that has both a Regular and Bold
appearance
For instance:
System.Drawing.Font f = new System.Drawing.Font("Tahoma", 10,
FontStyle.Regular);
chart1.ChartAreas["A"].AxisY.LabelStyle.Font = f;
I would recommend reorganize your code a little bit, which will allow you
to perform such operations easily using FindControl. Basically my
suggestion boils down to handling Command event not of the link button, but
of the repeater itself:
<asp:repeater
Then access to item contents is extremely easy:
protected void rpt_ItemCommand(object sender, RepeaterCommandEventArgs e)
{
Label label = e.Item.FindControl("lblMessage");
LinkButton linkButton = e.Item.FindControl("Delete");
}
This is working fine..
For Each rowItem In TaskDataGrid.ItemsSource
' Ensures that all rows are loaded.
TaskDataGrid.ScrollIntoView(rowItem,
TaskDataGrid.Columns.Last())
Dim fe As FrameworkElement =
TaskDataGrid.Columns(2).GetCellContent(rowItem)
Dim fe1 As FrameworkElement =
TaskDataGrid.Columns(1).GetCellContent(rowItem)
Dim gridCmbo As Grid = DirectCast(fe, Grid)
Dim gridCmbo1 As Grid = DirectCast(fe1, Grid)
Dim lbltaskId As Label = CType(gridCmbo1.FindName("lbltaskId"),
Label)
Dim lblBaseReceipt As Label =
CType(gridCmbo.FindName("lblBaseReceipt"), Label)
You may benefit from enabling double buffering, either at the label level
or possibly the form level.
There are examples of both here: winforms Label flickering.
I think you must have two instances of ModbusMaster.
One of them is the one you can see on the display, and is NOT being
updated.
The other one is the one you create in class Form1 with the line of code:
ModbusMaster mb = new ModbusMaster();
That is the one you are modifying, but it isn't the displayed one (I cannot
see anywhere that you can be displaying that).
What you need to do is use the reference to the actual displayed one
instead when you call mb.openPort("wooooo");
[EDIT]
Thinking about it - it's possible that you haven't instantiated another
user control at all.
Did you use Visual Studio's Form Designer to add the user control to your
main form? I had assumed that you did, but now I realise that might not be
the case.
If not, you should do that, give it the name mb and
Use asp:HyperLink control !
In your aspx ,
<asp:HyperLink
</asp:HyperLink>
In your cs ,
if(....yourCondition...)
{
yourHyperLink.Text = "YourText";
yourHyperLink.NavigateUrl = "YourURL";
}
I did my by...
Creating 2 forms.1 with the media player set to what ever size needed
The second form with...
formborderstyle = none
form2.left = form1.left + form1.mediaplayer.left
form2.top = form1.top + form1.mediaplayer.top
Lower the opacity to 70 or if you want it in code..
form2.opacity=0.7
Put your text or anything in the second form .
The final effect is a cool shade like effect with text in it with media
playing in the background.
If you are not married to the idea of using an HTTP Handler, then I suggest
making a method in your .aspx page's code-behind that does the same logic
your handler is doing minus the content-type stuff, like this:
protected string GetName(int pro_id)
{
return DBHelpername.name(pro_id);
}
Now in your markup you can use this method, like this:
<asp:Label ID="Label1" runat="server" Text='<%#
GetName((int)Eval("id")) %>'>
</asp:Label>
Try this out
<div class="ModalPopup" id="PopupDiv1">
<asp:UpdatePanel
<ContentTemplate>
<table>
<tr>
<td>
<div class="modalHeader">
<table width="100%">
<tr>
<td class="title">
<asp:Label</asp:Label>
</td>
<td>
It's not your code, it's a "feature" introduced in Windows Vista.
In Windows Vista, a Windows Shell programmer checked in a change (with no
spec/justification in the changelist) that changed the default label
control to copy its text to the clipboard when double-clicked.
This change typically doesn't impact C++ applications due to how they
create/host the label control, but it impacts all VS.NET applications. I
filed a bug against the (surprised) Framework team when I discovered this
in the Win7 timeframe, but they were scared to fix the bug because it had
been present for so long.
Here's the duplicate Is there any way to disable the "double-click to
copy" functionality of a .NET label?
Try chaning your code from this:
<asp:Label ID="lbl_category" runat="server" CssClass="<%#
Eval("CommentType") %>"
to this:
<asp:Label ID="lbl_category" runat="server" CssClass='<%#
Eval("CommentType") %>' />.;
}
}
The titleLabel property is primarily used to configure the text of the
button, not its bounds.
I don't think you can achieve what you want to achieve.
If I understand you correctly, you make a button with a small width and big
height in interface builder, then set the transformation on the label of
the button to 90º, and then expect the button to behave as if the width
became the height and vice versa.
I suppose you could still set the button in interface builder, but make it
horizontal, as if it's rotated -90º, and then set the transformation on
the UIButton in viewDidLoad
Try this
HTML
<label id="search">Advanced Search</label>
<div id="searchContent" style="display:none;">Something</div>
JavaScript
$(function () {
$("#search").click(function () {
var text = $(this).text();
if (text === "Advanced Search") {
$(this).text("Basic Search");
$("#searchContent").show();
} else {
$(this).text("Advanced Search");
$("#searchContent").hide();
}
});
});
Demo:.
I had the same issue and I get below response form Apple:
You need to update the constraints to match the frames of these views.
I did the following:
Editor -> Resolve Auto-Layout Issues -> Clear all constraints in ** view
controller
then I reordered my objects again in the view.
PS: Try Enrico's solution first.
You could write your css selector like this:
label[for=Username]
label[for=Live]
You may also have a look at this thread:
CSS Selector for selecting an element that comes BEFORE another element?
cowid is clearly null here so has not been initialized. stringWithFormat
shows this with the (null). You can have the confirmation by
if (detalles.Cowid == nil) {
NSLog(@"The Cow has no id");
}
ldr r0,=something
...
something:
means load the address of the label something into the register r0. The
assembler then adds a word somewhere in reach of the ldr instruction and
replaces it with a
ldr r0,[pc,#offset]
instruction
So this shortcut
ldr r0,=0x12345678
means load 0x12345678 into r0.
being mostly fixed length instructions, you cant load a full 32 bit
immediate into a register in one instruction, it can take a number of
instructions to completely load a register with a 32 bit number. Depends
heavily on the number. For example
ldr r0,=0x00010000
will get replaced by the gnu assembler with a single instruction mov
r0,#0x00010000 if it is an ARM instruction, for a thumb instruction though
it may still have to be ldr r0,[pc,#offset]
These ldr rd,=things are a shortc
Bootstrap seems to expect form controls within class="controls" elements.
It's a bit hacky but adding the following css rule should work
div.controls p {
margin-top:5px;
}
If this is your raw HTML:
<form action="">
<p>First Name</p>
<input type="text" name="fname" />
<p>Middle Name</p>
<input type="text" name="mname" />
<p>Last Name</p>
<input type="text" name="lname" />
<p>Age</p>
<input type="text" name="age" />
<p>Gender</p>
<select name="gender">
<option value="male">Male</option>
<option value="female">Female</option>
<p>Phone Number</p>
<input type="text" name="fname" />
</form>
You can use CSS to style the page.
Check out this link. It utilizes CSS to create 2 rows ('walls') with 6
columns ('panels') in each row.
If);
- | http://www.w3hello.com/questions/-ASP-label-control- | CC-MAIN-2018-17 | refinedweb | 1,593 | 55.34 |
Windows2Linux Porting
1. Who is the target reader of this article?
Recently I faced one very interesting task. I had to port an application from one platform (Windows) to another (Linux). It is an interesting topic. First, knowledge of several platforms and writing the code for them is a good experience for every developer. Secondly, writing an application for different platforms makes it widespread and needed by many. So, I would like to share my impressions concerning this process. This article is intended for everybody who wants to write a cross-platform application.
2. Our task
Receiving the project specification, we usually see only one target platform in the "Platforms" section (e.g., Windows) and that is why we enjoy its advantages and disadvantages. Let's imagine that you receive the task where it is proposed to run the application on the other platform (e.g., Linux). Or imagine that you have to use the code, which was written for one platform, on another platform. From this point you start to face difficulties. You start to plan the porting taking into account all the specifics of the program architecture. And if the architecture was wrong from the very beginning (I mean that it did not expect the porting between the platforms), it can turn out that you have to remake a lot. Let's examine the example of the code (file attached to this article). B This program opens the PhysicalDrive0, acquires MBR and writes it to the file, then defines the disk configuration and saves it to a separate file. The code was written only for Windows with all its consequences.
There must be no difficulties in such small example. But you can meet problems even here. The code is very simple and does not require many checks, deletion processing, etc. This code is not a standard but it lets to show what you should do during the porting of your application from Windows OS to Linux OS.
3. Compilers and IDE
When porting from Windows OS to Linux OS is performed, the porting from Microsoft Visual C++ to GCC(G++) is the most commonly used. Many of you may think that GCC and G++ are two different compilers. But it is not so. GCC (B+GNU C CompilerB;) was created in 1987 by Richard Stallman and it could compile only C code at that time. With time the compiler developed and supported not only C and C++ codes but also other programming languages. Now the GCC is interpreted as B+GNU Compiler CollectionB;. G++ is a part of GCC and is used to compile *.cpp files. GCC is used, in its turn, to compile *.Q files. Though, you can compile the *.cpp file using GCC by indicating specific flags. GCC and G++ compile the C++ code in the same way.
Let's return to the porting from Visual C++ to GCC (G++). It is worth paying attention to the difference between them. GCC is stricter to the standard than the Microsoft compiler. It means that in some situation the GCC compiler returns an error message and does not compile the source code while the Microsoft compiler just returns the warning message. Let's examine some moments that are frequently met during the porting from Visual C++ to GCC. You can google it but I would like to repeat it myself.
- Use #ifndef/#define/#endif instead of #pragma once. GCC understands the #pragma once directive beginning from the version 3.4. That is why check the version of your compiler. If it is lower than 3.4, there is no need to correct the following code during the porting.
#ifndef SOME_HEADER_H #define SOME_HEADER_H // code. #endif // SOME_HEADER_H
- Used types. During the porting, watch the types you use because GCC doesn't understand all of them. It is better to create a separate file in the project (e.g., types.h file) and to put there all types that GCC does not understand.
HANDLE //typedef void * HANDLE; in winnt.h DWORD //typedef unsigned long DWORD; in WinDef.h BYTE //typedef unsigned char BYTE; in WinDef.h UINT //typedef unsigned int UINT; in WinDef.h
- Assembler insertions. Be careful during the porting of ASM insertions to the project for GCC. They have another appearance and syntax. GCC uses AT&T ASM. It differs from Intel ASM, which is used in Visual C++. An example is provided below (the following example is taken from; for more information about AT&T ASM also see this reference).
B B B B B B B B B
P.S. For conversion, you can use the Intel2gas utility (see). But to my opinion, it is more convenient only for the high volume of the ASM code. And anyway you should bring the code to the compilable state. B
- Using the #pragma comment directive (lib, "libname.lib"). It is convenient to hook libraries in the project with the help of this directive in Visual C++. But GCC does not contain such one. That is why, for GCC, you should define the libraries you want to hook in the command line. For example:
g++ -o TestExe.exe *.o -Llib -lm -ldl -w "lib_1.a" "lib_2.a" "lib_3.a"
As you can see, Linux libraries have *.a extension and not *.lib extension as in Windows OS. Dynamic libraries also have another extension (*.so instead of *.dll) and they link not in such way as in Windows OS. For more information about the types of libraries in Linux OS see.
- Macros. Macros in GCC differ from the analogous ones in Visual C++. During the code porting to GP!P!, check the macros in the code. It's possible that the implementation of such macro will not be performed. In such situation, it is better to find its implementation in Visual P!++ and port it to GCC. The following table provides examples of frequently used macros.
__DATE__ __DATE__ __FILE__ __FILE__ __LINE__ __LINE__ __STDC__ __STDC__ __TIME__ __TIME__ __TIMESTAMP__ __TIMESTAMP__ __FUNCTION__ __FUNCTION__ __PRETTY_FUNCTION__ MSC_VER __GNUC__ __GNUC_MINOR__ __GNUC_PATCHLEVEL__
Let's examine them. The first six macros are implemented in both compilers in the same way and are often used in logging. The differences begin from __FUNCTION__. In Windows OS, it writes not only the name of the function (as in Linux OS) but also the namespace and the class from where the call was performed. Its analog in Linux OS is not __FUNCTION__ but __PRETTY_FUNCTION__. MSC_VER and __GNUC__ / __GNUC_MINOR__ / __GNUC_PATCHLEVEL__ also have different types of returned data. For example, MSC_VER = 1500 for Visual C++, for GNU 3.2.2 it is __GNUC__ = 3, __GNUC_MINOR__ = 2, __GNUC_PATCHLEVEL__ = 2.
If the target platform does not include the needed macro, find its implementation and port it. Macro can be also written in ASM (for the code optimization). Do not hurry and rewrite it from Intel to AT&T and vice versa. It is better to check once more if there is its implementation in P!++. Also take into account that Linux OS can run on devices with ARM processor. In this case the macro, which was written under AT&T, will not work and you will have to implement it under another type of the processor.
Let's move to IDE. There are lots of them and you have the possibility to choose. Let's examine some of them (taking into account that the project was initially written in Visual Studio, our task is to choose IDE for working in Linux OS):
- Code::Blocks (see)
Pic.1 Code::Blocks. Start Page.
It is often proposed as the substitution of Visual Studio for those who port their project to Linux OS. IDE can open Visual Studio projects under Windows OS and Linux OS. I built a project with its help and I can say that it is very convenient. | https://www.codeguru.com/cpp/w-p/article.php/c17231/Windows2Linux-Porting.htm | CC-MAIN-2019-35 | refinedweb | 1,300 | 67.65 |
Singly Linked Lists in C++
In a recent post I wrote about removing items from a singly linked list. I presented a couple of alternative implementations, and in the comments section readers suggested yet more versions.
My implementations were written in C: the post was inspired by something Linus Torvalds had said about low-level programming skills, and I’m guessing he meant C programming skills. The fact is, C programmers are condemned to reimplement these basic functions on this basic structure because the C standard library has nothing to say about singly linked lists. Until recently the C++ standard library was similarly silent on the subject, only offering a doubly linked list.
C++ introduces … the linked list!
That’s all changed now with the introduction of
std::forward_list. The class interface doesn’t mention links or pointers but a quick glance through its contents makes it clear that if you imagine the container to be a templated version of a classic singly-linked list, you won’t go far wrong.
This gives
forward_list some members you won’t find elsewhere in the
std:: namespace. For example,
std::forward_list::before_begin(), which returns an iterator just before the beginning of the list — much as the more familiar
end() is just past the end.
Why is
before_begin() necessary? You can’t dereference it and you can’t reverse through a forward list till you get to it. Well, since forward list iterators can only go forwards, instead of the familiar sequence
insert(),
erase() and
emplace() methods we have
insert_after(),
erase_after() and
emplace_after(), not to mention
splice_after(). The before-the-beginning iterator allows you to use these operations to modify the node at the head of the list.
Quick question: what’s the complexity of
std::list::size()?
Trick question: and how about
std::forward_list::size()?
Remove_if for forward lists
Using pointers-to-pointers to modify linked lists gives this elegant and compact C implementation of
remove_if(), which de-lists all nodes which match a supplied predicate.
void remove_if(node ** head, remove_fn rm) { for (node** curr = head; *curr; ) { node * entry = *curr; if (rm(entry)) { *curr = entry->next; free(entry); } else curr = &entry->next; } }
How does the C++ standard library support this algorithm?
Std::remove_if() operates on an iterator range,
remove_if(first, last, pred). All it requires is that the iterators are forward iterators so it should just work on a
forward_list.
Hang on though: what if
pred(*first) is true? How can a node be removed from a linked list without reference to its predecessor? Actually, the node isn’t removed — the value it contains gets overwritten by the value in the first node (if any!) for which the predicate returns false. In fact,
remove_if doesn’t remove anything from the container! What it does is return an iterator, call it
new_last, such that the range
(first, new_last) holds the elements which have been kept, and
(new_last, last) holds those which have been “removed”, which is to say they can still be dereferenced but their value is implementation dependent.
Remove_if usually pairs up with erase:
container.erase(remove_if(first, last, pred), last);
There is no
std::forward_list::erase(iterator) — remember, we can only erase after — so the usual remove_if algorithm is of little use for forward lists.
Forward_list::remove_if()
As usual, we should prefer member functions to algorithms with the same names. C++’s
forward_list has its very own
remove_if which manipulates pointers rather than moves values, and which really does remove and destroy items.
Forward_list::remove_if() operates on the list as a whole, not an iterator range — as we’ve seen, an iterator cannot remove itself. I took a look at a couple of implementations of this function to see how it’s done.
Here’s LLVM’s libc++ implementation:
template <class _Tp, class _Alloc> template <class _Predicate> void forward_list<_Tp, _Alloc>::remove_if(_Predicate __pred) { iterator __e = end(); for (iterator __i = before_begin(); __i.__ptr_->__next_ != nullptr;) { if (__pred(__i.__ptr_->__next_->__value_)) { iterator __j = _VSTD::next(__i, 2); for (; __j != __e && __pred(*__j); ++__j) ; erase_after(__i, __j); if (__j == __e) break; __i = __j; } else ++__i; } }
There’s no need for any special treatment of the first list node here, since we have its predecessor, the
before_begin() node. The function does double back though, figuring out the next range to erase before going back to erase it — and the erase function isn’t pretty.
template <class _Tp, class _Alloc> typename forward_list<_Tp, _Alloc>::iterator forward_list<_Tp, _Alloc>::erase_after(const_iterator __f, const_iterator __l) { __node_pointer __e = const_cast<__node_pointer>(__l.__ptr_); if (__f != __l) { __node_pointer __p = const_cast<__node_pointer>(__f.__ptr_); __node_pointer __n = __p->__next_; if (__n != __e) { __p->__next_ = __e; __node_allocator& __a = base::__alloc(); do { __p = __n->__next_; __node_traits::destroy(__a, _VSTD::addressof(__n->__value_)); __node_traits::deallocate(__a, __n, 1); __n = __p; } while (__n != __e); } } return iterator(__e); }
For comparison, here’s how GCC’s libstdc++ does the same thing.
template<typename _Tp, typename _Alloc> template<typename _Pred> void forward_list<_Tp, _Alloc>:: remove_if(_Pred __pred) { _Node* __curr = static_cast<_Node*>(&this->_M_impl._M_head); while (_Node* __tmp = static_cast<_Node*>(__curr->_M_next)) { if (__pred(*__tmp->_M_valptr())) this->_M_erase_after(__curr); else __curr = static_cast<_Node*>(__curr->_M_next); } }
Here, erasing (after a) node reads:
template<typename _Tp, typename _Alloc> _Fwd_list_node_base* _Fwd_list_base<_Tp, _Alloc>:: _M_erase_after(_Fwd_list_node_base* __pos) { _Node* __curr = static_cast<_Node*>(__pos->_M_next); __pos->_M_next = __curr->_M_next; _Tp_alloc_type __a(_M_get_Node_allocator()); allocator_traits<_Tp_alloc_type>::destroy(__a, __curr->_M_valptr()); __curr->~_Node(); _M_put_node(__curr); return __pos->_M_next; }
This version walks through the list removing nodes which match the predicate as it finds them. Don’t be confused by
&this->_M_impl._M_head: it’s not the node at the head of the list, it’s the one before.
Lessons from C++
Maybe this code wouldn’t persaude Linus Torvalds to rethink his opinion of C++, but if you can see past the angle brackets, underscores and allocators, it’s simple enough.
It’s also:
- subtle, so I’m glad someone else has written and checked it
- generic, so I can put what I want in a list without casting or indirection
- standard, so I know what to expect
- supported
The before-begin node idea serves equally well in C, enabling list modifiers which have no need of double indirection or special case code for the list head.
void remove_after(node * prev, remove_fn rm) { while (prev->next != NULL) { node * curr = prev->next; if (rm(curr)) { prev->next = curr->next; free(curr); } else prev = curr; } }
Pass this function the before-begin node to remove all items from the list which match the predicate. | http://wordaligned.org/articles/singly-linked-lists-in-c++ | CC-MAIN-2016-50 | refinedweb | 1,083 | 52.7 |
Jesse Li·Friday, January 17 2020·Improve this Guide
Learn everything you need to know about BitTorrent by writing a client in Go
BitTorrent is a protocol for downloading and distributing files across the Internet. In contrast with the traditional client/server relationship, in which downloaders connect to a central server (for example: watching a movie on Netflix, or loading the web page you're reading now), participants in the BitTorrent network, called peers, download pieces of files from each other—this is what makes it a peer-to-peer protocol. In this article we will investigate how this works, and build our own client that can find peers and exchange data between them.
The protocol evolved organically over the past 20 years, and various people and organizations added extensions for features like encryption, private torrents, and new ways of finding peers. We'll be implementing the original spec from 2001 to keep this a weekend-sized project.
I'll be using a Debian ISO file as my guinea pig because it's big, but not huge, at 350MB. As a popular Linux distribution, there will be lots of fast and cooperative peers for us to connect to. And we'll avoid the legal and ethical issues related to downloading pirated content.
Here’s a problem: we want to download a file with BitTorrent, but it’s a peer-to-peer protocol and we have no idea where to find peers to download it from. This is a lot like moving to a new city and trying to make friends—maybe we’ll hit up a local pub or a meetup group! Centralized locations like these are the big idea behind trackers, which are central servers that introduce peers to each other. They’re just web servers running over HTTP, and you can find Debian’s at
Of course, these central servers are liable to get raided by the feds if they facilitate peers exchanging illegal content. You may remember reading about trackers like TorrentSpy, Popcorn Time, and KickassTorrents getting seized and shut down. New methods cut out the middleman by making even peer discovery a distributed process. We won't be implementing them, but if you're interested, some terms you can research are DHT, PEX, and magnet links.
A .torrent file describes the contents of a torrentable file and information for connecting to a tracker. It's all we need in order to kickstart the process of downloading a torrent. Debian's .torrent file looks like this:
d8:announce41::"Debian CD from cdimage.debian.org"13:creation datei1573903810e9:httpseedsl145: lengthi262144e6:pieces26800:�����PS�^�� (binary blob of the hashes of each piece)ee
That mess is encoded in a format called Bencode (pronounced bee-encode), and we'll need to decode it.
Bencode can encode roughly the same types of structures as JSON—strings, integers, lists, and dictionaries. Bencoded data is not as human-readable/writable as JSON, but it can efficiently handle binary data and it's really simple to parse from a stream. Strings come with a length prefix, and look like
4:spam. Integers go between start and end markers, so
7 would encode to
i7e. Lists and dictionaries work in a similar way:
l4:spami7ee represents
['spam', 7], while
d4:spami7ee means
{spam: 7}.
In a prettier format, our .torrent file looks like this:
d 8:announce 41: 7:comment 35:"Debian CD from cdimage.debian.org" 13:creation date i1573903810e 4:info d 6:length i351272960e 4:name 31:debian-10.2.0-amd64-netinst.iso 12:piece length i262144e 6:pieces 26800:�����PS�^�� (binary blob of the hashes of each piece) e e
In this file, we can spot the URL of the tracker, the creation date (as a Unix timestamp), the name and size of the file, and a big binary blob containing the SHA-1 hashes of each piece, which are equally-sized parts of the file we want to download. The exact size of a piece varies between torrents, but they are usually somewhere between 256KB and 1MB. This means that a large file might be made up of thousands of pieces. We'll download these pieces from our peers, check them against the hashes from our torrent file, assemble them together, and boom, we've got a file!
This mechanism allows us to verify the integrity of each piece as we go. It makes BitTorrent resistant to accidental corruption or intentional torrent poisoning. Unless an attacker is capable of breaking SHA-1 with a preimage attack, we will get exactly the content we asked for.
It would be really fun to write a bencode parser, but parsing isn't our focus today. But I found Fredrik Lundh's 50 line parser to be especially illuminating. For this project, I used github.com/jackpal/bencode-go:
import ( "github.com/jackpal/bencode-go" ) type bencodeInfo struct { Pieces string `bencode:"pieces"` PieceLength int `bencode:"piece length"` Length int `bencode:"length"` Name string `bencode:"name"` } type bencodeTorrent struct { Announce string `bencode:"announce"` Info bencodeInfo `bencode:"info"` } // Open parses a torrent file func Open(r io.Reader) (*bencodeTorrent, error) { bto := bencodeTorrent{} err := bencode.Unmarshal(r, &bto) if err != nil { return nil, err } return &bto, nil }
Because I like to keep my structures relatively flat, and I like to keep my application structs separate from my serialization structs, I exported a different, flatter struct named
TorrentFile and wrote a few helper functions to convert between the two.
Notably, I split
pieces (previously a string) into a slice of hashes (each
[20]byte) so that I can easily access individual hashes later. I also computed the SHA-1 hash of the entire bencoded
info dict (the one which contained the name, size, and piece hashes). We know this as the infohash and it uniquely identifies files when we talk to trackers and peers. More on this later.
type TorrentFile struct { Announce string InfoHash [20]byte PieceHashes [][20]byte PieceLength int Length int Name string } func (bto *bencodeTorrent) toTorrentFile() (*TorrentFile, error) { // ... }
Now that we have information about the file and its tracker, let's talk to the tracker to announce our presence as a peer and to retrieve a list of other peers. We just need to make a GET request to the
announce URL supplied in the .torrent file, with a few query parameters:
func (t *TorrentFile) buildTrackerURL(peerID [20]byte, port uint16) (string, error) { base, err := url.Parse(t.Announce) if err != nil { return "", err } params := url.Values{ "info_hash": []string{string(t.InfoHash[:])}, "peer_id": []string{string(peerID[:])}, "port": []string{strconv.Itoa(int(Port))}, "uploaded": []string{"0"}, "downloaded": []string{"0"}, "compact": []string{"1"}, "left": []string{strconv.Itoa(t.Length)}, } base.RawQuery = params.Encode() return base.String(), nil }
The important ones:
infodict. The tracker will use this to figure out which peers to show us.
-TR2940-k8hj0wgej6chwhich identify the client software and version—in this case, TR2940 stands for Transmission client 2.94.
We get back a bencoded response:
d 8:interval i900e 5:peers 252:(another long binary blob) e
Interval tells us how often we're supposed to connect to the tracker again to refresh our list of peers. A value of 900 means we should reconnect every 15 minutes (900 seconds).
Peers is another long binary blob containing the IP addresses of each peer. It's made out of groups of six bytes. The first four bytes in each group represent the peer's IP address—each byte represents a number in the IP. The last two bytes represent the port, as a big-endian
uint16. Big-endian, or network order, means that we can interpret a group of bytes as an integer by just squishing them together left to right. For example, the bytes
0x1A,
0xE1 make
0x1AE1, or 6881 in decimal.
// Peer encodes connection information for a peer type Peer struct { IP net.IP Port uint16 } // Unmarshal parses peer IP addresses and ports from a buffer func Unmarshal(peersBin []byte) ([]Peer, error) { const peerSize = 6 // 4 for IP, 2 for port numPeers := len(peersBin) / peerSize if len(peersBin)%peerSize != 0 { err := fmt.Errorf("Received malformed peers") return nil, err } peers := make([]Peer, numPeers) for i := 0; i < numPeers; i++ { offset := i * peerSize peers[i].IP = net.IP(peersBin[offset : offset+4]) peers[i].Port = binary.BigEndian.Uint16(peersBin[offset+4 : offset+6]) } return peers, nil }
Now that we have a list of peers, it's time to connect with them and start downloading pieces! We can break down the process into a few steps. For each peer, we want to:
conn, err := net.DialTimeout("tcp", peer.String(), 3*time.Second) if err != nil { return nil, err }
I set a timeout so that I don't waste too much time on peers that aren't going to let me connect. For the most part, it's a pretty standard TCP connection.
We've just set up a connection with a peer, but we want do a handshake to validate our assumptions that the peer
My father told me that the secret to a good handshake is a firm grip and eye contact. The secret to a good BitTorrent handshake is that it's made up of five parts:
BitTorrent protocol
Put together, a handshake string might look like this:
\x13BitTorrent protocol\x00\x00\x00\x00\x00\x00\x00\x00\x86\xd4\xc8\x00\x24\xa4\x69\xbe\x4c\x50\xbc\x5a\x10\x2c\xf7\x17\x80\x31\x00\x74-TR2940-k8hj0wgej6ch
After we send a handshake to our peer, we should receive a handshake back in the same format. The infohash we get back should match the one we sent so that we know that we're talking about the same file. If everything goes as planned, we're good to go. If not, we can sever the connection because there's something wrong. "Hello?" "这是谁？ 你想要什么？" "Okay, wow, wrong number."
In our code, let's make a struct to represent a handshake, and write a few methods for serializing and reading them:
// A Handshake is a special message that a peer uses to identify itself type Handshake struct { Pstr string InfoHash [20]byte PeerID [20]byte } // Serialize serializes the handshake to a buffer func (h *Handshake) Serialize() []byte { buf := make([]byte, len(h.Pstr)+49) buf[0] = byte(len(h.Pstr)) curr := 1 curr += copy(buf[curr:], h.Pstr) curr += copy(buf[curr:], make([]byte, 8)) // 8 reserved bytes curr += copy(buf[curr:], h.InfoHash[:]) curr += copy(buf[curr:], h.PeerID[:]) return buf } // Read parses a handshake from a stream func Read(r io.Reader) (*Handshake, error) { // Do Serialize(), but backwards // ... }
Once we've completed the initial handshake, we can send and receive messages. Well, not quite—if the other peer isn't ready to accept messages, we can't send any until they tell us they're ready. In this state, we're considered choked by the other peer. They'll send us an unchoke message to let us know that we can begin asking them for data. By default, we assume that we're choked until proven otherwise.
Once we've been unchoked, we can then begin sending requests for pieces, and they can send us messages back containing pieces.
A message has a length, an ID and a payload. On the wire, it looks like:
A message starts with a length indicator which tells us how many bytes long the message will be. It's a 32-bit integer, meaning it's made out of four bytes smooshed together in big-endian order. The next byte, the ID, tells us which type of message we're receiving—for example, a
2 byte means "interested." Finally, the optional payload fills out the remaining length of the message.
type messageID uint8 const ( MsgChoke messageID = 0 MsgUnchoke messageID = 1 MsgInterested messageID = 2 MsgNotInterested messageID = 3 MsgHave messageID = 4 MsgBitfield messageID = 5 MsgRequest messageID = 6 MsgPiece messageID = 7 MsgCancel messageID = 8 ) // Message stores ID and payload of a message type Message struct { ID messageID Payload []byte } // Serialize serializes a message into a buffer of the form // <length prefix><message ID><payload> // Interprets `nil` as a keep-alive message func (m *Message) Serialize() []byte { if m == nil { return make([]byte, 4) } length := uint32(len(m.Payload) + 1) // +1 for id buf := make([]byte, 4+length) binary.BigEndian.PutUint32(buf[0:4], length) buf[4] = byte(m.ID) copy(buf[5:], m.Payload) return buf }
To read a message from a stream, we just follow the format of a message. We read four bytes and interpret them as a
uint32 to get the length of the message. Then, we read that number of bytes to get the ID (the first byte) and the payload (the remaining bytes).
// Read parses a message from a stream. Returns `nil` on keep-alive message func Read(r io.Reader) (*Message, error) { lengthBuf := make([]byte, 4) _, err := io.ReadFull(r, lengthBuf) if err != nil { return nil, err } length := binary.BigEndian.Uint32(lengthBuf) // keep-alive message if length == 0 { return nil, nil } messageBuf := make([]byte, length) _, err = io.ReadFull(r, messageBuf) if err != nil { return nil, err } m := Message{ ID: messageID(messageBuf[0]), Payload: messageBuf[1:], } return &m, nil }
One of the most interesting types of message is the bitfield, which is a data structure that peers use to efficiently encode which pieces they are able to send us. A bitfield looks like a byte array, and to check which pieces they have, we just need to look at the positions of the bits set to 1. You can think of it like the digital equivalent of a coffee shop loyalty card. We start with a blank card of all
0, and flip bits to
1 to mark their positions as "stamped."
By working with bits instead of bytes, this data structure is super compact. We can stuff information about eight pieces in the space of a single byte—the size of a
bool. The tradeoff is that accessing values becomes a little more tricky. The smallest unit of memory that computers can address are bytes, so to get to our bits, we have to do some bitwise manipulation:
// A Bitfield represents the pieces that a peer has type Bitfield []byte // HasPiece tells if a bitfield has a particular index set func (bf Bitfield) HasPiece(index int) bool { byteIndex := index / 8 offset := index % 8 return bf[byteIndex]>>(7-offset)&1 != 0 } // SetPiece sets a bit in the bitfield func (bf Bitfield) SetPiece(index int) { byteIndex := index / 8 offset := index % 8 bf[byteIndex] |= 1 << (7 - offset) }
We now have all the tools we need to download a torrent: we have a list of peers obtained from the tracker, and we can communicate with them by dialing a TCP connection, initiating a handshake, and sending and receiving messages. Our last big problems are handling the concurrency involved in talking to multiple peers at once, and managing the state of our peers as we interact with them. These are both classically Hard problems.
In Go, we share memory by communicating, and we can think of a Go channel as a cheap thread-safe queue.
We'll set up two channels to synchronize our concurrent workers: one for dishing out work (pieces to download) between peers, and another for collecting downloaded pieces. As downloaded pieces come in through the results channel, we can copy them into a buffer to start assembling our complete file.
// Init queues for workers to retrieve work and send results workQueue := make(chan *pieceWork, len(t.PieceHashes)) results := make(chan *pieceResult) for index, hash := range t.PieceHashes { length := t.calculatePieceSize(index) workQueue <- &pieceWork{index, hash, length} } // Start workers for _, peer := range t.Peers { go t.startDownloadWorker(peer, workQueue, results) } // Collect results into a buffer until full buf := make([]byte, t.Length) donePieces := 0 for donePieces < len(t.PieceHashes) { res := <-results begin, end := t.calculateBoundsForPiece(res.index) copy(buf[begin:end], res.buf) donePieces++ } close(workQueue)
We'll spawn a worker goroutine for each peer we've received from the tracker. It'll connect and handshake with the peer, and then start retrieving work from the
workQueue, attempting to download it, and sending downloaded pieces back through the
results channel.
func (t *Torrent) startDownloadWorker(peer peers.Peer, workQueue chan *pieceWork, results chan *pieceResult) { c, err := client.New(peer, t.PeerID, t.InfoHash) if err != nil { log.Printf("Could not handshake with %s. Disconnecting\n", peer.IP) return } defer c.Conn.Close() log.Printf("Completed handshake with %s\n", peer.IP) c.SendUnchoke() c.SendInterested() for pw := range workQueue { if !c.Bitfield.HasPiece(pw.index) { workQueue <- pw // Put piece back on the queue continue } // Download the piece buf, err := attemptDownloadPiece(c, pw) if err != nil { log.Println("Exiting", err) workQueue <- pw // Put piece back on the queue return } err = checkIntegrity(pw, buf) if err != nil { log.Printf("Piece #%d failed integrity check\n", pw.index) workQueue <- pw // Put piece back on the queue continue } c.SendHave(pw.index) results <- &pieceResult{pw.index, buf} } }
We'll keep track of each peer in a struct, and modify that struct as we read messages. It'll include data like how much we've downloaded from the peer, how much we've requested from them, and whether we're choked. If we wanted to scale this further, we could formalize this as a finite state machine. But a struct and a switch are good enough for now.
type pieceProgress struct { index int client *client.Client buf []byte downloaded int requested int backlog int } func (state *pieceProgress) readMessage() error { msg, err := state.client.Read() // this call blocks switch msg.ID { case message.MsgUnchoke: state.client.Choked = false case message.MsgChoke: state.client.Choked = true case message.MsgHave: index, err := message.ParseHave(msg) state.client.Bitfield.SetPiece(index) case message.MsgPiece: n, err := message.ParsePiece(state.index, state.buf, msg) state.downloaded += n state.backlog-- } return nil }
Files, pieces, and piece hashes aren't the full story—we can go further by breaking down pieces into blocks. A block is a part of a piece, and we can fully define a block by the index of the piece it's part of, its byte offset within the piece, and its length. When we make requests for data from peers, we are actually requesting blocks. A block is usually 16KB large, meaning that a single 256 KB piece might actually require 16 requests.
A peer is supposed to sever the connection if they receive a request for a block larger than 16KB. However, based on my experience, they're often perfectly happy to satisfy requests up to 128KB. I only got moderate gains in overall speed with larger block sizes, so it's probably better to stick with the spec.
Network round-trips are expensive, and requesting each block one by one will absolutely tank the performance of our download. Therefore, it's important to pipeline our requests such that we keep up a constant pressure of some number of unfulfilled requests. This can increase the throughput of our connection by an order of magnitude.
Classically, BitTorrent clients kept a queue of five pipelined requests, and that's the value I'll be using. I found that increasing it can up to double the speed of a download. Newer clients use an adaptive queue size to better accommodate modern network speeds and conditions. This is definitely a parameter worth tweaking, and it's pretty low hanging fruit for future performance optimization.
// MaxBlockSize is the largest number of bytes a request can ask for const MaxBlockSize = 16384 // MaxBacklog is the number of unfulfilled requests a client can have in its pipeline const MaxBacklog = 5 func attemptDownloadPiece(c *client.Client, pw *pieceWork) ([]byte, error) { state := pieceProgress{ index: pw.index, client: c, buf: make([]byte, pw.length), } // Setting a deadline helps get unresponsive peers unstuck. // 30 seconds is more than enough time to download a 262 KB piece c.Conn.SetDeadline(time.Now().Add(30 * time.Second)) defer c.Conn.SetDeadline(time.Time{}) // Disable the deadline for state.downloaded < pw.length { // If unchoked, send requests until we have enough unfulfilled requests if !state.client.Choked { for state.backlog < MaxBacklog && state.requested < pw.length { blockSize := MaxBlockSize // Last block might be shorter than the typical block if pw.length-state.requested < blockSize { blockSize = pw.length - state.requested } err := c.SendRequest(pw.index, state.requested, blockSize) if err != nil { return nil, err } state.backlog++ state.requested += blockSize } } err := state.readMessage() if err != nil { return nil, err } } return state.buf, nil }
This is a short one. We're almost there.
package main import ( "log" "os" "github.com/veggiedefender/torrent-client/torrentfile" ) func main() { inPath := os.Args[1] outPath := os.Args[2] tf, err := torrentfile.Open(inPath) if err != nil { log.Fatal(err) } err = tf.DownloadToFile(outPath) if err != nil { log.Fatal(err) } }
For brevity, I included only a few of the important snippets of code. Notably, I left out all the glue code, parsing, unit tests, and the boring parts that build character. View my full implementation if you're interested.
Community created roadmaps, articles, resources and journeys to help you choose your path and grow in your career.
© roadmap.sh · FAQ · Terms · Privacy | https://roadmap.sh/guides/torrent-client | CC-MAIN-2021-17 | refinedweb | 3,529 | 65.32 |
Extending the Windows Explorer with Name Space Extensions
David Campbell
David Campbell is a Support Engineer on the Microsoft Premier Developer Support team who specializes in Windows shell extensions as well as Microsoft Visual C++. He also likes cheese.
Windows¨95 and Windows NT¨ 4.0 contain a mechanism that allows information to be integrated into the internal hierarchical data structures of the Windows Explorer. This hierarchical data, the "name space," contains information about objects displayed in the Explorer's panes. A name space is a collection of symbols, such as database keys or file and directory names.
The Windows 95 shell uses a single hierarchical name space to organize all objects such as files, storage devices, printers, network resources, and anything else that can be viewed using Explorer. The root of this unified name space is the Windows 95 desktop. While similar to a file system's directory structure, the name space contains more types of objects than just files and directories.
OK, but why do I care? This name space mechanism can be extended to include new items. You can write a name space extension to add your own custom data, and custom views on that data, into the Explorer's internal name space. With a freshly installed Windows 95 or Windows NT 4.0, a standard name space is part of the product. This name space includes the standard components you see with a clean install of Windows. There is code in the operating systems that interact with Explorer to represent the standard name space. Therefore, your name space extension is additional code that allows Explorer to represent your additional name space data.
Since the name space extension mechanism is based on COM, I will assume you are familiar with COM. You should also be familiar with writing shell extensions. If not, read Jeff Prosise's article "Integrate Your Applications with the Windows 95 User Interface Using Shell Extensions" in the March 1995 issue of MSJ.
Note that the information presented here is subject to change and is based on the Cab File Viewer sample recently released by Microsoft. The Cab File Viewer was released as part of the Power Toys collection of applications and extensions to enhance Windows 95. Download the Power Toys collection from. The Cab File Viewer extends the name space to allow Explorer to browse into CABinet files. These are compressed archive files, similar to ZIP files, that Microsoft uses to distribute software, including Windows 95. The Cab File Viewer name space extension provides code that Explorer can use to display CAB file contents. You can get source for the Cab File Viewer along with preliminary documentation on Explorer's name space mechanism from. To build a name space extension, you will also need an updated version of ShlObj.H, which is included in the Cab File Viewer sample source and should also be in the next release of the Win32¨ SDK.
The name space is a very large topic, and even the subset implemented in the Cab File Viewer is too large to be adequately covered in this article. Rather than walk you painfully through the code, I will instead cover information on the name space mechanism itself to allow you to understand the basics of name space extensions. You'll then be able to review the sample code on your own along with the new header files, and explore some of the more advanced topics, including the ability to generate per item context menus, icon handlers, and support for drag and drop.
Windows 95 and Windows NT 4.0 use a data structure-the name space-that represents the hierarchy of objects all the way from the desktop to every item that can be seen in Explorer. From the desktop you can view Network Neighborhood, My Briefcase, Recycle Bin, and My Computer. From My Computer you can get to drives, Control Panel, Printers, and Dial-Up Networking. Look at the left pane of Explorer to see the hierarchy of objects clearly. These items are called virtual folders-virtual because they refer to items in the name space that can contain other name space items, as opposed to groups of files.
Explorer uses COM interfaces to let the user access and manipulate internal name space data and to display it in a graphical form. In the COM paradigm, you are supposed to manipulate and extend the internal name space structures using COM interfaces instead of directly accessing the name space data.
You may have already noticed that the EnumDesk sample from the MSDN CD and the Windows Explorer look almost exactly the same. This is because both Explorer and EnumDesk walk though the name space and display the information in the name space. Both Explorer and EnumDesk call into the name space to enumerate the contents of a folder. They can then step through the items in the folder and call another interface to find out what to display. I will go through these steps in more detail later in this article.
There are two high-level topics to discuss on name space extensions before I jump into the details: rooted versus nonrooted name space extensions and the point of entry.
The difference between rooted extensions and nonrooted extensions is how they're used. There is no code difference between the two. A rooted extension is meant to stand alone. Essentially, the extension is the root of the tree and can only see its own branches. To see an example of a rooted extension, right-click on the Windows 95 taskbar, choose Properties, click the Start Menu Programs tab, and click the Advanced button. You will see an Explorer-like window with the Start Menu folder as the root, as in Figure 1. In the case of the Cab File Viewer (see Figure 2), it is also a rooted extension, since the window shown does not let you step backwards to the CAB file.
Figure 1 Rooted name space
Figure 2 CAB File Viewer
A nonrooted use of a name space extension keeps the entire name space in mind. Right click on the Windows 95 Start button on the taskbar and select Explore from the pop-up menu. In this case, the exact same name space extension is shown in an Explorer window (see Figure 3), except you can step back from the Start Menu folder and traipse around the rest of the name space.
Figure 3 Nonrooted name space
The implementation of the name space extension is basically the same for both kinds. Which method you use depends on your extension and is a matter of style and common sense as much as anything else.
Now let's talk about entry points. The root, or top level, of your name space is referred to as the junction point. In the case of the Cab File Viewer, the junction point is the CAB file itself. There is a restriction in the current Explorer-any name space that is implemented with a file (like CAB) as its junction point must be rooted, since the Explorer does not support exploring directly into files.
An alternative is to use a directory as the junction point. To do this, you must create a directory, change the directory's attributes to read-only, and place a file called Desktop.ini into it. This INI file then specifies the CLSID of your extension:
[.ShellClassInfo]
CLSID={CLSID}
This file basically replaces the CAB entry in the registry.
Yet another alternative is to use the CLSID of your name space extension as the file extension of a folder. If you wanted to create a folder called Cheese that was really the junction point of a name space extension, you would actually create a folder named "Cheese.{CLSID}".
Another difference between name space implementations is the actual "entry point" from the user's point of view. The user can enter via an icon like the Recycle Bin on the desktop or in the My Computer folder, for example. Or the entry point can be a file type (or directory) that is registered to your extension, like the Cab File Viewer.
You can place an entry point on the desktop or in the My Computer folder in several ways. First, you can put information in the registry that results in an icon being placed on the desktop, the icon coming from the CLSID in this registry entry:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\
Explorer\Desktop\Namespace\{CLSID}\(default) =
"Description of my extension"
This is what you'd use to place the icon in the My Computer folder:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\
Explorer\MyComputer\Namespace\{CLSID}\(default) =
"Description of my extension"
So should you implement a rooted or nonrooted extension? And should the entry point be on the desktop or somewhere else? It depends on your extension. Does your extension fit into the logical hierarchy of the name space? Does it make sense to move up a level in the hierarchy from your name space? If not, a rooted extension may make more sense.
Suppose you are implementing an extension to browse Usenet newsgroups. Does it make sense to have more than one entry point? Not really, so an entry point on the desktop seems reasonable. What about rooting? You could argue either way, but I would think that it should be rooted. What if you wanted to browse into a database file of some sort? Well, since it's reasonable for more than one to exist on your machine, it makes sense to use the location of the file itself as the entry point. As for rooting, if you use the file as the junction point, a rooted extension is your only option.
Like all shell extensions, a name space extension is registered in the Windows registry so that Explorer can determine its location and what services are available.
Here's the basic layout and options for the registry. First, if you are registering a file type to be treated like a name space extension, you need:
HKEY_CLASSES_ROOT\.EXT\(default)=CLSID\{CLSID} ;
This is only necessary if you are registering an extension for a specific file.
The rest is similar to other shell extensions,
HKEY_CLASSES_ROOT\CLSID\{0CD7A5C0-9F37-11CE-AE65-08002B2E1262}\InProcServer32\(default) =
"C:\\WINDOWS\\SYSTEM\\ShellExt\\CabView.dll"
and
HKEY_CLASSES_ROOT\CLSID\{0CD7A5C0-9F37-11CE-AE65-08002B2E1262}\InProcServer32\"ThreadingModel" =
"Apartment"
Of course you must also have a CLSID entry that matches
HKEY_CLASSES_ROOT\CLSID\{CLSID}
and the keys shown in Figure 4 under it.
The Cab File Viewer registers the extension under the file extension for CAB files, similar to the way you register context menu handlers, property sheet extensions, and other shell extensions.
HKEY_CLASSES_ROOT\.cab\(default)="CLSID\\{0CD7A5C0-
9F37-11CE-AE65-08002B2E1262}"
Then a key is created for the CLSID,
HKEY_CLASSES_ROOT\CLSID\{0CD7A5C0-9F37-11CE-AE65-08002B2E1262}
Next, the following entries are added. Note the reference to the CLSID for the CabView.dll and the rooted Explorer.
HKEY_CLASSES_ROOT\CLSID\{0CD7A5C0-9F37-11CE-AE65-08002B2E1262}\InProcServer32\(default)=
"C:\\WINDOWS\\SYSTEM\\ShellExt\\CabView.dll"
HKEY_CLASSES_ROOT\CLSID\{0CD7A5C0-9F37-11CE-AE65-08002B2E1262}\InProcServer32\"ThreadingModel" =
"Apartment"
HKEY_CLASSES_ROOT\CLSID\{0CD7A5C0-9F37-11CE-AE65-08002B2E1262}\DefaultIcon\(default)=
"C:\\WINDOWS\\SYSTEM\\ShellExt\\CabView.dll"
HKEY_CLASSES_ROOT\CLSID\{0CD7A5C0-9F37-11CE-AE65-08002B2E1262}\shell\open\command\(default)= "Explorer /
root,{0CD7A5C0-9F37-11CE-AE65-08002B2E1262},%1"
Explorer invokes your extension using the exact command line you registered, so you can test your command line by executing it directly with the Run command on the Start menu. For example, executing
Explorer.exe /root, {your CLSID}, [path]
should start up the Explorer and your extension.
Shell extensions are code that modifies or enhances the functionality of the entire operating system shell. Name space extensions are just one type of shell extension. Therefore, all name space extensions are shell extensions. Because of this, there is some standard shell extension code you will need to use when writing your name space extension (which I will cover in a moment).
Let me clear something up. The terms "shell" and "Explorer" are often used interchangeably in some of Microsoft's documentation. This is because Explorer.exe is the entire Windows shell. A shell extension is in fact an Explorer extension. It is confusing because most people think of the Explorer as the window (shown in Figure 5) that explores the name space. Explorer is also the application that owns and controls the desktop and the name space data. When you're implementing a name space extension (or any shell extension), think of the big picture as just a collection of shell extensions, all owned by Explorer. Other parts of Windows 95 system code also use these extensions, including the File Open and File Save common dialogs.
Figure 5 Explorer
A name space extension is to Explorer as an interpreter is to a tourist. Since your custom name space data is in a language Explorer does not natively know, your name space extension will translate your custom data to a format that Explorer can understand.
OK, so what's a browser? A browser is an application that interacts with the name space to provide the user with a visual representation and a mechanism to manipulate the data. The EnumDesk sample (see Figure 6) from the MSDN CD is a browser. The Explorer window in Figure 5 is also a browser. The goal of name space extensions is to eliminate the need to write a complete browser.
Figure 6 EnumDesk
A name space extension enables Explorer to let users view and manipulate custom data objects in familiar Explorer-like ways. Until now, developers wanting this level of integration had to implement their own custom browser (like EnumDesk) that handled their own data type information along with the standard name space. This meant that the user needed a different browser for each custom data type! Further, the custom browser solution doesn't allow you to take advantage of future enhancements in Explorer's browser technology (when Windows 2001 comes out, users won't want to be forced to still use EnumDesk!). With a name space extension, not only does the user only need one browser (Explorer's), but users will be able to take advantage of enhancements to Explorer and continue to use your data.
A name space extension allows you to define a new object that a name space browser like Explorer can explore and allows the user to interact with. Your extension code, which is implemented as an OLE inproc server, manages the display of the icon images and text that the user sees while viewing your data, as well as the menus and toolbars the user can use to interact with your data. This new object can be used for any number of things, including displaying the contents of your email inbox or Internet newsgroups, the contents of a zip file or a database of some sort, document management system or whatever, assuming that the information can be presented reasonably in a graphical way. Very sophisticated name space extensions can actually do things like take the symbol in your name space and decode it on the screen. An example would be if there was a URL in your name space, but you displayed the Web page in the browser instead of the URL. In this example, the data being displayed by the browser is not the actual data in the name space; instead it is something referenced by the data in the name space. However, deviating from name space extensions that essentially list items and attributes to full-featured document-style editing is better handled through ActiveX, which is not covered in this article.
To see an extension in action, download and install the Cab File Viewer, and then browse into a CAB file, such as the ones on your Windows 95 install CD or the Plus! Pack. Figure 7 shows a directory containing CAB files. Explorer recognizes the CAB file format once the viewer is installed, and displays the icons registered to the extension in the registry under the {CLSID}\DefaultIcon key. (In this case the icon is similar to the one displayed for directories.)
Figure 7 CAB Files
Nothing magic so far, since you can register an icon for almost any type of file. Open one of the CAB files and you'll see the extension in action (refer back to Figure 2). Notice how the contents of the CAB file appear as if the files were in a directory.
Cab File Viewer works by registering its file type, CAB, as a name space extension and provides the information required by Explorer to display its name space contents. In this case CAB File Viewer provides a list of file names, icons, and attributes just as if the CAB file was a directory containing files.
So what do you have to implement to create a name space extension? Your extension has to provide Explorer several things:
You probably feel like you have seen this before-the MFC document/view architecture works on a very similar fashion. The list of the IDs in the name space correlate to the MFC document object, and the view of the items relate to the MFC view object.
As mentioned earlier, all shell extensions (and hence your name space extension) must be implemented as OLE inproc DLLs. They must contain at least the functions DllMain, DllGetClassObject, DllCanUnloadNow, and the standard IUnknown interface. Finally, all shell extensions must be implemented using the apartment threading model. The apartment threading model allows your process to contain more than one thread of execution because it uses message passing to deal with multiple objects running concurrently.
That's what's required to create a basic, albeit bland, OLE inproc DLL that can be used as the frame for an extension. From there, extensions deviate since the interfaces and methods they support depend on the type of extension being implemented.
A name space extension must implement the IShellFolder, IEnumIDList, IPersistFolder and IShellView interfaces. Their methods (see Figure 8) are used to interact with Explorer. Explorer makes calls into the extensions using the IShellFolder and IShellView interfaces, and the extension can call back into Explorer using its IShellBrowser implementation.
Figure 8 Calling into a Name Space Extension
Once you have your core code, then you need to add the code that is specific to your name space. The "Name Space Extensions-Quick Reference" pullout (between pages 48 and 49) lists the key interfaces and their methods, as well as brief descriptions. The Win32 SDK and the MSDN CD contain complete descriptions of these interfaces, including parameter descriptions, return values and some sample usage code in some cases. These interfaces and methods are defined in ShlObj.h and ShlGuid.h, which have recently changed to include the new interface definitions necessary to implement name space extensions. These files will be included in the next Win32 SDK, but in the meantime you can find them with the sample code for this article.
When Explorer goes to display the contents of your name space, it loads your extension via OLE, using the CLSID you registered to locate your inproc server DLL. It then calls your extension's QueryInterface to get the interfaces and methods it needs. For example, Explorer will query for IPersistFolder once your DLL is loaded. If Explorer receives a valid interface pointer, it will initialize your code by calling the IPersistFolder::Initialize member and will pass your extension a pointer to an ID list (or PIDL). A PIDL points to a data structure that identifies your code in the overall name space.
An ID list is a group of shell item IDs. Each identifier is an array of bytes that contains data specific to the name space code that allocated the identifier. The first two bytes of this array must be a byte count that defines the length of the item, but the rest of the data is not used by any code outside the name space extension. The rest of the data identifies the item to the name space extension that allocated it. For example, an identifier that points to a file on disk may be as follows:
Bytes 0-1
Byte count
Bytes 2-n
Full path
If the name space extension wants to cache away details, it could make the identifier as follows:
Bytes 2-258
Path and file name
Bytes 259-260
File's size in bytes
Bytes 260-261
Create date
Bytes 262-263
Attributes
Bytes 264-n
Icon
In this case, caching away the file details speeds up the name space's responses to Explorer's queries, which improves UI performance.
When these identifiers are formed into an ID list, they are simply concatenated one after another and a final ID with a zero byte count is used as a terminator. An ID list that contains only one ID is called a simple ID list, one with more than one ID is called a complex ID list. For consistency, most methods that accept a shell item ID as a parameter take a PIDL, although you must watch out since some methods expect simple ID lists and others can handle complex ID lists. For example, CompareIDs, GetAttributesOf, GetUIObjectOf, and SetNameOf expect simple ID lists, while BindToObject, BindToStorage, and GetDisplayNameOf can be passed complex ID lists. The documentation indicates which methods handle complex ID lists.
Using a directory structure as an analogy for the name space, a PIDL can be compared to a path. Just as there are absolute and relative paths in DirectoryStructureLand, there are absolute and relative PIDLs. A relative PIDL is only meaningful inside its name space location. In the case of a name space extension's items, the PIDL is pointing to a buffer of data that only has meaning to the name space extension itself. Since this item can be any structure you wish, you may want to include information such as a friendly name, actual location, attributes, and other details that the extension can use for speedy access.
An important note about ID lists is that they must not be dependent on where they are stored in memory. They cannot contain pointers to data within themselves or any data external to them. This is because an ID list can be saved to persistent storage (for example, shortcut files contain a persisted ID list), and then read back into memory later and presented back to the IShellFolder that first enumerated the item (except the ID list is now in a different chunk of memory). An ID list can also be duplicated into another memory block, and then be presented to the IShellFolder. In the example of an identifier that refers to a file on disk, this means that the identifier/structure pointed to by the PIDL must contain the actual path, not just a pointer to a character string that contains the path. The identifier must be
USHORT; char[__MAXPATH];
not
USHORT; char*;
This also means all IShellFolder implementations need to be both backward- and forward-compatible with ID lists that they write out. That is, if the ID list format for a folder is revised, it must work well (not crash!) with old and new implementations of the IShellFolder. Be very careful when designing the format of your ID lists. A very good way to do this is to have an ID type field immediately after the byte count. For example, while bytes 0-1 are used to indicate the byte count for the ID, bytes 2-3 should be used to "tag" the rest of the data in the ID with some format code. If the name space extension does not recognize the format code, it knows (from the byte count) how many bytes to skip, and therefore can ignore the ID gracefully.
Once initialized, Explorer will request an IShellFolder interface to access information about your name space's contents. Explorer uses IShellFolder::EnumObjects to get a list of your extension's contents, IShellFolder::GetUIObjectOf to get the appropriate icons and menus, and IShellFolder::GetAttributesOf to get various attributes of each item, including whether or not that item has subfolders. Since the contents of your name space are known only to your name space extension, all information required by Explorer regarding your data must be implemented by your name space extension code.
How does Explorer walk through the items in your name space and identify each one to your code when it needs a menu or an icon? This is where the PIDL comes in. Explorer walks through your identifiers using your name space extension's exposed IEnumIDList interface to get each item's PIDL.
Because Explorer calls IShellFolder::CompareIDs to locate an item in your name space using an identifier you returned earlier, you must be consistent with your IDs. CompareIDs is also used when sorting lists such as the tree in the Explorer. Explorer can also use CompareIDs to check whether or not two PIDLs actually point to the same object.
The IShellBrowser interface (also shown in the "Name Space Extensions-Quick Reference" pullout) is implemented within Explorer, not your name space extension code. It provides a way for your extension to communicate back to the Explorer with visible feedback to the user, including menus, status text, and toolbars. IShellBrowser also gives you a private stream to store persistent state information, such as the layout of items, the viewing mode selected (large icon, small icon, list, or details) or whatever the extension might need the next time this name space is explored.
When the user enters or opens a name space extension, Explorer must create a view object to display the contents. This is done by calling the name space extension's IShellFolder::CreateViewObject member function and getting an IShellView interface. The Explorer then calls IShellView::CreateViewWindow, which tells the extension to create the view of its folder's contents. Typically you would use a listview control to display your contents, as the Cab File Viewer does. Your extension uses the IShellBrowser::GetWindow method to get a window handle of its parent and it passes a RECT pointer to determine the window's position.
When the Explorer calls IShellView::CreateViewWindow, it passes an IShellBrowser interface pointer, which allows the extension to call back into Explorer to add status information, menus, and toolbar buttons. The relationship between the IShellBrowser and IShellView interfaces is similar to that of IOleInPlaceFrame and IOleActiveObject.
The UI mechanism used is similar to OLE's in-place activation mechanism, with a few differences. First, the view window, which the extension creates, can exist even though it may not have the input focus. It has to maintain three states: deactivated, activated with focus, and activated without focus. The view window can present a different set of menus depending on the state. Explorer notifies the extension of any state changes by calling its IShellView::UIActivate member. The Shell View object, in return, calls IShellBrowser::OnViewWindowActivate when the view window is activated by the user with a mouse click.
Unlike a typical OLE in-place activation, Explorer does not support any type of layout negotiation, but it does let the view window add toolbar buttons and set status bar text, and the view window can communicate with these controls through calls to IShellBrowser::GetControlWindow or IShellBrowser::SendControlMsg.
Finally, Explorer allows the view window to add menu items to its pulldown menus and insert top-level pulldown menus. The view object is allowed to insert menu items to submenus returned from IShellBrowser::InsertMenusSB. For Explorer to dispatch menu messages correctly, menu item IDs must be between FCIDM_SHVIEWFIRST and FCIDM_SHVIEWLAST, which are defined in the ShlObj.h file. While OLE's standard in-place mechanism allows the UI active object to add pull-down menus (where you don't need to worry about menu item IDs), the shell's UI negotiation mechanism also allows the active view to add menu items to parents' pull-down menus. Action menu items (such as Open or Cut) should only be available if the view is activated with focus. This is done by manipulating the menu attached to the control window via standard Win32 menu APIs.
When you navigate around the name space on your computer, you are going to be bouncing around all different types of name spaces and associated views. For example, you may click on the Control Panel folder in the left pane of Explorer and then click on the folder CHEESE.CHZ under the Drive C: folder. In this example, your view changes from a Control Panel applet view to a file directory view.
To keep the user from going batty, Explorer strives to keep the same look and feel when switching views. If you were in Details mode when looking at Control Panel, Explorer assumes you want to look at the file directory in details mode also. Explorer maintains a little data structure called State Information that's passed from the soon-to-disappear view to the soon-to-appear view. In the example mentioned above, the State Information would indicate Details mode.
When your view window is created, you are given this State Information as a parameter in your IShellView::CreateViewWindow method. Likewise, your IShellView::GetCurrentInfo method must supply this State Information when it is called by Explorer.
For consistency, Explorer passes a pointer to the IShellView interface used for the previously active view as a parameter to your IShellView::CreateViewWindow before calling the previously active view's DestroyViewWindow. This allows your view object to transfer appropriate state information from the previous view object.
The IShellBrowser::GetViewStateStream method gets a pointer to a stream to store your state and attribute settings when your IShellView::SaveViewState method is called. This gives you a place to store the current view settings so you can restore them in your next session.
Figure 9 is a table that lists the files in the Cab File Viewer, the interface(s) implemented in the file, highlighting those covered here. The files are excerpted in Figure 10. I'm not going to walk through the code, but it's a good idea to review it and use it as a reference for adding features to your own name space extension. One of the best places to look for information regarding shell interfaces is the SHLOBJ.H file itself.
Debugging shell extensions can be tricky and name space extensions are no exception. My favorite method is to use the Just-in-Time debugging capabilities of Visual C++¨ 4.x. I code a DebugBreak into my extension at a strategic location and let Windows 95 invoke the debugger automatically for me when the DebugBreak statement is executed. The nice thing about the DebugBreak API is that you don't have to exit Explorer and restart it within the debugger. The extension is running under the same circumstances it will ultimately be running in when it's complete. At the point where I hit the DebugBreak call, I'll be looking at the assembly language. If I step out of that function and close the assembly window I'll be looking at my source code, which Visual C++ automatically locates and loads. The other nice thing about using DebugBreak is that you can program the DebugBreak statement to be hit under a certain set of circumstances, for example, if a flag changes state or a counter drops below zero or whatever.
Now that you're having fun debugging your extension, here are a couple of common implementation errors to watch for. First, all accesses to nonconstant global variables of DLLs must be serialized by a critical section or a mutex. Otherwise, you risk having your global data manipulated unexpectedly by other threads. Second, objects returned from IShellView::CreateViewObject or IShellView::GetUIObjectOf(IShellView, IDropTarget, IContextMenu, and so on) must be newly allocated each time they're called. Implementing an IShellView interface in the same object that implements IShellFolder (using C++ multiple inheritance) is a very common mistake. Having a pointer to your IShellView in the IShellFolder object is another bad idea, since one IShellFolder object can have multiple dynamically changing views.
So far I've discussed only a basic implementation of a namespace extension that can be viewed from Explorer. Your extension can implement much more: drag and drop, printing, copying, toolbars, and so on. The following can be used to enhance the functionality of your name space extension.
IExtractIcon can be implemented to provide custom "on-the-fly" icons for different data types within your name space. To support drag and drop, your view must support the standard OLE IDropSource and/or IDropTarget interfaces, depending on whether you want to support dragging, dropping, or both. IContextMenu interface can be implemented to provide context menus for your items.
Almost any extension written for Windows 95 should work on Windows NT 4.0 (with the same compatibility considerations as apps) with only an additional registry key, and if you are writing a shell extension for Windows 95 you should take the extra time to test your application on the Windows NT 4.0 beta currently available.
I cannot stress enough the importance of testing your extension carefully on both Windows 95 and Windows NT 4.0. Although the systems strive for compatibility, they are separate operating systems and there can be differences. While most differences encountered are minor, they are much easier to fix before you release your code than after.
Make sure your code checks the platform it's running on and uses only features that are available on that platform. Although almost all Win32 API are supported on both, the Win32 SDK does contain some that are targeted at a specific platform. (The Win32 SDK documentation can tell you which APIs are platform-specific.)
The Microsoft Knowledgebase Article Q92395 contains information on determining the platform you are running on. At the very least give the user a reasonable message saying that this platform is not supported, such as "Tough luck, Bozo!"
For the vast majority of shell extensions, the only new requirement for Windows NT is that it has an "approved" list of shell extensions in the registry and you must add yourself to this list before your shell extension will run.
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WindowsNT\CurrentVersion\
ShellExtensions\Approved\{CLSID}="Name of Extension"
The only other thing to be aware of is that Windows NT also provides UNICODEª support for shell extensions, although it is compatible with the Windows 95 ANSI implementations.
One of the more tedious tasks of developing name space extensions is that you have to implement a fair number of small methods that barely change from implementation to implementation to be fully consistent with Windows and the internal name space. In fact, many are implemented by the shell itself. It would be nice if a custom name space implementation could aggregate the existing shell interfaces, allowing developers to concentrate on customizing a particular area, rather than having to totally redevelop entire interfaces. Hopefully this will change in a future version.
Finally, remember that question: "Just because you can do it, should you?" I bring this up not to discourage you from using the name space extension mechanism, but rather to provoke you into thinking carefully about what you are trying to accomplish and whether or not it's the best solution. A name space extension is a complex piece of code and may be overkill in many cases. Sometimes just registering an application and its data file type in the registry is what you really want.
The author would like to thank Dhananjay Mahajan, Chris Guzak, Satoshi Nakajima, Mary Kirtland, and Francis Hogle for their help. | http://www.microsoft.com/msj/archive/S332.aspx | crawl-002 | refinedweb | 5,943 | 59.74 |
setjmp - set jump point for a non-local goto
#include <setjmp.h> int setjmp(jmp_buf env);
A call to setjmp(), saves the calling environment in its env argument for later use by longjmp().
It is unspecified whether setjmp() is a macro or a function. If a macro definition is suppressed in order to access an actual function, or a program defines an external identifier with the name setjmp the behaviour is undefined.
All accessible objects have values as of the time longjmp() was called, except that the values of objects of automatic storage duration which are local to the function containing the invocation of the corresponding setjmp() which do not have volatile-qualified type and which are changed between the setjmp() invocation and longjmp() call are indeterminate.
An invocation of set direct invocation, setjmp() returns 0. If the return is from a call to longjmp(), setjmp() returns a non-zero value.
No errors are defined.
None.
In general, sigsetjmp() is more useful in dealing with errors and interrupts encountered in a low-level subroutine of a program.
None.
longjmp(), sigsetjmp(), <setjmp.h>.
Derived from Issue 1 of the SVID. | http://pubs.opengroup.org/onlinepubs/7990989775/xsh/setjmp.html | CC-MAIN-2015-18 | refinedweb | 189 | 54.73 |
Convert unix time to readable date in pandas DataFrame
I have a data frame with unix times and prices in it. I want to convert the index column so that it shows in human readable dates. So for instance i have "date" as 1349633705 in the index column but I'd want it to show as 10/07/2012 (or at least 10/07/2012 18:15). For some context, here is the code I'm working with and what I've tried already:
import json import urllib2 from datetime import datetime response = urllib2.urlopen('') data = json.load(response) df = DataFrame(data['values']) df.columns = ["date","price"] #convert dates df.date = df.date.apply(lambda d: datetime.strptime(d, "%Y-%m-%d")) df.index = df.date df
As you can see I'm using
df.date = df.date.apply(lambda d: datetime.strptime(d, "%Y-%m-%d")) here which doesn't work since I'm working with integers, not strings. I think I need to use
datetime.date.fromtimestamp but I'm not quite sure how to apply this to the whole of df.date. Thanks.
These appear to be seconds since epoch.
In [20]: df = DataFrame(data['values']) In [21]: df.columns = ["date","price"] In [22]: df Out[22]: <class 'pandas.core.frame.DataFrame'> Int64Index: 358 entries, 0 to 357 Data columns (total 2 columns): date 358 non-null values price 358 non-null values dtypes: float64(1), int64(1) In [23]: df.head() Out[23]: date price 0 1349720105 12.08 1 1349806505 12.35 2 1349892905 12.15 3 1349979305 12.19 4 1350065705 12.15 In [25]: df['date'] = pd.to_datetime(df['date'],unit='s') In [26]: df.head() Out[26]: date price 0 2012-10-08 18:15:05 12.08 1 2012-10-09 18:15:05 12.35 2 2012-10-10 18:15:05 12.15 3 2012-10-11 18:15:05 12.19 4 2012-10-12 18:15:05 12.15 In [27]: df.dtypes Out[27]: date datetime64[ns] price float64 dtype: object
From: stackoverflow.com/q/19231871 | https://python-decompiler.com/article/2013-10/convert-unix-time-to-readable-date-in-pandas-dataframe | CC-MAIN-2019-47 | refinedweb | 350 | 80.38 |
Tim: Timed iteration monitorTim: Timed iteration monitor
A common pattern I have when writing code to import or treat large chunk of data is to do some printing to track the progress and some timing to monitor the speed. So I often end up with some variation of this in my code:
from datetime import datetime start = datetime.now() n = 0 for i in my_iter: n+=1 print "\r", i, # do stuff print start - datetime.now() print (start - datetime.now()) / n / 100
which is a lot to remember and type which in turn make it easy to introduce bugs in some edge case which you need then to debug.
So I wrote tim to help me do just that, so I have this pattern ready for use and working and can spend my time coding my data treatment instead of debbugging my helper code.
WARNING : This is alpha level stuff, I'm still working out the proper way to do stuff so the API may still change a bit.
How to use timHow to use tim
Common usage pattern would probably be:
import tim tim.start() for i in my_iter: tim.pulse_print() # print current progress # do stuff tim.stop() # print overall stats and reset counter
If you just need to monitor start and stop you can use:
tim.start() # calculation tim.stop() # print elapsed time and reset
InstallationInstallation
pip install tim | https://libraries.io/pypi/tim | CC-MAIN-2021-21 | refinedweb | 231 | 71.14 |
Garry Saddington schrieb:
I have this page:
Advertising<frameset rows="75%,25%"> <frame src="<dtml-var page>"> <frame src="<dtml-call"> </frameset>The 'page' variable is in the request but no matter what I try I am having problems passing it the the python script 'getproperty'. Can anyone point me in the correct direction?
dtml-call? wtf! This will never ever work since dtml-call does not return values. You might want to use dtml-var instead. (Let alone you should try to not use dtml at all) You above example would also not work since _['page'] would read a variable named page from _ namespace, which would try to look up properties first and only as last resort look for request variables. There is REQUEST even in DTML. Also note, design has long since moved away from frames (Yes I know ZMI still uses them) - it makes things with application servers much more easy if you don't use frames. Easiest way is to return rendered pages from python script for example pagename=context.getProperty('page','defaultpage') return context[pagename]() as a python script would do the trick. Regards Tino _______________________________________________ Zope maillist - Zope@zope.org ** No cross posts or HTML encoding! **(Related lists - ) | https://www.mail-archive.com/zope@zope.org/msg27633.html | CC-MAIN-2016-50 | refinedweb | 206 | 71.24 |
i know im doing this really wrong help if possible (trying to set the target automatically on start up to the player (PC) but unsure how i know every thing i has work when i drag the object to the target but i need to auto target
/// /// EnemyAttack.cs /// Oct 20, 2010
/// /// This is a very basic Mob Attack script that we are going to use to get use to coding in C# and Unity /// /// This script is ment to be attached to a mob, or a mob prefab /// using UnityEngine; using System.Collections;
public class EnemyAttack : MonoBehaviour { public GameObject target; public float attackTimer; public float coolDown;
public string playertarget;
// Use this for initialization
void Start () {
attackTimer = 0;
coolDown = 2.5f;
PC = GameObject.FindGameObjectWithTag("PC");
}
// Update is called once per frame
void Update () {
if(attackTimer > 0)
attackTimer -= Time.deltaTime;
if(attackTimer < 0)
attackTimer = 0;
if(attackTimer == 0) {
Attack();
attackTimer = coolDown;
PC.PLAYER_TAG("PC")// i know im doing this really wrong help if possible (trying to set the target automaticly on start up to the player (PC)
//but unsure how i know every thing i has work when i drag the object to the target but i need to auto target
}
}
private void Attack() {
float distance = Vector3.Distance(target.transform.position, transform.position);
Vector3 dir = (target.transform.position - transform.position).normalized;
float direction = Vector3.Dot(dir, transform.forward);
if(distance < 2.5f) {
if(direction > 0) {
PlayerHealth eh = (PlayerHealth)target.GetComponent("PlayerHealth");
eh.AddjustCurrentHealth(-10);
}
}
}
}
Answer by getyour411
·
Sep 11, 2013 at 03:07 AM
change this
PC = GameObject.FindGameObjectWithTag("PC");
to this
target = GameObject.FindGameObjectWithTag("PC");
get rid of this
PC.PLAYER_TAG("PC")
i have no erros but it dosent auto target the Tagged gameobject PC
nvm i figured out what i did the target was tagged as Player not PC thanks a lot Cars not working
1
Answer
c# how to refresh my targeting list
2
Answers
Character doesn't stop and sits on top of target.
1
Answer
c# help fix argument is out of range error
1
Answer
New to Unity, Need Help.
1
Answer
EnterpriseSocial Q&A | https://answers.unity.com/questions/534511/how-can-i-auto-target-gameobject-on-startup.html | CC-MAIN-2021-17 | refinedweb | 350 | 53 |
I have a list that I generated using a for loop. it returns:
home1-0002_UUID 3457077784 2132011944 1307504896 62%
home1-0003_UUID 3457077784 2088064860 1351451980 61%
home1-0001_UUID 3457077784 2092270236 1347246604 61%
for index, elem in enumerate(my_list):
print (index,elem)
def h1ost():
p1 = subprocess.Popen("/opt/lustre-gem_s/default/bin/lfs df /lustre/home1 | sort -r -nk5",stdout=subprocess.PIPE, shell=True)
use = p1.communicate()[0]
for o in use.split('\n')[:6]:
if "Available" not in o and "summary" not in o:
print (o)
As far as I cannot post a comment I will do my best to give you a solution to the question.
def empty_string_filter(value): return value != '' def h1ost(): p1 = subprocess.Popen("/opt/lustre-gem_s/default/bin/lfs df /lustre/home1 | sort -r -nk5",stdout=subprocess.PIPE, shell=True) use = p1.communicate()[0] third_column_list = [] fifth_column_list = [] # Separate by line break and filter any empty string filtered_use_list = filter(empty_string_filter, use.split('\n')[:6]) for line in filtered_use_list : # Split the line and filter the empty strings in order to keep only # columns with information split_line = filter(empty_string_filter, line.split(' ')) # Beware! This will only work if each line has 5 or more data columns # I guess the correct option is to check if it has at least 5 columns # and if it hasn't do not store the information or raise an exception. # It's up to you. third_column_list.append(split_line[2]) fifth_column_list.append(split_line[4]) return third_column_list, fifth_column_list
So the idea is split every single line by white spaces and filter any empty string left in order to get the 3rd and 5th column (index 2 and 4 respectively)
Note that i'm returning a two lists: one with the content of the 3rd column and another for the 5th column | https://codedump.io/share/kc7JaiB5PACo/1/python-how-to-return-2-columnsindex-in-a-list | CC-MAIN-2017-26 | refinedweb | 292 | 55.24 |
Opened 8 years ago
Closed 8 years ago
Last modified 8 years ago
#2154 closed merge (fixed)
Stack overflow due to unsafePerformIO
Description
The following program, extracted from a utf8 decoder for ByteStrings, overflows the stack when run with rules on. Speaking to SimonM, this is due to the stack squeezing optimisation not working for unsafePerformIO, meaning the resulting loop actually uses up stack.
import qualified Data.ByteString.Char8 as S main = putStrLn $ filter (\x -> enc x /= [x]) list where list = ['\0'..'\x10ffff'] ++ ['\0'..'\10'] {-# NOINLINE enc #-} enc :: Char -> String enc x = S.singleton x `seq` [x]
After fusing and optimising, S.singleton here is allocated using unsafePerformIO to wrap the allocation, and seems to run out of stack.
However, I've confirmed this code does work if its changed to use unsafeDupablePerformIO.
I'm filing this ticket to get documentation on what is going on here, so we can have something to point to if it comes up again, and to clarify that unsafeDupablePerformIO is the correct fix.
SimonM, could you summarise what the issue is?
Change History (4)
comment:1 Changed 8 years ago by simonmar
- difficulty set to Unknown
- Milestone set to 6.8.3
- Owner set to igloo
- Type changed from bug to merge
comment:2 Changed 8 years ago by igloo
- Resolution set to fixed
- Status changed from new to closed
Merged
comment:3 Changed 8 years ago by simonmar
- Architecture changed from Unknown to Unknown/Multiple
comment:4 Changed 8 years ago by simonmar
- Operating System changed from Unknown to Unknown/Multiple
Fixed in this patch I committed yesterday: | https://ghc.haskell.org/trac/ghc/ticket/2154 | CC-MAIN-2016-18 | refinedweb | 265 | 58.82 |
I am a user of Ruby on Rails framework and am thinking of giving back to it by contributing to the code. I understand that there is a need for thorough understanding of the Ruby language concept to contribute? Ive cloned the project, looked at the code, check out the tickets and have no clue how to begin? From what i see the Rails Framework utilizes metaprogramming alot? So what other aspect of Ruby do i have to master in order to start contributing? or to contribute is to know the ins and outs of Ruby? Thank you.!
It has been quite awhile since I ran across ruby code I didn't understand, but there are parts of rails that really push my understanding of ruby.
That being said, even if you are at more of an intermediate level with the language, figuring out how rails works would probably be a great way to up your game.
As for where to begin, I would start by writing plugins. Think of a cool plugin you could write that hasn't been done yet, or something that you think you could do better. Whatever it is you want to do, chances are you are going to need to hook into some sort of rails internals to do it, which will give you a good place to start. Once you have a bit of knowledge of a given area of the framework, see if there are any open bugs in that area you can fix.
The barrier is quite high, since rails is a quite large and complex program written by people who have a high level of mastery with an incredibly flexible language. It is also a great challenge that will probably make you a better programmer in the end. :)
Edit: to help out banister
This is actually pretty interesting if it is a snippet designed to illustrate how class variables and singleton classes work, but there are much clearer ways to accomplish the same thing if it is "real" code.
Singleton Class
In ruby, every object has a parent class that it gets its methods from. This is pretty normal for OO languages. What isn't normal is ruby also has a concept called "object individuation, that means that objects can have methods that are only on a specific instance, but not on the parent class. here is a quick irb example
irb(main):001:0> foo = "bar" => "bar" irb(main):002:0> def foo.foo_method irb(main):003:1> "this is _only_ on the foo instance, not on all strings" irb(main):004:1> end => nil irb(main):005:0> foo.foo_method => "this is _only_ on the foo instance, not on all strings" irb(main):006:0> "bar".foo_method NoMethodError: undefined method `foo_method' for "bar":String from (irb):6 irb(main):007:0> foo = "New string" => "New string" irb(main):008:0> foo.foo_method NoMethodError: undefined method `foo_method' for "New string":String from (irb):8
First, we assign a string to a variable. Next, we define a method on that instance. Calling the method works, but calling it on a new string does not work. Assigning a new string instance to our foo variable also does not have that foo method.
To make object individuation possible, there needs to be something in between the instance, and the parent class. That thing is the singleton class, and every instance has one that is unique from all other object instances. When ruby is looking up a method, it will look at the singleton class before the parent class.
Believe it or not, even if you have never heard of this before, you have probably already used it. If you want to add a "class method" to something, you usually do this
class Foo def self.bar "i am on the class" end end Foo.bar #=> "I am on the class"
To start from the top, the statement
class Foo is the exact equivalent of this
Foo = Class.new do. What is happening is you are assigning a new instance of type Class to the constant Foo. (as an aside, this is what I love about ruby. most of the syntax is actually just sugar around some core concept)
Inside a class definition, self refers to the class, so saying
def self.bar is essentially saying "define the method bar on the singleton class of the Class instance that is stored in the constant Foo".
If you find this stuff complex, it is because it is. I don't think there is anything more complected in ruby other then what happens during method lookups, and singleton classes are a big part of what makes it so complex.
Class Variables
A class variable is prefixed by
@@, and basically is a variable whose scope is all instances, the class object, and all classes that inherit from the class. I'll do a quick irb to illustrate this in action
irb(main):003:0* class Foo irb(main):004:1> @@instance_count = 0 irb(main):005:1> irb(main):006:1* def initialize irb(main):007:2> @@instance_count += 1 irb(main):008:2> end irb(main):009:1> irb(main):010:1* def count irb(main):011:2> @@instance_count irb(main):012:2> end irb(main):013:1> end => nil irb(main):014:0> irb(main):015:0* class Bar < Foo irb(main):016:1> end => nil irb(main):017:0> irb(main):018:0* f = Foo.new => #<Foo:0x7fa9089c7da0> irb(main):019:0> f.count => 1 irb(main):020:0> irb(main):021:0* b = Bar.new => #<Bar:0x7fa9089be0e8> irb(main):022:0> b.count => 2 irb(main):023:0> irb(main):024:0* f.count => 2
First, we define Foo. Foo has a class variable that tracks how many instances were created. To do that, we increment that variable in the constructor, and lastly just define a quick getter. Bar just extends Foo.
Now, to see it in action, we make a new foo, and check the count, which is 1. Next, we create a new bar, and check the count, we are now at 2. Just to make sure that both Foo and Bar share the same count, we check our foo instance again, and it is 2 now.
Class variables are a very situational feature that you usually don't see outside of framework code. It is usually used when you want to keep track of all instances of a given class.
Banisters Code
class << Object.new @@var = 6 end String.class_variable_get(:@@var) #=> 6
Your code is showing those two concepts in action. First, we open up the singleton class of a new object, and put a class variable on it. If it were anything other then a class variable, those first three lines would be the most useless ruby code in the world. But since it is a class variable, that becomes visible to the class, all instances of the class, all classes that inherit from the class, and all instances of all classes that inherit from the class. Since the class we are talking about is object, that means everything. So doing class_variable_get on String gives it to you, but you could access that variable from any class or instance you wanted to.
I am sorry
This is horribly complected stuff that is very hard to explain clearly. These concepts took me about a week or so of fairly concerted effort to wrap my head around. If you have any questions about what I wrote, feel free to ask, but don't be discouraged if you don't "get it". | https://www.codesd.com/item/what-do-i-need-to-know-to-contribute-to-rails.html | CC-MAIN-2019-18 | refinedweb | 1,269 | 78.89 |
Hi guys, I'm at uni and I have some coursework involving a virtual line in C/C++.
The user should be able to input start and end coords (3D) of this line eg X1,Y1,Z1 and X2,Y2,Z2, and execute various transformations on the line as a whole around arbitrary points eg. rotation, translation etc.
Things is, I am stupid, and I don't even know how to set up a single 2D array to cope with this and then allow a user to modify the points in the array. I have a functioning-ish menu (see code below) but I haven't a clue about the important bits.
Could anyone please help me on how to get the array to show its six coordinates and then allow the user to modify them at least?
Thanks, Simon Phillips <spuk>
NB- can be written in C or C++
Code:
#include <stdio.h>
#include <stdlib.h> //required for user to exit program
#include <math.h> //needed to apply maths such as sin, cos etc.
int main()
{
double p1[3]={0,0,0};
double p2[3]={0,0,0};
int option;
for (;;)
{
printf("\nMAIN MENU\n");
printf("--------------------\n");
printf("1| Set Start Point\n"); //1. Sets start point of line
printf("2| Set End Point\n"); //2. Sets end point of line
printf("3| Apply Translations\n"); //3. Translates the line by user-selected amount
printf("4| Apply Rotation\n"); //4. Rotates the line by user-selected amount
printf("5| Apply Scaling\n"); //5. Scales the line by user-selected amount
printf("6| Evaluate Line\n"); //6. User selects a point along line between 0 and 1
printf("7| Exit Program\n"); //7. Finish using program
printf("\nPlease enter your choice:\t");
scanf("%d", &option); printf("\n");
printf("%lf\n", p1);
if (option==1);
else if (option==2);
else if (option==3);
else if (option==4);
else if (option==5);
else if (option==6);
else if (option==7)
{
printf ("Program terminated.\n\n");
exit(1);
}
else printf ("You have entered an incorrect value, please enter a number from the menu only.\n");// Tells user if wrong number entered
}
} | http://cboard.cprogramming.com/cplusplus-programming/72893-arrays-printable-thread.html | CC-MAIN-2016-07 | refinedweb | 358 | 73.07 |
>>.
ChromeOS criticism got knocked down a bit (Score)
Call me silly, but I think there is something to this "everything through the browser" malarkey. That's not to say everything should be on the cloud, but I don't see why we can't push non-critical functionality on rendering engines. A lot of mobile apps are just native interfaces to webservices anyway.
Wait, you want everything to run on a common software platform? How revolutionary. We could call it "Doorways", because the browser would provide a path to see into the possibilities. We could have a common add-on called "Glimmer" that provides additional functionality.
I can't picture any problems with such an approach.)
The cross-platform install process is easier with Javascript than just about anything else. That is the biggest win here -- beyond the idea of open source virtual worlds which others have done before. Perhaps that didn't used to be the case years ago, but it is now for any software that is going to quickly get mass adoption. Still, it's true that Android and iOS both try to make that easy -- if you've bought special hardware. HTML5 and related technologies like WebGL are trying to create standards for being
Re: (Score:2)
For me, Firefox 18 was unresponsive for a minute or so while loading one of the voxel.js demos. It eventually loaded. I have reported the issue as [mozilla.org].
Re: (Score:2)
Re: (Score:2)
Re: (Score:2)
I reported the issue to Mozilla (as per the link in my previous post) so they can investigate and improve things on their end. This should then benefit other complex JavaScript/WebGL applications, especially if the voxel.js code is used in web-based games and other applications.
Works fine in Chromium (Score:2)
Thanks for the info. I ended up installing Chromium to run it.
As "eksith" points out in another reply, everything has hiccups at first. The important thing is that this is working with technology that is based around open standards. And the design is modular and expandable.
Re: (Score:2)
Re: (Score:3)
Good points. I've been feeling more-and-more lately that "if something does not have a URL, it is broken".
:-)
And Minecraft worlds don't have URLs. Voxel.js world do. A simple seeming difference, but the implications are huge about sharing, discovering, mashups, archiving, expanding, and so on.
Here is a discussion where I explain that idea in more detail, that it's not so much the idea of a desktop app that is broken as the idea of an app without book-markable exchangeable URLs: [barcamp.org]
Re: (Score:2)
Chromium, Firefox (and kids), Opera, WebKit (and co)... pick your poison. My point was that the browser is a handy tool to publish applications and a lot of native applications can be made more easily cross-platform through web standards.
Think of it as the corollary to "everything is a file": "Everything is a service*" to be consumed by the browser.
*And by everything, I mean what makes sense to be on the browser. I.E. Documents, chat etc...
Re: (Score:3)
Because the carriers are gonna buttfuck us with ever worsening caps instead of spending any of their massive profits to lay the lines we already paid 200 billion plus [pbs.org] to have laid down?
All this "in the cloud" horseshit requires that we have a steady, reliable, fast and CAP FREE net connection or at least caps that are sane and which go UP in time. What we are seeing is the exact opposite with many places giving crappy caps to start with and as they oversell the shit out of their lines the caps get smaller N
Re: (Score:2)
Compare that with James J Hill, who built his
Re: (Score:2)
Funny Crosshair as I would say it is LACK of regulations that caused this mess. When the fed forced ma bell to open up their lines suddenly dialup went from an expensive hobby VERY few could enjoy to something so cheap many places would give you free time limited dialup in the hopes of selling you other services.
Then along comes Reagan and the DEregulators and suddenly it isn't illegal for these corps to just buy up the competition, or to buy services and media cartels that would put them in obvious conflic
Re: (Score:2).)
AC wrote: "needs webgl to run, I think that would have been more important to mention than the whole js thing?"
Good point, AC. I should have mentioned WebGL in the article summary. That is the probably the biggest stumbling block for lots of people running this. That was a problem I myself encountered with a crashing problem with Firefox 18 when I enabled WebGL, and worked around that by trying Voxel.js in Chromium, the open source version of Chrome. Still, in another couple of years, I would think WebGL..?
Blog post with more background info (Score:5, Informative)
Thanks, Max! (Score:3)
Great blog post, Max. Thanks for chiming in. I've enjoyed your previous instructional materials about CouchDB and other things like "JavaScript for Cats". [jsforcats.com]
So far our cat has only expressed limited interest in that website, but maybe over time interest will pick up?
:-)
For some reason, I think it would be really cool to put some sort of Couch-like database backend to this, even though I can't think of what it could be used for?
:-) But that is the beauty of your well-architected modular a
Re: (Score:1)
Re: (Score:2)
Maybe a way to get more support for this work: [knightfoundation.org]
Re: (Score:2)
.
Re: (Score:1)
Re: (Score:2))
And statements like that are just as bad as his, and mister AC above.
Worse. A simple sentence implying the writer does not like particular language without giving any explanation in article where it's not really even the subject is minor flaw, if even that. Calling someone a retard for this is sign of some major behavior issues.
I know I would be slightly annoyed if someone said the same, but about perl - I would not automatically think that the person is retard or even that he doesn't understand perl (although it's a possibility). All in all it would be of very small signifi
Faster than Minecraft for me (Score:3)
You may have found it slow, but I have found it faster than Minecraft on a desktop (Mac Pro with eight 2.8 Ghz Intel Xeon cores, where only 60%-75% of one core seems to be used by Voxel.js under Chromium). Granted, Voxel.js may be doing a lot less than Minecraft, or the demo worlds may be smaller, I don't know, so this is not a comprehensive comparison. But at least for something simple, Voxel.js seems very useable on a Mac desktop that is more than four years old and does not have especially fancy graphics)
The goal of Minecraft et al. is to provide very large (or sometimes truly infinite worlds). To achieve this you have to use extremely efficient memory storage. I don't know the actual figures but I assume Minecraft stores one or two bytes per voxel, which are approximately 1 cubit-foot, so a very efficient representation.
This simply isn't enough memory to store more then a few shapes (though a sphere dose seem a good choice).
Re: (Score:2)
They would be really flat people too.
Really it's 1.6 tall. And it's in meters, which is actually legit.
As XKCD teaches us 1.6 meters is about a CD diameter shorter than Summer Glau and about doorway width longer than a light saber blade.
Re: (Score:2)
A cubic meter, actually, I believe.. two blocks are just bigger than the player.
But that's not really all that efficient of a storage representation. By far, most of the blocks in the game are of two main type - air and stone - and almost every structure in the game is composed of some volume of mostly homogeneous blocks with perhaps smaller volumes of homogenous blocks suspended almost vacuole-like inside it - It might well be possible to more efficiently describe the landscape using the surfaces rather)
In terms of graphics, it wouldn't be so hard to make surfaces a little bit more varied. Why the blockiness in Minecraft? Why not give people roundish and triangular things to play around with too?
If you don't want to play the game, that's perfectly OK. Not every game is everyone's cup of tea.
But you could at least look at it before passing judgement.
There are far more shapes in Minecraft than just blocks. In fact of all the items, blocks are a minority.
Look at the bottom of this wiki page: [minecraftwiki.net]
Each and every one of those things is a non-block shape!
Or here for larger icons of items (including blocks): [alymma.com]
Slimeballs and snowballs)
The rudimentary blocks are just a few bytes each.
But there are a lot of them.
Just one player has about 4 million blocks around them loaded, more if they're moving around a bit. Then there are all the entities, light values, special blocks and such. The world is split into 'regions' and 'chunks'. A chunk is 16x16 blocks, from 0 to 255 height.
The blockiness is to make it a hell of a lot easier to modify the environment in predictable ways. It also lends itself to modding.
You get things like 'Feed the Beast',)
Max, on voxeljs.com, there are two demos which work fine but have broken source code links to go to missing GItHub pages (the first and eighth demo): [github.com] [github.com]
Anyway, it's been great fun playing with the demos -- especially the surprising voxel-portal one. At first I thought the behavior was a bug, and then I realized it was a feature -- wow!
:-) [substack.net]
It's just amazing to think I can, as above, supply)
I don't really see the point. it's nice, but it's not novel.
Why not just a Java Web Start with [jmonkeyengine.com]
You could even run that in the web browser with a Java Applet.
It would run with 200 fps (or more) and not with the lousy 22 fps what I get in the browser. And it would be cross-platform, too.
Sorry, I don't really see the point to re-implement everything we have on the desktop now in the browser. It's like we throw everything we achieved in the last 25 years on the desktop in the trash for
Re: (Score:1)
Re: (Score:2)
Lets ignore the fact that its 3d for a moment and concentrate on your main points... Is it novel? yes i personally thing so, but novel is in the eyes of the beholder. Is it awesome? absolutely from a developer point of view... is it cross platform - yes it is. Chrome and firefox can both be downloaded for every platform that oracle java can be (and probably built for many more too).
Then theres the version dependency fun. Consider i wrote a RTF document editor as java applet, im faced with the scenario of 3)
Oh, lots. It's much easier to reorganize minimized JS than to figure out disassembled code. Javascript runs several layers of abstraction above the CPU, and every call belongs in a tiny namespace, compared to what happens in assembler. It's comparing apples and industrial orange juice.
Let's be nice today shall we? (Score:1)
Extremely slow (Score:1)
I just tried it.
It barely runs at all. It's extremely slow. At 20-25 fps, walking feels more like crawling, and it uses all my computer resources, fans running as loud as they can, showing 100% CPU usage on two threads + GPU usage.
There is no point if the experience cannot at least as smooth as Minecraft.
What hardware/OS/browser? (Score:2)
Can you say what browser, OS, and hardware you tried it on?
Voxel.js was snappy when I tried it with Chromium on a Mac Pro desktop (vintage about four-five years ago with 2.8 Ghz Intel Xeon, fairly stock graphics card). It seemed to run even faster than Minecraft (granted it was probably doing a lot less with demo worlds).)
... to get supercool authoring. As part of AgentCubes, a 3D creativity tool supporting Casual 3D design, we have created a new kind of a 3D authoring tool. Casual 3D, similarly to Voxel or Minecraft is not aimed at Pixar animators but at people who have not done any 3D authoring before and would not want to spend more than a minute to get started. Imagine combining Inflatable Icons with Voxel. One could build some pretty cool worlds and program them. You can see an early draft of a short demo video below. I
Ready Player One (Score:1) | https://games.slashdot.org/story/13/01/26/1857209/voxeljs-minecraft-like-browser-based-games-but-open-source?sdsrc=prev | CC-MAIN-2016-30 | refinedweb | 2,192 | 72.87 |
IRC log of tagmem on 2009-12-10
Timestamps are in UTC.
00:42:57 [Zakim]
Zakim has left #tagmem
00:49:48 [johnk]
johnk has joined #tagmem
01:15:43 [DanC_]
DanC_ has joined #tagmem
02:31:52 [johnk]
johnk has joined #tagmem
02:53:00 [noah]
noah has joined #tagmem
02:53:02 [noahm]
noahm has joined #tagmem
02:56:52 [noah]
noah has joined #tagmem
02:56:55 [noahm]
noahm has joined #tagmem
14:08:21 [RRSAgent]
RRSAgent has joined #tagmem
14:08:21 [RRSAgent]
logging to
14:08:55 [masinter]
ht: this idea is not mine -- been floating around, never been written down, so I thought it was time to do so. I don't take credit for idea, but take blame for details.
14:09:11 [masinter]
... published in W3C blog.
14:09:21 [ht]
14:10:01 [Zakim]
Zakim has joined #tagmem
14:10:48 [masinter]
ht: criticism we've heard about namespaces are: syntactic complexity and API complexity issue. This proposal basically addresses the syntactic complexity, belief is that API can be handled later.
14:11:03 [masinter]
ht: slide 5 out of 7 already, just want to show example
14:12:51 [masinter]
... A "dpd" file gives default prefixes. One way to to give a link with rel="dpd" or for XML using a processing instruction. Or applications could ship in with a default DPD, or there could be media-type defaults.
14:13:10 [masinter]
... establish a priority order.
14:14:34 [masinter]
ht: In general, people are happy with using prefixing for avoiding collisions, but don't like namespace declarations, let's fix that.
14:15:20 [masinter]
tbl: We should investigate this sort of thing, going down this path is a good idea. I'm keen on getting them linked on the MIME type, why not do things at the MIME-type level.
14:15:53 [masinter]
... One technical issue ...
14:21:10 [DanC_]
DanC_ has joined #tagmem
14:57:36 [masinter]
((joined with xmlnames))
14:57:46 [masinter]
MikeSmith
15:05:27 [johnk]
johnk has joined #tagmem
15:06:22 [masinter]
scribenick: masinter
15:06:25 [masinter]
scribe: masinter
15:07:11 [masinter]
danc: neither of these proposals address interesting use cases
15:07:24 [masinter]
topic: xmlnames discussion
15:08:06 [noahm]
q?
15:08:41 [masinter]
danc: I can see two use cases: Person wants to write SVG without gobbledygook in top of document. <svg> is simpler than <svg:svg>.
15:08:57 [masinter]
... This doesn't seem to be on the road to decentralized extensibility
15:09:19 [masinter]
noah: you can change the link element or the linked DPD
15:09:33 [masinter]
danc: then you're back to gobbledygook at the top of the document
15:09:54 [masinter]
(tim drawing on whiteboard)
15:10:08 [masinter]
danc: I'm looking for use cases & cost benefit
15:11:05 [masinter]
timbl draws bar graph of document types. Most documents are HTML, but ther are SVG, MathML, FBML and lots of others.
15:11:12 [noahm]
q+ to noodle a bit on wild innovations evolving to the left of Tim's graph
15:11:25 [masinter]
(FBML is face book markup language)
15:12:17 [masinter]
(discussion about cost and benefits for various use cases)
15:13:00 [johnk]
I would like to see it be possible to have XHTML + XML namespaces then served as text/html be processed correctly
15:13:04 [masinter]
timbl: the issue is "in here" (pointing to HTML + popular other markups, SVG, etc.) but not minor
15:13:40 [masinter]
... languages that aren't used widely
15:14:36 [masinter]
danc: which are the interesting use cases? allowing svg namespace without declaration doesn't help deploy SVG, they still have to learn how to draw circles
15:15:22 [masinter]
noah: two communities invent <video> tag with conflicting meaning. To me the use case is "do you care about pollution"
15:16:18 [masinter]
(discussion about use cases and transition path)
15:16:34 [masinter]
danc: I'm trying to find some place where it's cost effective for someone
15:17:07 [masinter]
timbl: so you're saying there's nothing in the middle?
15:17:41 [masinter]
danc: svg and mathml are in the language. html5 does nothing interesting with rdfa.
15:18:00 [masinter]
danc: I'm still listening for the interesting use case.
15:18:18 [noahm]
ack next
15:18:20 [Zakim]
noahm, you wanted to noodle a bit on wild innovations evolving to the left of Tim's graph
15:19:29 [masinter]
noah: example about mosaic:img, worrying about long-term evolution is interesting
15:19:50 [masinter]
henry's proposal just gets rid of the xmlns:mosaic="
"
15:20:19 [DanC_]
no, it replaces it by <link ... ncsa>
15:20:53 [masinter]
... points out that "mosaic:img" would have been stuck with the prefix
15:21:17 [masinter]
timbl: we would have added img as an alternative to mosaic:img
15:21:44 [noahm]
q?
15:21:47 [masinter]
ht: yes, there are some bumps in the road, if we go this way. But if that's the only thing in the way, i think we can live with this.
15:21:48 [ht]
q+ to reply to DanC
15:21:56 [DanC_]
(I'm trying to find the details of the <link> syntax ; I don't see it in
, henry)
15:21:57 [masinter]
danc: when i think of this, i think of <canvas> which is more recent.
15:22:28 [masinter]
... as much as I hate x-, the most successful example is mos-.
15:22:39 [DanC_]
moz- in css
15:22:42 [noahm]
q?
15:22:55 [masinter]
noah: that works for css, but the rules are different for css, won't work for paragraph names
15:23:00 [DanC_]
but yes, the cascase is critical to the transition from moz-smellovision to smellovision
15:23:08 [DanC_]
cascade
15:23:41 [noahm]
cascase?
15:23:53 [masinter]
ht: wants to record two observations, different from dan. I don't agree, I think the current situation with SVG and MathML sucks. It has to define every possible transition. It specifies in detail where you can or can't put MathML and SVG elements.
15:24:14 [masinter]
ht: The fact that the SVG working group has been bullied into submission isn't good enough for me.
15:24:28 [masinter]
ht: They were pushed back to the current state of play. It isn't good enough for me.
15:24:36 [DanC_]
I think the SVG WG was convinced that this is simpler for authors
15:25:09 [noahm]
I would like to wrapup, get to next steps, and break
15:25:14 [masinter]
ht: It is interesting to say that the RDFa group is happy, because I don't think there is any place for namespace declarations, because the DOM isn't going to be what they want.
15:25:34 [masinter]
ht: I've recorded my disagreement
15:25:52 [ht]
s/place for/place in HTML5 wrt the HTML serialization for/
15:25:56 [masinter]
danc: the rdfa use case involves scripting
15:26:15 [masinter]
noah: what are next steps
15:27:02 [masinter]
action: noahm to work to schedule followup meeting on xmlnames next week
15:27:02 [trackbot]
Sorry, couldn't find user - noahm
15:27:14 [masinter]
action: noah to work to schedule followup meeting on xmlnames next week
15:27:14 [trackbot]
Created ACTION-356 - Work to schedule followup meeting on xmlnames next week [on Noah Mendelsohn - due 2009-12-17].
15:27:53 [masinter]
ht: reminds himself to work to figure out how this interacts with XML documents
15:27:54 [DanC_]
action-327?
15:27:54 [trackbot]
ACTION-327 -- Henry S. Thompson to review Microsoft's namespaces in HTML 5 proposal -- due 2009-11-19 -- PENDINGREVIEW
15:27:54 [trackbot]
15:29:22 [DanC_]
(do you remember the action #, larry? care to suggest a new due date?)
15:29:39 [ht]
ACTION: Henry to elaborate the DPD proposal to address comments from #xmlnames and tag f2f discussion of 2009-12-10, particularly wrt integration with XML specs and wrt motivation, due 2010-01-08
15:29:39 ].
15:29:46 [masinter]
action-337?
15:29:46 [trackbot]
ACTION-337 -- Larry Masinter to frame the F2F agenda and preparation on metadata formats/representations -- due 2009-12-08 -- OPEN
15:29:46 [trackbot]
15:30:48 [ht]
trackbot, action-337 due 2010-01-08
15:30:49 [trackbot]
ACTION-337 frame the F2F agenda and preparation on metadata formats/representations due date now 2010-01-08
15:33:52 [masinter]
agenda?
15:34:05 [masinter]
(group on break)
15:39:07 [plh]
plh has joined #tagmem
15:40:51 [jar]
15:41:35 [jar]
sorry, false positive on my google search
15:52:38 [masinter]
reconvene
15:53:25 [Ashok]
Ashok has joined #tagmem
15:54:10 [masinter]
topic: agenda discussion (Philippe joins group)
15:54:22 [masinter]
action-327?
15:54:22 [trackbot]
ACTION-327 -- Henry S. Thompson to review Microsoft's namespaces in HTML 5 proposal -- due 2009-11-19 -- PENDINGREVIEW
15:54:22 [trackbot]
15:54:22 [DanC_]
action-327?
15:54:22 [trackbot]
ACTION-327 -- Henry S. Thompson to review Microsoft's namespaces in HTML 5 proposal -- due 2009-11-19 -- PENDINGREVIEW
15:54:24 [trackbot]
15:54:31 [masinter]
topic: action 327
15:54:31 [plh]
15:55:19 [masinter]
plh: not coverage between issues and change proposals
15:55:37 [masinter]
noah: would help to add issue names to table
15:56:09 [masinter]
noah: failure mode is that people don't notice
15:57:31 [masinter]
plh: issue 7 was closed. chairs are willing to reopen if there is no new information
15:58:12 [DanC_]
HTML WG issue 7 was video codecs
15:58:35 [DanC_]
(referring to issues by number only is an anti-pattern)
15:59:00 [masinter]
noah: go to namespace proposal/discussion
15:59:14 [masinter]
topic: namespaces in HTML
15:59:28 [masinter]
looking at Microsoft namespace proposal
15:59:57 [noahm]
We note that HTML issue 41 appears to be open
16:00:10 [DanC_]
HTML WG issue 41 is open, with no dead-man-switch yet issued
16:01:17 [masinter]
HT: imports a subset of XML namespace syntax into the HTML serialization. Core proposal is a duel of what we talked about earlier: allow xmlns:foo, and within that scope foo:xxx uses the namespace
16:01:32 [masinter]
timbl: identical to xmlns, with regard to prefixed names
16:01:44 [masinter]
ht: then it goes on to suggest a number of possible extensions
16:01:55 [DanC_]
(I wonder if everybody here is aware of the way HTML interacts with XPath in the case of unprefixed element names... maybe I'll q+)
16:01:58 [masinter]
ht: the addition of default namespace declarations
16:02:22 [masinter]
ht: I'm just telling you what it says
16:03:05 [masinter]
ht: then there is an additional proposal, to treat unbound prefixes as if they were identity-declared
16:03:39 [masinter]
ht: namespace spec says you "shouldn't" use relative URIs
16:04:08 [masinter]
(discussion of whether xmlns:udp="udp" is an error, a relative URL)
16:04:24 [masinter]
timbl: local namespace declarations are useful in (context missed)
16:04:36 [masinter]
ht: interesting idea, don't think it is going to fly
16:04:45 [masinter]
timbl: maybe want #udp, not udp
16:04:57 [masinter]
(speculation about what is deployed inside microsoft)
16:05:26 [masinter]
3. to define short namespace names for commonly-used namespaces
16:05:36 [masinter]
(timbl bangs head on wall)
16:06:17 [masinter]
16:07:01 [masinter]
plh: discussion on HTML was that this would break (something), and Microsoft needs to revised
16:07:34 [masinter]
ht: I think it is sound but doesn't address the two issues that other WG members had raised, (a) syntactic complexity and (b) API complexity
16:08:11 [masinter]
noah: do we have a sense of where this is going?
16:09:27 [masinter]
(speculation about what might happen in the HTML working group)
16:09:46 [DanC_]
q+
16:09:50 [masinter]
(review of HT email review of Microsoft's proposal)
16:09:53 [DanC_]
ack ht
16:09:53 [Zakim]
ht, you wanted to reply to DanC
16:10:05 [noahm]
ac2 next
16:10:07 [noahm]
ack next
16:10:54 [masinter]
danc: thanks for gathering all he facts. I think this is as good as it gets, though, disagree with conclusion. Henry's isn't simpler and Microsoft's is more like current namespaces.
16:11:07 [masinter]
timbl: use this for svg?
16:11:39 [masinter]
ht: orthogonal point -- stipulating that one of these proposals is adopted, opens the possibility but not necessity of revisiting the current embedding of SVG and MathML
16:12:09 [masinter]
timbl: and the <a> tag, that's done by context?
16:12:11 [masinter]
ht: yes
16:12:52 [masinter]
timbl: should the TAG endorse the microsoft proposal?
16:12:54 [noahm]
q+ to discuss tim's proposal
16:13:09 [DanC_]
+1 TAG endorsedd
16:13:18 [masinter]
jar: (put on the spot)
16:13:51 [masinter]
noah: would like to see something happen, but insofar as doing this by saying TAG isn't happy with Henry or Liam's proposal, not ready to do that
16:13:59 [masinter]
ack noahm
16:13:59 [Zakim]
noahm, you wanted to discuss tim's proposal
16:14:24 [noahm]
q+ timbl
16:14:40 [masinter]
jar: here's how to convince me -- hard for me to keep this in my head
16:14:50 [masinter]
ack timbl
16:15:00 [masinter]
timbl: I need the Microsoft one anyway for the long tail
16:15:18 [masinter]
ht: that's just not true. There's a place in HT for ideosyncratic use
16:15:42 [masinter]
(danc at board making matrix)
16:17:23 [masinter]
noah: (floating idea for TAG position about endorsing MS vs. others)
16:18:10 [masinter]
columns: DPD, MS xmlns, Liam's
16:18:25 [masinter]
rows: long tail, static scoping, ie, webkit, opera, mozilla
16:19:03 [masinter]
static scoping means: changing some other document doesn't change what foo:bar would mean
16:19:43 [masinter]
column Liam's renamed Unobtrusive Namespaces
16:21:00 [masinter]
discussion of what the rows IE, Webkit, Opera, Mozilla mean
16:21:49 [masinter]
jar: wondering if there's a null hypothesis? Maybe there's a 'status quo' column?
16:22:03 [masinter]
adding 4th column, "Standing WG"
16:24:00 [masinter]
adding rows for SVG, MathML, RDFa
16:24:26 [masinter]
adding examples of "Long Tail", FBML, SL = Second Life vs. SilverLight
16:24:37 [masinter]
ht: PLH, what do you think about this?
16:25:55 [masinter]
timbl: Were a browser manufacturer to change their attitude and implement application/xhtml+xml, would that make a difference?
16:26:27 [masinter]
noah: expected question to be 'does then the TAG care about this', and I think they do, because e.g., service provider doesn't allow people to set MIME type
16:26:34 [jar]
q?
16:26:37 [jar]
q+ danc
16:26:40 [jar]
q+ jar
16:26:46 [masinter]
... even if 1st class support for application/xhtml+xml
16:28:31 [masinter]
ht: as long as the columns are full of "maybe this or maybe that", it isn't helpful to push people to make their minds up
16:28:33 [masinter]
q?
16:28:50 [noahm]
q?
16:29:16 [masinter]
(chart only partly filled out... longtail check, check, check, x
16:29:23 [masinter]
... x check x check
16:29:32 [masinter]
i.e. has only ? under MS proposal
16:29:37 [noahm]
ack danc
16:29:47 [masinter]
danc: queue slot was to solicit people to write a blog entry
16:29:49 [timbl_]
q+ to point out that reusing exstig xmlns syntax has great advantages
16:30:00 [noahm]
ack jar
16:30:12 [DanC_]
yeah, timbl, I meant to make a row for that; neglected to
16:30:38 [masinter]
jar: there's enough in the chart to take us from Tim's original proposal that we endorse the MS proposal, but I think this takes us a step further. We could say "we like the MS proposal insofar as it does X, Y and Z"
16:31:01 [masinter]
noah: (will drain queue, and see where we are)
16:31:07 [masinter]
q?
16:31:12 [masinter]
ack next
16:31:13 [Zakim]
timbl_, you wanted to point out that reusing exstig xmlns syntax has great advantages
16:32:32 [masinter]
timbl: Reusing existing syntax, not inventing new stuff. Inventing new stuff is a hurdle. If it's a good thing to do. Just being able to say: for a given MIME type, have a default namespace.
16:32:41 [masinter]
danc: that's the state of the art
16:32:58 [masinter]
timbl: XML tools don't have an easy way of taking that into account
16:33:06 [noahm]
zakim, close the queue
16:33:06 [Zakim]
ok, noahm, the speaker queue is closed
16:33:09 [noahm]
q?
16:33:15 [masinter]
timbl: This would be a relief in other cases
16:33:31 [DanC_]
(ah yes, tim; in particular, authors have to put the xmlns="...xhtml" for XML tool interop.)
16:33:52 [masinter]
ht: i've just added 3 new rows to the table: reuses existing syntax. X for all but MS
16:34:11 [masinter]
ht: ... simplifies the syntax and simplifies the DOM
16:34:27 [masinter]
timbl: I asked "Is the DOM the same?" and you said "Yes"
16:34:41 [masinter]
ht: the HTML community *wants* the DOM to be simplified
16:35:14 [masinter]
ht: currently standing HTML tick on "Simplifies the DOM" is x for everything except for standing HTML5
16:36:02 [masinter]
... 'simplify the syntax' is all check except for MS
16:36:19 [DanC_]
(still no takers on blogging this table? sigh. oh well.)
16:38:46 [DanC_]
action-357: try to include the requirements table
16:38:46 [trackbot]
ACTION-357 Elaborate the DPD proposal to address comments from #xmlnames and tag f2f discussion of 2009-12-10, particularly wrt integration with XML specs and wrt motivation, due 2010-01-08 notes added
16:39:10 [plh]
16:39:17 [plh]
HTML 5: The Markup Language
16:39:54 [ht]
There are 3 docs: Hixie's, Mike Smith's and Lachlan Hunt's
16:40:19 [plh]
q+
16:40:21 [DanC_]
q+ to note the call for proposals with deadline on this issue in the HTML WG, which looks good to me, provided H:TML really gets delivered
16:40:25 [masinter]
topic: html5 review
16:40:36 [plh]
zakim, reopen the queue
16:40:36 [Zakim]
ok, plh, the speaker queue is open
16:41:45 [masinter]
(looking for normative language reference spec)
16:42:16 [noahm]
q+ to talk about hixie's spec
16:42:22 [ht]
16:42:58 [masinter]
q+ to talk about DOM API call being documented by normative algorithms
16:43:03 [masinter]
has a different date
16:43:21 [DanC_]
(editor of html-author is lachlan, I think; he's carrying 0 actions.
)
16:43:35 [masinter]
plh: the group doesn't want to have a document that is normative
16:43:49 [masinter]
ht: I think we lost the argument to split the spec?
16:44:27 [ht]
s/spec?/spec into a language spec. and a behaviour spec./
16:44:48 [masinter]
noah: point of clarification? Is this document going to progress
16:44:59 [masinter]
plh: for the moment, it doesn't officially exist
16:45:22 [masinter]
plh: if the working group decided to do that, it would likely be normative
16:45:51 [masinter]
(review of Maciej message of 08 Dec 2009 15:55:20)
16:45:59 [masinter]
q?
16:46:36 [DanC_]
q+ to note two targets: (a) more traditional language spec (b) guide for authors. We seem to have missed HT's interest in (b). html-author is dated March 2009 and its editor, lachlan, is carrying no actions
16:46:42 [masinter]
noah: would like he TAG to assess this. I skimmed this: far better than my worst fears, considerably worse than what I would hope for
16:46:48 [masinter]
q?
16:46:51 [masinter]
ack noahm
16:46:51 [Zakim]
noahm, you wanted to talk about hixie's spec
16:46:54 [plh]
s/is normative/is normative, since this would create a high risk of conflicts between the documents/
16:47:04 [noahm]
q?
16:47:06 [masinter]
ht: this doesn't come close to what I want
16:47:13 [masinter]
ht: there is no grammar. I want a grammar.
16:47:35 [jar]
q+ jar to say the issue is how to evaluate the spec (speaks to openness of web). having 2nd spec that tracks is one way, modularizing the spec is a 2nd way, having a grammar is a 3rd...
16:47:58 [masinter]
noah: I don't elevate the lack of a grammar to... (absolutely necessary)
16:48:01 [DanC_]
ack next
16:48:02 [Zakim]
masinter, you wanted to talk about DOM API call being documented by normative algorithms
16:48:49 [noahm]
FWIW, my criterion for success is not "does it use formal grammars", though I think they
16:49:19 [ht]
what is URI for "authoring view" of Hixie's draft
16:49:21 [ht]
?
16:49:48 .
16:49:59 )
16:50:42 [noahm]
LMM: Reminds us of the point he's made before, that there are things stated algorithmically (e.g. interpretation of image width/height) that should be done more declaratively.
16:50:52 [noahm]
ack next
16:50:53 [Zakim]
DanC_, you wanted to note two targets: (a) more traditional language spec (b) guide for authors. We seem to have missed HT's interest in (b). html-author is dated March 2009 and
16:50:55 [Zakim]
... its editor, lachlan, is carrying no actions
16:51:02 [jar]
(danc, ACL2 is for proofs. Larry says he's missing the theorems.)
16:51:26 [DanC_]
(ACL2 does plenty of stuff with theorems; I don't understand your point)
16:51:39 [noahm]
From email from Ian Hickson:
16:51:45 [noahm]
I have now made the three versions available:
16:51:45 [noahm]
16:51:45 [noahm]
16:51:45 [noahm]
16:52:09 [masinter]
the point was: what are the invariants that a reasonable programmer or generator of programs can assume? Many of these are embedded deeply within algorithms presented for implementors, that cannot be inferred or extracted by any textual processing, because it's not written down anywhere.
16:52:53 [noahm]
I am interested in the style=author one as a best approximation to a language spec, because it's the only one we're likely to get that's normative.
16:53:01 [masinter]
ht: I was interested in the document, because I thought it was actively being worked on. But to be clear, i'm not interested in an authoring spec, I'm interested in a language spec.
16:53:11 [noahm]
I do regret that it's advertised as an authoring spec, because I agree that a language spec is the higher priority.
16:53:30 [masinter]
q?
16:53:30 [DanC_]
ack next
16:53:30 [noahm]
Still, it may do the job, and my question is: does it, and if not, would some tuning get it there.
16:53:32 [ht]
q+ to explain why I find
unhelpful
16:53:32 [Zakim]
jar, you wanted to say the issue is how to evaluate the spec (speaks to openness of web). having 2nd spec that tracks is one way, modularizing the spec is a 2nd way, having a
16:53:34 [Zakim]
... grammar is a 3rd...
16:53:58 [noahm]
q+ to say why I find
helpful
16:54:15 [masinter]
jar: this may be obvious: there's some objective to be able to approach the spec. This thing is just too big for that. There are multiple for making this tractable.
16:54:29 [masinter]
q+ to talk about getting away from the need for always-on updates to HTML
16:54:57 [masinter]
jar: you want to know what the spec does what it's supposed to do, and having it be so big is a problem. My message is to keep your eye on the ball.
16:55:00 [masinter]
ack ht
16:55:00 [Zakim]
ht, you wanted to explain why I find
unhelpful
16:55:04 [DanC_]
(I think mutliple normative specs is _good_ for QA, but when I gave that opinion in the HTML WG, it was clear hardly anybody else in the WG agrees.)
16:55:20 [noahm]
ack next
16:55:21 [masinter]
ht: i would like to use the last part to ask PLH his view.
16:55:22 [Zakim]
noahm, you wanted to say why I find
helpful
16:55:44 [DanC_]
(e.g. having the OWL language spec and the test suite both normative; if they conflict, there's a bug, and I'm not prepared to say, in advance, where the bug is.)
16:56:28 [masinter]
noahm: I find it really helpful. To me the thing that makes it valuable is that it would be worthwhile for us to take what was offered and read it with some care.
16:56:36 [DanC_]
q+
16:56:42 [DanC_]
q+ to respond re reading the author view
16:56:44 [johnk]
q+ to ask who are we trying to help here?
16:56:48 [masinter]
... if the answers are in some ways promising, that would be good.
16:57:05 [noahm]
ack masinter
16:57:05 [Zakim]
masinter, you wanted to talk about getting away from the need for always-on updates to HTML
16:57:37 [noahm]
Some was lost in scribing what I said above, so let me clarify:
16:58:31 [noahm]
I think the style=author draft, which I've skimmed but not read in full detail, is valuable in several ways, but especially because it is being offered as normative, and well synced with the other variants of the spec.
16:58:32 [jar]
lm: reiterating applicability statement idea raised earlier. 2 docs, one with undated references, another (the a.s.) with dated references "the way things are in 2010"
16:59:13 [jar]
lm: the goal is to avoid the need to publish new specs too frequently
16:59:35 .
17:00:06 [masinter]
danc: authoring spec engaged me to some degree, but didn't find it compelling to spend more time on it
17:00:32 [masinter]
noah: is there something you could say?
17:01:04 [jar]
does it matter whether it engages anyone? the OWL WG basically said no, the non-normative docs can be engaging
17:01:08 [noahm]
DC: Well, hello world is in section 8. Oops, nope, I guess I fixed that.
17:01:26 [jar]
q?
17:01:27 [noahm]
q?
17:01:28 [masinter]
danc: the 'hello world' example *was* in section 8. Previously, it was hard to tell whether there was something that was a constraint on documents vs. a constraint on implementation
17:01:40 [masinter]
... that seems to have gotten better.
17:02:10 [masinter]
ack next
17:02:17 [Zakim]
DanC_, you wanted to respond re reading the author view
17:02:21 [noahm]
q+ jar
17:02:32 [ht]
Beware that if you follow TOC links from
you _lose_ the parameter, and have to re-enter it by hand
17:02:32 [masinter]
jk: who are we helping with respect to getting a grammar? Who cares?
17:03:17 [masinter]
... Hixie has done something toward satisfying a goal, we don't know if it is close to satisfying our goal
17:03:23 [plh]
q+
17:03:28 [masinter]
... maybe this is our chance of getting a spec that's normative
17:03:29 we should give.
17:03:39 [masinter]
q+ to talk about goals
17:03:46 [noahm]
ack next
17:03:47 [Zakim]
johnk, you wanted to ask who are we trying to help here?
17:03:48 [noahm]
ack next
17:04:59 [DanC_]
I'm not prepared to give feedback on behalf of the design community, Noah; look at my web pages; they're design jokes, at best. I've encouraged the design community to comment for themselves, and had mixed success.
17:05:05 [masinter]
jar: I think it is a threat, if you have standards that are hard to understand, that's a threat to openness
17:05:07 [masinter]
q?
17:05:26 [noahm]
ack plh
17:05:50 [ht]
HST absolutely agrees with PLH -- W3C writes specs for implementors
17:06:01 [ht]
.. but implementors need language specs, not algorithms
17:06:04 [masinter]
plh: with the working group, who are we writing the spec for? For the implementors? The users can buy books. The implementors disagree.
17:06:21 [masinter]
danc: there are lots of examples for users in the spec, though, not just for implementors.
17:06:51 [masinter]
plh: given the resources, though, most of them spend their time
17:06:52 [noahm]
I strongly disagree. Books are very helpful, but not normative. There are architectural, and thus practical, benefits to having a rigorous, precise specification for a language, a spec that's not unnecessarily tangled with specs for other things.
17:07:00 [masinter]
plh: there's a RELAXNG schema
17:07:06 [masinter]
ht: it has no authority
17:07:25 [ht]
plh: The WG might adopt it as a WD
17:07:30 [ht]
hst: That would be great
17:07:36 [noahm]
LM: I want to support implementors of things other than browsers. Transformers, editors, etc.
17:07:56 .)
17:08:01 [ht]
masinter +1
17:08:37 [johnk]
LM: HTML for ATOM, HTML for email
17:09:26 [masinter]
plh: the chairs would like to move HTML5 to last call soon. pick your battles. Look at the long list of issues the WG already has, are there any that don't have a change proposal, consider making a proposal for those.
17:10:16 [masinter]
noahm: would like to get someone on TAG to review the table (and maybe things that have fallen off the table), would like to use that to help prioritize
17:10:29 [masinter]
danc: I already did this before and did it again last night
17:11:34 [masinter]
danc: there is one
17:13:05 [DanC_]
ACTION Noah schedule discussion of 'usage of 'resource' vs 'representation' in HTML 5, CSS, HTML 4, SVG, ...' [note follow-up discussion in www-archive]
17:13:05 [trackbot]
Created ACTION-358 - Schedule discussion of 'usage of 'resource' vs 'representation' in HTML 5, CSS, HTML 4, SVG, ...' [note follow-up discussion in www-archive] [on Noah Mendelsohn - due 2009-12-17].
17:13:28 [masinter]
(review of HTML open issues was only against 'things to be closed soon')
17:13:34 [ht]
DanC, I agree that user needs must be addressed by the _designs_ which WGs produce, but that that is _not_ the leading priority for the specs which communicate those designs
17:14:11 [masinter]
noah: we did have this discussion of authoring. Would be helpful to... (?)
17:15:40 [masinter]
noah: proposal: (review of Maciej message of 08 Dec 2009 15:55:20) We do not have a uniform opinion of how much this meets needs, but we think this is ... positive.
17:15:41 [DanC_]
PROPOSED: to endorse the proposed disposition of HTML WG issue-59 in
, i.e. the class=author view and the informative reference guide
17:16:01 [masinter]
ht: message proposes closes this issue. We should say: don't do this, we're not happy.
17:16:36 [DanC_]
I gather ht doesn't find my proposal appealing
17:16:40 [masinter]
ht: wants the TAG to ask for a language spec
17:19:08 [DanC_]
q+
17:19:26 [masinter]
lm: I want the HTML working group to agree that they will review the resulting document and come to consensus about its adequacy, not just to do so as a political move to meet someone else's pro-forma requirement
17:20:31 [masinter]
ht: Maciej's message proposes to adopt it as a non-normative WG proposal
17:20:40 [masinter]
(discussion of whether the doc supports RelaxNG grammar)
17:21:19 [DanC_]
PROPOSED: to endorse the proposed disposition of HTML WG issue-59 in
, i.e. the class=author view and the informative reference guide, provided the relaxng is appended to the informative reference guide
17:23:04 [ht]
PROPOSED: to endorse the proposed disposition of HTML WG issue-59 in
, i.e. the class=author view and the informative reference guide, provided the relaxng is appended to the informative reference guide, which will be published as a Working Draft and taken forward
17:23:53 [masinter]
noahm: and maintained as the HTML language evolves?
17:24:04 [masinter]
(wordsmithing of response)
17:24:46 [ht]
PROPOSED: to endorse the proposed disposition of HTML WG issue-59 in
, i.e. the class=author view and the informative reference guide, provided the relaxng is appended to the informative reference guide, which will be published as a Working Draft and maintained
17:25:47
17:26:24 [plh]
I suggest s/to Last Call/through Last Call/
17:26:41 [masinter]
so RESOLVED
17:26:57 [ht]
s/taken to last call/taken through Last Call/
17:27:02 [masinter]
RESOLVED: endorse the proposed disposition of HTML WG issue-59 in
, i.e. the class=author view and the informative reference guide, provided the relaxng is appended to the informative reference guide, which will be published as a Working Draft and taken to Last Call
17:27:38 [masinter]
action: Noah to communicate TAG resolution to HTML WG
17:27:38 [trackbot]
Created ACTION-359 - Communicate TAG resolution to HTML WG [on Noah Mendelsohn - due 2009-12-17].
17:32:24 [noahm]
ADJOURNED FOR LUNCH UNTIL 13:30
17:40:03 [raman]
raman has joined #tagmem
17:40:22 [raman]
ping me when you guys are back from lunch
17:55:09 [noahm]
Will do. Plan is to return 1:30 PM our time, 10:30 yours.
17:55:31 [noahm]
I will take a crack at munging the agenda to reflect reality shortly.
18:00:30 [raman]
calling
18:02:00 [timbl_]
Raman, we restart at half past
18:02:01 [raman]
will call 10:30
18:02:04 [noahm]
Thank you.
18:10:26 [jar]
jar has joined #tagmem
18:21:19 [timbl_]
timbl_ has joined #tagmem
18:36:22 [timbl_]
timbl_ has joined #tagmem
18:37:42 [noah]
noah has joined #tagmem
18:37:45 [DanC_]
scribenick: DanC_
18:38:43 [DanC_]
Topic: Admin
18:39:14 [DanC_]
ACTION John: clean up TAG ftf minutes 8 Dec
18:39:15 [trackbot]
Created ACTION-360 - Clean up TAG ftf minutes 8 Dec [on John Kemp - due 2009-12-17].
18:39:26 [DanC_]
ACTION Henry: clean up TAG ftf minutes 9 Dec
18:39:26 [trackbot]
Created ACTION-361 - Clean up TAG ftf minutes 9 Dec [on Henry S. Thompson - due 2009-12-17].
18:39:27 [noah]
Raman, we are starting, and we are dialed in
18:39:53 [DanC_]
ACTION Dan: clean up TAG ftf minutes 10 Dec, and either wrap up the 3 days or get Noah to do it
18:39:53 [trackbot]
Created ACTION-362 - Clean up TAG ftf minutes 10 Dec, and either wrap up the 3 days or get Noah to do it [on Dan Connolly - due 2009-12-17].
18:40:00 [DanC_]
NM reviews agenda...
18:40:22 [ht]
John, <link id="xf" rel="prefix" is already allowed !
18:40:52 [raman]
something is different in the room, audio is awful, lots of echo
18:41:14 [DanC_]
echo? bummer.
18:42:03 [DanC_]
HT: I do have something re references... though I'm OK if that goes to a telcon
18:43:21 [DanC_]
NM accepts the agenda request; commits Revision: 1.31
18:43:54 [DanC_]
raman? audio better?
18:44:22 [noah]
Raman, I have moved the mic, and will dial again if necessary. Was good this morning. Can't hear you at all.
18:44:25 [noah]
zakim, who is here?
18:44:25 [Zakim]
sorry, noah, I don't know what conference this is
18:44:26 [Zakim]
On IRC I see noah, timbl_, jar, raman, johnk, DanC_, Zakim, RRSAgent, masinter, ht, DanC, trackbot
18:44:31 [DanC_]
Zakim, this is tag
18:44:31 [Zakim]
ok, DanC_; that matches TAG_f2f()8:30AM
18:44:34 [noah]
zakim, who is here?
18:44:34 [Zakim]
On the phone I see [MIT-G449], Raman
18:44:36 [Zakim]
On IRC I see noah, timbl_, jar, raman, johnk, DanC_, Zakim, RRSAgent, masinter, ht, DanC, trackbot
18:45:04 [DanC_]
Topic: Metadata Architecture: ISSUE-62 (UniformAccessToMetadata-62): Uniform Access to Metadata
18:45:23 [DanC_]
ACTION-281?
18:45:23 [trackbot]
ACTION-281 -- Ashok Malhotra to keep an eye on progress of link header draft, report to TAG, warn us of problems (ISSUE-62) -- due 2009-11-13 -- PENDINGREVIEW
18:45:23 [trackbot]
18:46:25 [DanC_]
AM: we're tracking 4 drafts... linking, well-known, host-meta, XRDD... I think one got updated since I sent mail...
18:46:42 [noah]
Raman, please ping us in IRC when we have your attention again. Thank you.
18:47:04 [DanC_]
AM: I saw comments from Tim and Dan... the authors have seen those
18:47:07 [noah]
DC: I had a concern about the registration and Mark Nottingham fixed it.
18:47:26 [DanC_]
AM: these are 3 mechanisms for attaching metadata
18:47:39 [DanC_]
AM: are these enough? do we need more?
18:47:52 [DanC_]
... and JAR said something about an iTunes-like mechanism...
18:48:16 [DanC_]
JAR: well... maybe the issue name should be changed... it suggests there will be a limited number of ways to access metadata...
18:48:51 [DanC_]
... these 3 mechanisms are about 1st-party metadata. in the [academic] metadata world, that's the least valuable, but in other cases, it's useful, especially if it's all you've got
18:49:12 [DanC_]
JAR: so something like "uniform access to 1st party metadata"; this isn't metadata in general
18:49:34 [masinter]
q?
18:49:58 [DanC_]
NM: this is metadata that the 1st party helps you find
18:50:03 [Ashok]
Ashok has joined #tagmem
18:50:06 [DanC_]
JAR: that link itself is metadata
18:50:31 [DanC_]
q+
18:51:10 [DanC_]
LMM: if you include the pre-production and production workflow, [oops; I lost the train of thought]... photo metadata...
18:51:28 [DanC_]
... the camera is the 1st party...
18:51:40 [jar]
jar: I agree... I may need to adjust my terminology
18:52:44 [DanC_]
... the person who takes the photo and edits it is the 2nd party... and the next person in the workflow is 3rd, copyright guy is 4th party... or there's a lot of 3rd parties
18:53:04 [DanC_]
DanC: from the perspective of the link-header draft, all those are, in aggregate, the 1st party
18:53:16 [DanC_]
LMM: no, if you look in the photo, you can see the audit trail
18:53:18 [DanC_]
DanC: ah.
18:53:53 [DanC_]
LMM: and it goes on from there... flickr taggers, commenters, etc.
18:54:11 [DanC_]
JK: doesn't that means that the metadata inside the data?
18:54:19 [DanC_]
LMM: it helps in the production workflow...
18:54:48 [DanC_]
(I think the way I scribed JK makes the referent of "that" misleading.)
18:55:07 [DanC_]
... but flickr tags and comments, probably not
18:55:16 [timbl_]
q?
18:55:27 [DanC_]
ack masinter
18:55:27 [Zakim]
masinter, you wanted to talk about goals
18:55:52 [DanC_]
TBL: in the adobe tools, can you set the trail of custody? [something like that]
18:56:02 [DanC_]
LMM: in varying degrees, yes
18:56:12 [DanC_]
TBL: when adobe tools get content from the web, can they recover the trail?
18:56:14 [DanC_]
LMM: I don't know
18:56:25 [DanC_]
TBL: the metadat trust is [scribe falls behind]
18:56:42 [jar]
q+ jar to suggest "server provided links" or "server provided metadata"
18:56:52 [DanC_]
[discussion between TBL and LMM exceeds scribe bandwidth]
18:56:56 [noah]
q?
18:58:37 [DanC_]
...
18:59:11 [DanC_]
LMM: in Seybold community, I learned the industry uses a variety of mechanisms to send images around... often not compressed...
18:59:24 [jar]
I want to know what problem we're working on now.
18:59:31 [DanC_]
TBL: I'm interested in "this is/was
http://....
" .
18:59:45 [DanC_]
LMM: the workflow uses guiids rather than locations; these things move around too much
18:59:47 [masinter]
the locations weren't normative
19:00:03 [DanC_]
ack me
19:00:13 [noah]
q+ ashok
19:00:43 [masinter]
I guess the point is that first-party metadata is often embedded, and that the Link header is better thought of as "third-party metadata" where the third-party is the publishing web site
19:01:56 [jar]
danc: Host-meta, powder, EARL - I would only want to write that software once (see public email)
19:02:56 [DanC_]
DanC: and I have a concern about not using .well-known unless it's merited in ways that Roy emphasized
19:03:31 [DanC_]
JAR: [who]'s concerns increases my desire to change the name of the issue... "server provided metadata"?
19:03:46 [timbl_]
Maybe we should be charging $10M for an entry in "well-known" to express the cost to the community of each one, clients having to check different places.
19:04:44 [DanC_]
(I'm happy for the issue shepherd to change the issue name whenever they see fit; I trust them to consult the TAG as appropriate)
19:04:55 .
19:05:32 [masinter]
issue-62?
19:05:32 [trackbot]
ISSUE-62 -- Uniform Access to Metadata -- OPEN
19:05:32 [trackbot]
19:06:18 [DanC_]
issue-62?
19:06:18 [trackbot]
ISSUE-62 -- Uniform Access to Metadata -- OPEN
19:06:18 [trackbot]
19:06:24 [DanC_]
issue-62?
19:06:24 [trackbot]
ISSUE-62 -- Uniform Access to Server-provided Metadata -- OPEN
19:06:24 [trackbot]
19:06:41 [noah]
Note that we just changed the name of the issue, as echoed above.
19:06:45 [masinter]
issue-63?
19:06:45 [trackbot]
ISSUE-63 -- Metadata Architecture for the Web -- OPEN
19:06:45 [trackbot]
19:06:56 [DanC_]
AM: do we need another issue for the rest?
19:07:09 [DanC_]
JAR: we have the broader issue; issue-63
19:07:53 [jar]
ack jar
19:07:53 [Zakim]
jar, you wanted to suggest "server provided links" or "server provided metadata"
19:08:10 [noah]
q?
19:08:14 [DanC_]
ack ashok
19:09:01 [jar]
These RFCs are going to be final soon. Very narrow window to have influence.
19:09:07 [DanC_]
q+
19:09:12 [noah]
q+ to ask questions from chair
19:09:17 [DanC_]
q- later
19:09:51 [DanC_]
AM: again, do we need more mechanism? or fewer?
19:10:00 [DanC_]
DanC: I'd like to see fewer
19:10:21 [DanC_]
JAR: these specs are nearing deployment
19:10:30 [masinter]
q+ to note that there are lots of other requirements and to diminish the importance of IETF proposed standards
19:10:33 [noah]
ack next
19:10:34 [Zakim]
noah, you wanted to ask questions from chair
19:10:35 [timbl_]
q+
19:10:46 [DanC_]
DanC: do you have any critical concerns? are you happy with the specs, JAR?
19:10:50 [DanC_]
JAR: yes, I'm happy
19:11:30 [DanC_]
q+ to ask about use cases that are market drivers
19:11:49 [noah]
q?
19:11:52 [DanC_]
ack masinter
19:11:52 [Zakim]
masinter, you wanted to note that there are lots of other requirements and to diminish the importance of IETF proposed standards
19:11:53 [noah]
ack masinter
19:11:54 [timbl_]
q+ to say, well it would be better if they were all RDF of course. Are we goingto do nothing about that?
19:12:35 [DanC_]
LMM: are the applicability of these draft narrow enough that other cases are ruled out? [?]
19:12:54 [timbl_]
q?
19:12:55 [DanC_]
... I don't think publication of these as Proposed Standard will get in the way if something else is more appropriate
19:12:58 [DanC_]
JAR: well, it'll compete
19:13:55 [DanC_]
... well, doesn't compete with mechanisms for other sources of metadata
19:14:13 [jar]
it will compete in the very narrow in which it applies. won't compete with ways of getting metadata *from other sources*
19:14:17 [noah]
q?
19:14:29 [DanC_]
LMM: my remaining concern is: when more than one of these mechanisms provides info, what about priority?
19:15:02 [DanC_]
JAR: thie "Web Linking" explicitly says "this is not authoritative; apps have to come up with their own trust model"
19:15:41 [johnk]
q+ to note that Link header was originally specifically about representations that could not contain <link> elements
19:15:48 [DanC_]
LMM: it's not a matter of trust, it's a matter of intent. e.g. if I write copyright in both the Link header and in the content and they're different, which do I mean? both?
19:15:50 [DanC_]
TBL: that's a bug
19:16:11 [DanC_]
TBL: i.e. the web site is buggy [not the link header spec]
19:16:17 [jar]
there's no such thing as overriding a copyright statement (legally)...
19:17:00 [DanC_]
LMM: I don't like the "then it's a bug and we don't say which"; I prefer priorities
19:17:08 [noah]
q?
19:17:40 [DanC_]
TBL: priorities allow people to write incorrect things that get obscured due to priorieites; then they get surfaced when the document moves
19:17:48 [DanC_]
ack danc
19:17:48 [Zakim]
DanC_, you wanted to ask about use cases that are market drivers
19:18:15 [timbl_]
A language should ays "if you write this, then it means *this*".
19:18:25 [jar]
the resource and the server are distinct principals with different interests. metadata is statements of fact. thus disagreements are inherent and unresolvable outside of a trust model
19:18:25 [timbl_]
Not "it means this unless it is overridden...".
19:18:51 [noah]
DC: The specs may well come out, but it would be interesting to remind ourselves what the market drivers are for the specs we're discussing here.
19:19:03 [noah]
DC: Anyone know what the drivers are, e.g., for host meta?
19:19:10 [masinter]
points to
for dealing with conflicting embedded metadata
19:19:23 [noah]
AM: It says it's for where the host controls.
19:19:30 [noah]
DC: But who's going to make money.
19:19:45 [noah]
Falling behind scribing johnk....
19:20:11 [masinter]
q+ to talk to the MWG document dealing with conflicting metadata
19:20:17 [DanC_]
JK: I think the market-driving use case is URI templates ... advertising.
19:21:06 [DanC_]
JK: e.g. "if you want to look up a person whose profile is on my site, here's the URI template to plug the username into". and having lots of users leads to advertising revenue.
19:21:21 [DanC_]
... e.g. google, yahoo, etc.
19:21:27 [Ashok]
q+
19:21:30 [noah]
ack next
19:21:31 [Zakim]
timbl_, you wanted to say, well it would be better if they were all RDF of course. Are we goingto do nothing about that?
19:21:58 [masinter]
from
19:22:10 [DanC_]
TBL: this XRD format seems to overlap significantly with RDF... how much RDF is there out there?
19:22:13 [DanC_]
... a lot.
19:22:26 [DanC_]
... and we're pushing linked data...
19:22:40 [DanC_]
... linking host meta into the linked data world seems helpful
19:23:21 [noah]
The XRD thing is already deployed, right?
19:23:21 [DanC_]
JAR: use GRDDL?
19:23:54 [DanC_]
TBL: but I can't use an RDF serializer to write XRD
19:24:01 [DanC_]
JAR: XRD is very simple
19:24:11 [DanC_]
TBL: I can't write arbitrary RDF into XRD
19:24:30 [DanC_]
JAR: aside from bnodes and literals, you can; i.e. arbitrary uri triples
19:25:14 [DanC_]
JK: ... web finger ...
19:26:15 [DanC_]
(If I were going to push on something, I'd push RDFa rather than RDF/XML)
19:26:28 [masinter]
q?
19:27:09 [noah]
ack next
19:27:11 [Zakim]
johnk, you wanted to note that Link header was originally specifically about representations that could not contain <link> elements
19:27:15 [jar]
q?
19:28:04 [DanC_]
JK: using <link> for formats that can't express links is like [something larry was talking about]
19:28:11 [jar]
q+ to answer larry regarding priority between sources (i will just say what i already entered in irc)
19:28:59 [noah]
ack next
19:29:00 [Zakim]
masinter, you wanted to talk to the MWG document dealing with conflicting metadata
19:29:05 [masinter]
points to
for dealing with conflicting embedded metadata
19:29:39 [noah]
NM: This reinforces Tim's point. If the use case in mind is where there's no possible duplication, then duplication with conflict should be an error, not resolved with priority.
19:29:43 [DanC_]
LMM: even when the metadata is embedded, you can have multiple kinds of metadata... this points to the practical issue of...
19:30:00 [DanC_]
... what if you have EXIF, [something else], and conflicts, and how to manage...
19:30:24 [timbl_]
q+
19:30:35 [DanC_]
... so I think the "conflicting metadata is a bug; we're not telling what to do" doesn't suffice...
19:30:55 [DanC_]
... I suggest to say that it's not an error... providing an override mechanism is important
19:31:09 [noah]
ack jar
19:31:09 [Zakim]
jar, you wanted to answer larry regarding priority between sources (i will just say what i already entered in irc)
19:32:10 [masinter]
q+ to disagree: metadata is always an issue of opinion, not a theory of fact
19:32:17 [noah]
ack timbl_
19:32:33 [DanC_]
JAR: metadata is typically a statement of fact. [LMM: no]. sometimes the server is right; sometimes the resource is right; each consumer has to decide who to believe
19:32:50 [DanC_]
q+
19:33:27 [noah]
ack Ashok
19:33:33 [DanC_]
q+ to speak to expressiveness of override mechanism
19:33:38 [johnk]
In response to the question "is XRD deployed" I mentioned WebFinger (see
) which I believe may already be deployed
19:34:21 [masinter]
I don't want to say "who is right and who is wrong". I just am asking that the Link header be expanded to alow the server to be clear about whether the intent of the server is to override, supplant, or replace embedded metadata.
19:34:27 [noah]
DC: I said host meta is one too many because it duplicates what RDF already provides
19:34:31 [noah]
ack masinter
19:34:31 [Zakim]
masinter, you wanted to disagree: metadata is always an issue of opinion, not a theory of fact
19:34:42 [noah]
JAR: It's a putative fact
19:34:53 [DanC_]
AM: when I asked whether this is the right number of mechanism I got sort of a yes from LMM and JAR and a No from Dan... elaborate?
19:35:17 [johnk]
JK: regarding the Link header, I mentioned that the original use-case (IIRC!) was specifically for cases where an HTTP entity-body could not contain "links" (for example, text/plain)
19:35:22 [noah]
LM: I'm not looking to settle who's right, I'm looking for priority mechanisms.
19:35:31 [noah]
q?
19:35:34 [DanC_]
DanC: I think Host-Meta overlaps with existing mechanisms: POWDER. so we've got more mechanisms than I'd like to see. [don't mean to be emphatic about which of POWDER or Host-Meta shold survive]
19:36:08 [noah]
Interesting Dan, I thought some of what you wanted was an RDF answer (or maybe I'm channeling Tim through you)
19:36:20 [noah]
ack DanC_
19:36:20 [Zakim]
DanC_, you wanted to speak to expressiveness of override mechanism
19:36:47 [jar]
"The server believes this information to be more trustworthy than what the resource says." or "The server that what the resource says is more likely to be right than what it says."
19:36:49 [noah]
DC: The client can have all sorts of policies, but it's less expressive if you don't let the sender express a preference.
19:37:33 [DanC_]
TBL: architecturally, the HTTP header overrides the content... but in practical cases, people want their content to override the server config too.
19:38:33 [DanC_]
JAR: I'd say mnot and Eran would say: it's the responsibility of what's pointed to by Link: to have this override mechanism.
19:38:59 .
19:39:12 [DanC_]
NM: we can always come back to this...
19:39:21 [DanC_]
JAR: no; there's a market window...
19:39:29 [DanC_]
DC: does anybody know timing of large deployments?
19:39:48 [DanC_]
JK: I think webfinger is deployed at scale, using [Host-Meta?]
19:40:28 [DanC_]
q+ to express obligation to connect with SemWeb CG
19:41:08 [DanC_]
HT: uniform access has come back into this... harks back to XRI and [missed]...
19:43:25 [DanC_]
HT: the energy currently is going into how to provide metadata that addresses the uniform access problem...
19:43:45 [DanC_]
... the good news is that although there are what might look like 3 competing proposals, actually they play nice together
19:43:53 [DanC_]
... and there's a story about how
19:44:05 [DanC_]
HT: that's what I heard.
19:44:47 [noah]
DC: As team contact, I feel that doing nothing isn't good.
19:45:08 [noah]
DC: I think we need to connect with the Sem Web coordination group.
19:45:24 [noah]
DC: But....reluctant to add to my own queue
19:45:42 [noah]
JAR: I could approach them but have been discouraged [scribe notes that parses a couple of ways...not sure which intended]
19:46:15 [Ashok]
Webfinger:
19:46:45 [noah]
DC: What I have in mind is along the lines of going to coord group and say: Hey, this is about to happen without RDF. Problem?
19:48:05 [DanC_]
. ACTION: Jonathan inform SemWeb CG about market developments around webfinger and metadata access ...
19:49:10 [DanC_]
. ACTION: Jonathan inform SemWeb CG about market developments around webfinger and metadata access, and investigate relationship to RDFa and linked data
19:49:22 [DanC_]
ACTION: Jonathan inform SemWeb CG about market developments around webfinger and metadata access, and investigate relationship to RDFa and linked data
19:49:22 [trackbot]
Created ACTION-363 - Inform SemWeb CG about market developments around webfinger and metadata access, and investigate relationship to RDFa and linked data [on Jonathan Rees - due 2009-12-17].
19:49:57 [timbl_]
19:50:53 [jar]
Last call ended for .well-known and Link:
19:50:55 [masinter]
the TAG could ask the editor (Mark) to note open issues: use of RDF vs. other metadata representations, and whether Link: overrides, supplants, or defaults embedded metadata.
19:51:08 [raman]
what time is you rbreak? my mike may be muted
19:51:52 [Zakim]
-Raman
19:54:41 [masinter]
the discussion has been useful, even if we don't act further
19:55:12 [DanC_]
close action-281
19:55:12 [trackbot]
ACTION-281 Keep an eye on progress of link header draft, report to TAG, warn us of problems (ISSUE-62) closed
19:55:19 [noah]
Supposedly now until 3:15, but we're struggling to
19:55:24 [DanC_]
close action-336
19:55:24 [trackbot]
ACTION-336 Prep Metadata Architecture for Dec f2f closed
19:56:15 [noah]
WE ARE ON BREAK UNTIL 15:20 US EST
20:21:43 [DanC_]
Topic: (xmlFunctions-34): XML Transformation and composability (e.g., XSLT,XInclude, Encryption)
20:23:00 [DanC_]
DanC: HT notified us of a default processing model draft in the XProc WG
20:23:34 [masinter]
(back from break)
20:24:48 [ht]
20:25:11 [DanC_]
DanC: any processing model that does Xinclude shouldn't be "_the_ default_" ...
20:25:34 [DanC_]
... previously, HT seemed sympathetic
20:27:11 [noah]
(some metadiscussion on whether editors of this are obligated to listen to input before formal drafts available. Editor warns that lack of sleep will lead to forgetfulness anyway.)
20:27:42 [DanC_]
... I think the way to make it clear that this is not _the_ default processing model is to include another one...
20:27:54 [noah]
DC: Earlier, I said "Default Processing Model" isn't the right title. Henry, you seemed sympathetic. Are you still.
20:28:03 [noah]
HT: Um, loses some value.
20:28:13 [masinter]
q+ to ask whether this belongs with the application/xml media type & reregistration of it
20:28:21 [DanC_]
... the trivial one: just use the bytes you got
20:28:22 [noah]
HT: Lots of people should point to this.
20:28:27 [noah]
DC: So you do want to be THE model.
20:28:29 [noah]
HT: Yes.
20:28:35 [Ashok]
Ashok has joined #tagmem
20:28:46 [noah]
HT: With XInclude we can get rid of much of the need for DTDs.
20:30:12 [noah]
DC: The getting rid of DTDs part appeals to me. Tim, do you feel that justifies making XInclude the default.
20:30:48 [masinter]
shouldn't
make normative reference to this?
20:31:05 [noah]
q+ to ask whether this is clear on what to do if external resources don't resolve. Can you use this in a non-network environment?
20:31:10 [DanC_]
ack danc
20:31:10 [Zakim]
DanC_, you wanted to express obligation to connect with SemWeb CG
20:31:49 [DanC_]
TBL: what does the xml:id bit do?
20:31:57 [DanC_]
HT: affects the DOM; e.g. GetElementById
20:32:32 [johnk]
q+ to ask what happens if the document looks like this: <xml version='1.0'?><EncryptedData>...</EncryptedData>
20:33:13 [DanC_]
TBL: does xinclude happen after xml:id?
20:33:33 [DanC_]
HT: no; the details are in XProc
20:33:51 [DanC_]
***** HT wants to remember that this could be clarified
20:34:41 [DanC_]
(tee hee... johnk is going to ask the question that's at the heart of the matter, opening up the risk that this agendum will take up the rest of the meeting :)
20:35:30 [DanC_]
TBL: I'm surprised to not see something recursive
20:35:36 [timbl_]
q?
20:35:49 [DanC_]
HT: XInclude is recursive; unlike GRDDL, which doesn't say whether xinclude happens 1st, xinclude does say
20:35:56 [noah]
q?
20:36:04 [masinter]
q?
20:36:45 [DanC_]
ack johnk
20:36:45 [Zakim]
johnk, you wanted to ask what happens if the document looks like this: <xml version='1.0'?><EncryptedData>...</EncryptedData>
20:36:59 [DanC_]
JK: what if the data is encripted?
20:37:24 [DanC_]
HT: well... you lose... we tried to get encryption/signature into the design, but... they require a key...
20:37:54 [noah]
ack next
20:37:55 [Zakim]
masinter, you wanted to ask whether this belongs with the application/xml media type & reregistration of it
20:37:56 [DanC_]
... and we don't want to come anywhere close to encourage packaging a document with a key
20:38:17 [DanC_]
q+
20:38:48 [DanC_]
LMM: how about binding it to the XML media type?
20:39:19 [DanC_]
HT: not retrospectively
20:40:00 [DanC_]
LMM: but how about when people make new XML media types, they should be referred to this processing model
20:40:04 [masinter]
20:40:50 [noah]
NM As I recall, schema looked at this a long time, asking "do you want to validate pre or post inclusion. The answer was a clear "both", that's as a good reason to use the infoset.
20:40:56 [ht]
20:40:57 [noah]
s/NM/NM:/
20:41:01 [DanC_]
TBL: what "the customer", me, asked for, is what "corresponds to" the input, in the HTTP sense
20:41:33 [noah]
ack next
20:41:34 [Zakim]
noah, you wanted to ask whether this is clear on what to do if external resources don't resolve. Can you use this in a non-network environment?
20:41:37 [timbl_]
In the sense, if you send me an XML document, whot I can hold you to haveing said
20:42:33 [ht]
q+ to answer Tim
20:42:35 [DanC_]
NM: meanwhile, HT has an action to lay out the design space
20:42:36 [DanC_]
action-113?
20:42:36 -01-01 -- OPEN
20:42:36 [trackbot]
20:43:01 [masinter]
e.g., the XML Media Types RFC could require, at a minimum, that registration of XML media types MUST clearly identify what processing model they use, and whether they use this one.
20:43:22 [masinter]
q?
20:43:23 [noah]
q?
20:43:27 [noah]
ack next
20:43:27 [DanC_]
(w.r.t. wrapping up, I'm content to consider action-239 done and come back when we see progress on action-113, provided it comes before LC on this spec)
20:43:29 [timbl_]
q+ to explain as patiently as he can that the interesting thing i snot to tell people how they shoul dprocess it. in fact the idea of a processing model is (of course) (at all) broken. But ut i s the current phrseology for the closest thing to what we need. What we need is some sense of what the meaning of the document is.
20:43:57 [noah]
ack next
20:43:58 [Zakim]
ht, you wanted to answer Tim
20:44:02 [timbl_]
The meaning of an xinclude include emeplemnt is t its included contents.
20:44:47 [DanC_]
HT: yes, it's a reasonable exercise to answer "what is the author held to?"
20:45:04 [DanC_]
... and the value increases if there's only one answer
20:45:22 [DanC_]
... that's why there's no answer in the case you gave [oops; what case was that? I didn't scribe it]
20:45:45 [DanC_]
... this only takes one step down a complicated [... more]
20:45:52 [noah]
q?
20:46:01 [noah]
q+ to ask how widely deployed XInclude is
20:46:02 [masinter]
q+ to suggest TAG ask authors of XML Media Types to reference this document, and require, at a minimum, that registration of XML media types MUST clearly identify what processing model, and whether it uses this one.
20:46:11 [jar]
q+ jar to ask whether any infoset will contain an xinclude element. and ask about OWL imports
20:46:12 [noah]
ack next
20:46:13 [Zakim]
timbl_, you wanted to explain as patiently as he can that the interesting thing i snot to tell people how they shoul dprocess it. in fact the idea of a processing model is (of
20:46:18 [Zakim]
... course) (at all) broken. But ut i s the current phrseology for the closest thing to what we need. What we need is some sense of what the meaning of the document is.
20:46:58 [DanC_]
(I encourage jar, lmm to q- and wait for telcon time, unless there's nothing else on today's agenda that you care about)
20:47:03 [DanC_]
(and noah
20:47:05 [DanC_]
)
20:47:23 [DanC_]
TBL: [...missed] which is the decrypted material...
20:47:32 [DanC_]
... and in the case of XSLT is the output
20:47:47 [DanC_]
... so in fact you have to go to the spec for each element to get what the author is held to
20:48:14 [jar]
TBL was talking about the recursive / compositional processing model.
20:48:57 [noah]
q?
20:48:57 [jar]
I think he's saying this spec isn't ambitious (inferential?) enough
20:49:13 [jar]
q- jar
20:50:02 [DanC_]
HT: LMM, yes, I take on board the concern about the connection between the XML media types spec and this spec
20:50:26 [masinter]
q- masinter
20:50:28 [DanC_]
... though I'm concerned about the timelines
20:51:15 [DanC_]
close ACTION-292
20:51:16 [trackbot]
ACTION-292 Alert group to review HTML Authoring Drafts [trivial] [self-assigned] closed
20:51:32 [DanC_]
Topic: HTML versioning change proposal
20:52:13 [DanC_]
Zakim, remind us in 15 minutes that we said we'd move to the next agendum in 20 minutes
20:52:13 [Zakim]
ok, DanC_
20:52:21 [masinter]
20:53:45 [DanC_]
LMM: you can see the suggested syntax at the bottom
20:53:53 [DanC_]
DC: hmm... DOCTYPE... despite my advice?
20:54:02 [DanC_]
LMM: I looked and couldn't find any downside
20:54:06 [DanC_]
DC: quirks mode?
20:54:56 [DanC_]
LMM: no, quirks mode is triggered only in the case of known DTD strings
20:55:35 [DanC_]
LMM: a goal is to make a change that needs no changes from browsers
20:55:50 [DanC_]
NM: what's the motivation/goal for the change?
20:56:14 [DanC_]
LMM: cf the change proposal, incl "The html version string is allowed primarily because it may be useful for content management systems and other development workflows as a kind of metadata to indicate which specification was being consulted when the HTML content was being prepared.
20:56:14 [DanC_]
"
20:57:50 [DanC_]
HT notes another procedural request from maciej
20:58:59 [DanC_]
HT: this looks good to me.
20:59:20 [DanC_]
HT: yes, we should look into the XML requirement for a system identifier
20:59:29 [DanC_]
s/we should/I hope to/
21:00:42 [DanC_]
HT: ah... yes... there are no XML syntaxes with only public id
21:02:26 [DanC_]
(train of thought started with something NM said, which I forgot)
21:02:39 [DanC_]
DC: that's why I advise a version attribute
21:03:01 [DanC_]
LMM: I wanted to follow the existing tradition of using <!DOCTYPE >
21:03:31 [DanC_]
DC: but it suggests there's a DTD, while there isn't one
21:03:52 [DanC_]
HT: well, a DTD with all "ANY" content models could be slotted in.
21:04:36 [DanC_]
LMM: in some ways I don't have a strong opinion on this issue, but ...
21:05:04 [DanC_]
... I don't like to see the HTML WG close issues just because noone was willing to take flack for making a proposal
21:05:41 [ht]
Actually, forget ANY -- if it goes that way, I would expect/recommend that an effectively empty external subset should be provided at the given SYSID, i.e one consisting entirely of a comment
21:06:03 [DanC_]
... and I think it's important for those who want to express a version id to be able to
21:06:22 [DanC_]
... I encourage TAG members to review and contribute directly to public-html
21:06:40 [DanC_]
some discussion of public-html mailing list logistics and expectations
21:07:14 [Zakim]
DanC_, you asked to be reminded at this time that we said we'd move to the next agendum in 20 minutes
21:07:40 [DanC_]
Topic: HTML media type and pre-HTML 5 content
21:08:09 [DanC_]
action-334?
21:08:09 [trackbot]
ACTION-334 -- Henry S. Thompson to start an email thread regarding the treatment of pre-HTML5 versions in the media type registration text of HTML5 -- due 2009-11-26 -- PENDINGREVIEW
21:08:09 [trackbot]
21:08:32 [DanC_]
RESOLVED: to thank Amy for hosting arrangements. with applause
21:09:11 [DanC_]
21:09:21 [johnk]
Jonathan how about:
21:09:27 [DanC_]
HT: so that collects all relevant materials I know of
21:11:32 [jar]
johnk, that's amazing, thanks
21:15:47 [DanC_]
what's "suspended animation"? wild... they use tracker:closed
21:17:16 [DanC_]
->
ISSUE-53 mediatypereg Need to update media type registrations
21:18:10 [DanC_]
"State:
21:18:10 [DanC_]
CLOSED
21:18:10 [DanC_]
Product:
21:18:10 [DanC_]
HTML5 Spec - PR Blockers"
21:19:22 [DanC_]
q+
21:20:20 [DanC_]
HT: so... should we try to get something to happen before Last Call? I thought there was an interaction with the language design, but on close examination, I didn't find one.
21:21:01 [masinter]
q+ to ask for volunteer to write a change proposal
21:21:35 [masinter]
this is a useful as a Rationale for the change proposal
21:21:43 [noah]
ac2 n6ah
21:21:45 [noah]
ack noah
21:21:45 [Zakim]
noah, you wanted to ask how widely deployed XInclude is
21:21:48 [noah]
ack next
21:22:15 [noah]
DC: I don't agree with the obvious fix. I think the HTML 5 spec describes HTML 2 better than HTML 2 spec does.
21:22:41 [noah]
q?
21:23:23 [DanC_]
ack danc
21:23:23 [noah]
ack next
21:23:26 [Zakim]
masinter, you wanted to ask for volunteer to write a change proposal
21:23:52 [ht]
q+ to point out that each step has ruled out tags, so those tags have _no_ semantics to an HTML5 processor
21:24:32 [DanC_]
LMM: I think a change proposal would be good... e.g. there are documents that prompt quirks mode that's implemented, but the current HTML 5 spec rules it out. [roughly]
21:30:26 [masinter]
suggest MIME registration point to history section inside HTML5 document and/or previous MIME registration
21:30:26 [masinter]
21:30:44 [DanC_]
. ACTION DanC: ask HTML WG team contacts to make a change proposal re issue-53 mediatypereg informed by HT's analysis and today's discussion
21:31:09 [DanC_]
ACTION DanC: ask HTML WG team contacts to make a change proposal re issue-53 mediatypereg informed by HT's analysis and today's discussion
21:31:10 [trackbot]
Created ACTION-364 - Ask HTML WG team contacts to make a change proposal re issue-53 mediatypereg informed by HT's analysis and today's discussion [on Dan Connolly - due 2009-12-17].
21:31:23 [ht]
It occurs to me that a change which said "this registration augments [the existing registration] rather than replacing it
21:31:56 [DanC_]
LMM: a change proposal might fix some other parts of the media type registration... e.g. change controller
21:32:20 [noah]
topic: Widget URI Scheme
21:32:28 [masinter]
21:33:42 [DanC_]
Zakim, remind us in 12 minutes to check the clock
21:33:42 [Zakim]
ok, DanC_
21:34:45 [DanC_]
LMM: there's a TAG issue about registering URI schemes [really?]; I think we should encourage registering permanent URI schemes rather than provisional ones... but leaving that aside...
21:35:08 [johnk]
21:36:02 [DanC_]
rather
21:36:22 [timbl_]
21:36:25 [DanC_]
LMM: consider "A producer may include an authority component in URIs. If present, the authority component is said to be opaque, meaning that the authority component has a syntax as defined by [RFC3987] but that the authority component is devoid of semantics. "
21:36:37 [DanC_]
LMM: this seems not well-defined
21:37:36 [DanC_]
LMM: earlier in the design discussion, this was used for cross-widget references , but due to security concerns, I think, they made it opaque
21:38:08 [DanC_]
JAR: how about using it to distinguish widgets?
21:39:20 [DanC_]
JK: but these are only used for reference within a widget
21:41:21 [johnk]
JK: widget URIs are used in a "manifest" contained within a widget package, and then used to point to other files within the widget package
21:41:26 [masinter]
21:41:40 [masinter]
guidelines and registration procedures for new uri schemes
21:42:31 [johnk]
q+ to ask whether the crucial question is whether individual components of a widget will be "on the Web"
21:43:00 [DanC_]
TBL: this does seem undefined
21:43:07 [DanC_]
JAR: could be "reserved for future use"
21:43:10 [masinter]
For schemes that function as locators, it is important that the
21:43:10 [masinter]
mechanism of resource location be clearly defined. This might mean
21:43:10 [masinter]
different things depending on the nature of the URI scheme.
21:43:10 [masinter]
21:43:13 [masinter]
21:43:55 [masinter]
The URI registration process is described in the terminology of [3].
21:43:55 [masinter]
The registration process is an optional mailing list review, followed
21:43:55 [masinter]
by "Expert Review". The registration request should note the desired
21:43:55 [masinter]
status. The Designated Expert will evaluate the request against the
21:43:58 [masinter]
criteria of the requested status. In the case of a permanent
21:44:00 [masinter]
registration request, the Designated Expert may:
21:44:04 [masinter]
21:44:11 [masinter]
I am not the expert.
21:45:42 [Zakim]
DanC_, you asked to be reminded at this time to check the clock
21:47:10 ]."
21:47:10 [masinter]
21:48:34 [DanC_]
Topic: Closing remarks
21:49:14 [DanC_]
AM: This was a very successful ftf.
21:50:29 [DanC_]
JK: yeah; good meeting; the action item stuff in the agenda worked; the Zakim tracking not so well.
21:50:33 [DanC_]
NM: yeah.
21:51:15 [DanC_]
TBL: yeah... good meeting... JAR's "speaks_for" stuff was a highlight
21:51:25 [DanC_]
q+ to speak to the persistent domain tactics
21:51:32 [DanC_]
q- ht
21:52:12 [DanC_]
TBL: the persistent domain stuff... not clearly within the TAG's scope, but if not us, who?
21:52:40 [DanC_]
JAR: yeah... Creative Commons will sure help... but who else is in a position to connect the IETF with the library community?
21:53:01 [johnk]
ack johnk
21:53:01 [Zakim]
johnk, you wanted to ask whether the crucial question is whether individual components of a widget will be "on the Web"
21:53:05 [jar]
who else other than the TAG, that is
21:53:16 [jar]
and CC
21:53:18 [DanC_]
NM: yeah... good meeting... noteable technical highlights
21:53:30 [jar]
(not a rhetorical question by the way)
21:53:42 [DanC_]
... and as to how we work as a group, this feels like we're starting to hit stride.
21:53:51
21:53:51 [masinter]
done" state.
21:54:24 [DanC_]
ack me
21:54:24 [Zakim]
DanC_, you wanted to speak to the persistent domain tactics
21:55:00 .
21:55:58 [DanC_]
DC: yeah... not clear that persistent domains is a TAG thing, but it's a W3C thing, and if we can catalyze a workshop, that makes sense
21:56:43 [DanC_]
... and several of the topics that came up in the meeting kept me thinking into the evening
21:57:54 [DanC_]
next meeting looks like 17 Dec
21:58:55 [DanC_]
JAR: [scribe too sleepy...] I'm starting to feel more in sync with the group
21:59:18 [DanC_]
ADJOURN
21:59:54 [DanC_]
action-213?
21:59:54 [trackbot]
ACTION-213 -- Noah Mendelsohn to prepare 17 Dec weekly teleconference agenda -- due 2009-12-16 -- PENDINGREVIEW
21:59:54 [trackbot]
22:08:23 [DanC_]
close action-330
22:08:23 [trackbot]
ACTION-330 Prepare Dec f2f agenda in collaboration with Noah etc. closed
22:09:54 [DanC_]
action-239
22:09:58 [DanC_]
close action-239
22:09:58 [trackbot]
ACTION-239 alert chair when updates to description of xmlFunctions-34 are ready for review (or if none made) closed
22:10:20 [DanC_]
close action-277
22:10:20 [trackbot]
ACTION-277 Ensure patent policy issue is resolved with Art closed
22:12:27 [DanC_]
close action-306
22:12:27 [trackbot]
ACTION-306 Work with Raman, LM, JK to update Web APplication architecture outline based on discussions at TAG meetings closed
22:12:34 [DanC_]
action-327
22:13:14 [DanC_]
close action-328
22:13:14 [trackbot]
ACTION-328 Convey to the EXIWG the resolution "We thank the EXI WG for registering the conetnt encoding and encourage them in their endeavours.". closed
22:13:58 [DanC_]
close action-334
22:13:58 [trackbot]
ACTION-334 Start an email thread regarding the treatment of pre-HTML5 versions in the media type registration text of HTML5 closed
22:15:48 [Zakim]
-[MIT-G449]
22:15:50 [Zakim]
TAG_f2f()8:30AM has ended
22:15:50 [Zakim]
Attendees were [MIT-G449], Raman
22:17:08 [jar]
jar has joined #tagmem
22:31:09 [raman]
raman has left #tagmem
22:31:36 [jar]
jar has joined #tagmem
23:19:26 [timbl]
timbl has joined #tagmem
23:20:05 [timbl]
timbl has joined #tagmem | http://www.w3.org/2009/12/10-tagmem-irc | CC-MAIN-2015-11 | refinedweb | 13,126 | 65.46 |
For a deeper look into our Eikon Data API, look into:
Overview | Quickstart | Documentation | Downloads | Tutorials | Articles
I want to use python to automate an excel+eikon workflow. I tried to rebuild all of my excel API calls with eikon's python package, but not all required data was supported.
My excel file is .xlsm, and it needs to connect to eikon then update before I manipulate data in python. I'm using win32com as follows:
import win32com.client as win32 excel = win32.gencache.EnsureDispatch('Excel.Application') wb = excel.Workbooks.Open(os.getcwd() + '\\MyFile.xlsm') ws = wb.Worksheets('Sheet_With_Eikon_API_Calls')
This code opens excel, then opens my worksheet with excel eikon api calls. However, this doesn't launch the Thomson Reuters Eikon COM Add-in, so my data doesn't get updated. For my process to work, I need to launch the Eikon Add-in then update the data. Is this possible with win32com? The steps I want are:
python code: 1. launch excel 2. go to excel worksheet that has eikon api calls 3. launch excel thomson reuters eikon comm add-in (or verify that it's on) 4. refresh excel eikon api calls 5. save fresh data as .csv, then manipulate data with pandas and auto generate reports
Try adding
excel.COMAddIns("PowerlinkCOMAddIn.COMAddIn").Connect = True
I have the same problem, i tried with
xl = win32com.client.gencache.EnsureDispatch('Excel.Application')
xl.COMAddIns("PowerlinkCOMAddIn.COMAddIn").Connect = True
but it doesnt work
When posting a new question on these forums always start a new thread. Old threads with accepted answers are not monitored by moderators. If you need to reference an old thread in your question, include a link to the old thread.
To determine what's happening make the Excel instance you're creating visible (add xl.Visible = True right after creating an instance of Excel application). In the instance of Excel created do you see Refinitiv or Thomson Reuters tab added to Excel ribbon?
Issue while requesting Stock Returns (TR.TotalReturn1D)
How can I import a shareholder history report through the eikon python API?
Refinitiv add-in excel (Mac) creates formula but does not give any result
For 2 stocks listed on same exchange I get different number of rows of historical data and missing minutes
Downloading excel file from eikon link with python | https://community.developers.refinitiv.com/questions/29464/launch-excel-com-add-in-with-python-win32com.html?sort=oldest | CC-MAIN-2022-27 | refinedweb | 386 | 59.3 |
Current JT only process (clone) BBs with multiple successors in JT with the aim to thread the predecessor with a successor BB. This misses opportunities to to handle return BB where the return value can be simplified with threading (cloning).
Example:
#include <array>
#include <algorithm>
constexpr std::array<int, 3> x = {1, 7, 17};
bool Contains(int i) {
return std::find(x.begin(), x.end(), i) != x.end();
}
Clang produces inefficient code:
_Z8Containsi: # @_Z8Containsi
.cfi_startproc
.LBB0_1:
movl $_ZL1x, %eax
jmp .LBB0_5
.LBB0_3:
cmpl $17, %edi
movl $_ZL1x+8, %ecx
movl $_ZL1x+12, %eax
cmoveq %rcx, %rax
.LBB0_5:
movl $_ZL1x+12, %ecx
cmpq %rcx, %rax
setne %al
retq
While GCC produces:
_Z8Containsi:
.LFB1534:
.cfi_startproc
movl $1, %eax
cmpl $1, %edi
je .L1
cmpl $7, %edi
je .L1
cmpl $17, %edi
sete %al
.L1:
ret
This patch address the issue. After the fix, the generated code looks like:
.cfi_startproc
addl $-1, %edi
cmpl $16, %edi
ja .LBB0_2
movl $65601, %eax # imm = 0x10041
movl %edi, %ecx
shrl %cl, %eax
andb $1, %al
retq
.LBB0_2: # %_ZSt4findIPKiiET_S2_S2_RKT0_.exit.thread
xorl %eax, %eax
retq
If the terminator is a "ret", or some arbitrary terminator that doesn't simplify, it's not really "threading"; it's just tail duplication. That's likely profitable in some cases, but using ThreadEdge to perform the transform seems confusing.
JumpThreading is basically basic block cloning followed by control flow simplification. This is just a special case where the second part is missing.
There is already another special case in JT -- if all the Pred's target successor is the same, there is no threading either -- basically there is only control flow simplification part without the basic cloning. These two cases are just at two different ends of the spectrum.
I change the testcase a little so the terminator won't be ret, but the generated code pattern is the same. Should it be handled as well?
------------------------------------
#include <array>
#include <algorithm>
constexpr std::array<int, 3> x = {1, 7, 17};
bool global, cond;
void Contains(int i) {
global = std::find(x.begin(), x.end(), i) != x.end();
if (cond)
__builtin_printf("hello\n");
}
------------------------------------
Handling what Wei's case will be a nice thing to have, but it may require more significant change in JT. Currently the JT candidate BB selection is based on checking the conditional value used by branch or return value of ret instr (with this patch).
To handle this case, it requires checking use values of arbitrary instructions (value of store in the example). Another thing to consider is the cost model difference. In Wei's case, cloning really becomes tail dup with increased complexity of control flow (handling Ret instruction on the other hand does not have the issue).
Handling what Wei's case will be a nice thing to have, but it may require more significant change in JT.
I think we need to have a plan for what this is going to look like, so the new code here doesn't immediately become obsolete.
Another thing to consider is the cost model difference.
I think the necessary cost model is effectively the same for ret vs. other instructions. In particular, the "ret" might go away after after inlining.
I'm surprised threadEdge still works. Probably want to update the documentation for that API if we really want to allow SuccBB to be null.
Ping.
Nit: if (!RV || !(Condition = dyn_cast<CmpInst>(RV))) return false;
For BB being handled in this patch (containing Ret instruction), OnlyDest is always nullptr so this block will not be executed for it. Is it for other purpose?
For BB with Ret instruction, we don't factor predecessors with the same PredVal here. If we factor predecessors with the same PredVal, we may have less clones?
It will be helpful to add some comment for the case that SuccBB is nullptr and maybe a TODO for the extension and refactoring needed.
Tests need to be processed with opt -instnamer.
ok
This simplifies the ret instruction after the condition is removed.
Right. This can be a TODO.
Ok.
ok. Will document as a follow up.
rebased and addressed review feedbacks. | https://reviews.llvm.org/D68898 | CC-MAIN-2020-50 | refinedweb | 685 | 65.32 |
On Thu, 2008-11-13 at 11:19 -0600, Chris Mellon wrote: > On Thu, Nov 13, 2008 at 11:16 AM, Joe Strout <joe at strout.net> wrote: > > One thing I miss as I move from REALbasic to Python is the ability to have > > static storage within a method -- i.e. storage that is persistent between > > calls, but not visible outside the method. I frequently use this for such > > things as caching, or for keeping track of how many objects a factory > > function has created, and so on. > > > > Today it occurred to me to use a mutable object as the default value of a > > parameter. A simple example: > > > > def spam(_count=[0]): > > _count[0] += 1 > > return "spam " * _count[0] > > > >>>> spam() > > 'spam ' > >>>> spam() > > 'spam spam ' > > > > This appears to work fine, but it feels a little unclean, having stuff in > > the method signature that is only meant for internal use. Naming the > > parameter with an underscore "_count" makes me feel a little better about > > it. But then, adding something to the module namespace just for use by one > > function seems unclean too. > > > > What are your opinions on this idiom? Is there another solution people > > generally prefer? > > > > Ooh, for a change I had another thought BEFORE hitting Send rather than > > after. Here's another trick: > > > > def spam2(): > > if not hasattr(spam2,'count'):spam2.count=0 > > spam2.count += 1 > > return "spam2 " * spam2.count > > > > This doesn't expose any uncleanliness outside the function at all. The > > drawback is that the name of the function has to appear several times within > > itself, so if I rename the function, I have to remember to change those > > references too. But then, if I renamed a function, I'd have to change all > > the callers anyway. So maybe this is better. What do y'all think? > > > > Static storage is a way of preserving state. Objects are a way of > encapsulating state and behavior. Use an object. He is using an object. Specifically, he's using a function object. Though perhaps you meant put it into a class. Here are a few essays into the matter >>> def foo(): ... foo._count += 1 ... return ("spam " * foo.count).rstrip() ... >>> foo._count=0 >>> foo() 'spam' >>> foo() 'spam spam' >>> Simple and straightforward, and _count is still encapsulated in the function, but it's kind of ugly, because when the function has been defined, it is not functional. Attempt #2 -- put it in a decorator >>> def add_counter(f): ... f._count = 0 ... return f ... >>> @add_counter ... def foo(): ... foo._count += 1 ... return ("spam " * foo._count).rstrip() >>> foo() 'spam' >>> foo() 'spam spam' >>> Now it's complete as soon as the function is defined, but the decorator is tightly bound to the function, in its use of _count. I find that kind of ugly. This is the first decorator I've written that doesn't define a function inside itself. Try three. Let's put it in a class: >>> class Foo(object): ... def __init__(self, counter_start=0): ... self._count = counter_start ... def __call__(self): ... self._count += 1 ... return ("spam " * self._count).rstrip() ... >>> foo = Foo() >>> foo() 'spam' >>> foo() 'spam spam' >>> Essentially, this has the same behavior as the other two. But it looks cleaner, and you don't have to worry about coupling separate functions, or refering to a function by name within itself (because you have self to work with). But the "object" semantics are essentially the same, and state is just as legitimately preserved on a function object as a Foo object. Cheers, Cliff | https://mail.python.org/pipermail/python-list/2008-November/511456.html | CC-MAIN-2014-10 | refinedweb | 574 | 65.83 |
You probably might have heard about Async/Await keywords in other languages such as JavaScript or Dart, and how we use them for asynchronous programming. In this article we'll see how to utilize them and write asynchronous program.
What is Asynchronous Programming?
Computer programs are typically synchronously on a single thread, this implies that that one task must complete before another task runs. This can be fine in small programs that doesn't do any form of I/O.
Asynchronous programming has to do with writing programs that executes multiple tasks concurrently in order not to leave the CPU idle.
Why write Asynchronous code?
Let's assume that we write a program that fetches data from a web service, the program fetches a list of users and a list of latest posts.
def fetch_posts(): result = request('url') display(result) def fetch_users(): result = request('url') display(result) def main(): fetch_posts() fetch_users() main()
In the pseudo-code above, the code runs synchronously. Network requests usually take time to get a response, while the program is waiting a response the CPU lies idle. Let's assume a network request takes 2 secs to resolve it means that the above program will take a little above four seconds to resolve. But if we write the program asynchronously we can run the two tasks(
fetch_posts() and
fetch_users()) concurrently.
Lets see an example that emulates a synchronous approach and another example that take an asynchronous approach.
Synchronous approach
If you run the above program it takes a little over three seconds to complete, that is because the
fetch_users() function waits for the
fetch_posts() function to complete before it starts running.
Let's look at an asynchronous way of writing the same program.
The program above runs in approximately 2 secs as opposed to the 3 secs which the synchronous approach takes. In this case the difference seems small but when working on real world applications, the difference can be huge.
So, we all know how to write synchronous programs, lets see the APIs that enable us write asynchronous code in python.
Writing Asynchronous code in python
Event Loop
In order for us to write asynchronous code, we need an event loop.
An event loop is a programming construct that waits for and dispatches events or messages in a program. The event loop is basically what executes each task in a single threaded application. The event loop can be found in the
asyncio package.
Coroutines
You also need a coroutine. What is a coroutine? A coroutine in python a function or method that can pause it's execution and resume at a later point. Any task that needs to be run asynchronously needs to be a coroutine. You define a coroutine with
async def. Coroutines are awaitable and can not be executed by simply calling the function. Prior to Python 3.5 the
async keyword was not available in python, coroutines were created as a generator functions decorated with
@asyncio.coroutine. You can read more about them here.
Let's see how they all work together.
One on the rules of writing asynchronous code is that coroutines can not contain blocking code.
time.sleep(secs) is a blocking code. Using
time.sleep(secs) in our asynchronous example will make it run synchronously.
asyncio.sleep(secs) is not a blocking code.
asyncio.sleep(secs) represents an asynchronous task that can be awaited. Trying to await a non-awaitable task results to en exception.
One common mistake people new to writing asynchronous in python make is forgetting to await coroutines and other awaitables.
As someone who has written a fair amount of JavaScript, I expected functions marked with
async to behave exactly as the one in JavaScript.
Some differences between JavaScript and Python Async Functions.
JavaScript async functions run on a seperate thread and returns to the main
thread on completion but Python async functions run a single thread and only
switch to another coroutine when an asynchronous I/O operation is encountered.
Consider this program.
In this program I made the event loop switch to another coroutine after every 1000 count. When you run the program, you'll notice that the second coroutine finishes before the first. All coroutine should be awaiting something in order for your code to be asynchronous. Remember everything runs on a single thread, so it's your responsibility to manage it. You can play with the repl to get used to
async/await and
asyncio.
Here is the same program written using different
asyncio API.
From the code above you can see that i didn't call
asyncio.get_event_loop(), this is because
asyncio.run() is equivalent to
loop = asyncio.get_event_loop() and
loop.run_until_complete.
One of the benefits of using
asyncio.gather() over
asyncio.wait() is the ease of getting return values of the coroutines.
asyncio.gather() when awaited returns a list containing all return values.
Check out this Stackoverflow question If you want to know how to get back your return value from your coroutines.
asyncio APIs.
asyncio documentation.
Thanks for reading and I hope you enjoyed the article.
Discussion
Awesome post bro. Though you mixed gists and native code highlight. | https://practicaldev-herokuapp-com.global.ssl.fastly.net/code_enzyme/introduction-to-using-async-await-in-python-2i0n | CC-MAIN-2021-04 | refinedweb | 859 | 66.23 |
[NT] SpeakFreely Malformed GIF Vulnerability
From: SecuriTeam (support_at_securiteam.com)
Date: 09/23/03
- Previous message: SecuriTeam: "[EXPL] hztty Buffer Overflow Exploit Code (-I)"
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] [ attachment ]
To: list@securiteam.com Date: 23 Sep 2003 15:59:49 +0200
The following security advisory is sent to the securiteam mailing list, and can be found at the SecuriTeam web site:
- - promotion
The SecuriTeam alerts list - Free, Accurate, Independent.
Get your security news from a reliable source.
- - - - - - - - -
SpeakFreely Malformed GIF Vulnerability
------------------------------------------------------------------------
SUMMARY
<> SpeakFreely is "a very interesting
real-time voice application with cryptographic support developed by John
Walker and now the project will be continued on Sourceforge by a group of
programmers and fans. The program is multiplatform, opensource and is also
used as add-on of ICQ".
A vulnerability in the way SpeakFreely handles GIFs allows remote
attackers to cause the program to crash.
DETAILS
Vulnerable systems:
* SpeakFreely version 7.6a
SpeakFreely for Windows has a nice feature called "Show your face" that
lets users to send an image (bmp and gif) to the others and it is enabled
by default.
Unfortunally in the program there is a "forgotten check", so if the
function GlobalAlloc() fails there are no instruction to check its return
value.
The problem happens with GIF files that have a content (only the values
"Image width" and "Image height" in the header, not the real content) too
big or equal to zero and so they are unallocable in memory. The crash will
happen when the program will try to use the pointer returned by the
unchecked function.
The following are 2 examples:
A] 0000.gif
0000000: 4749 4638 3961 0000 0000 0000 002c 0000 GIF89a.......,..
0000010: 0000 0000 0000 00 .......
| |
Crash:
:00416227 8A0439 mov al, byte ptr [ecx+edi] (ecx+edi is an unreacheable
location)
B] ffff.gif
0000000: 4749 4638 3961 0000 0000 0000 002c 0000 GIF89a.......,..
0000010: 0000 ffff ffff 00 .......
| |
Crash:
00415CF8 668910 mov word ptr [eax], dx (eax is 0)
Recreation:
A] You must create a custom GIF file manually (with a hex editor) or you
can also use my small tool ("gifbug file.gif" or "gifbug -iw 0 -ih 0
file.gif"): <> (attached at the end)
B] Then you must select the malformed GIF from your SpeakFreely client
(Options -> Show your face -> Browse)
C] You must connect to the victim (Connection -> New)
D] And then you need to talk or just to press the left mouse button on the
dialog box appeared
E] The victim should be crashed
(NOTE: you can also wait an incoming connection and passively crashing the
client)
Workaround:
Disable the option "Show faces of other users" from the menu Options ->
Show your face.
Tool (Custom GIF Creator):
/*
by Auriemma Luigi
This simple utility creates a tiny GIF files that "seems" a huge GIF
image 8-)
Some notes about the program are that it use maximum color depth,
maximum logical screen size and the user can specify how big must
be the image in memory.
Effects of the malformed GIF can be freeze of the application with
CPU at 100%, memory consumption through the allocation of the bytes
specified by the user (generally weidth * heigth * color_depth),
crash of the application with the possibility to execute code and
many other effects that are specifics for each program that reads
GIF files (naturally if an application makes the right checks on
the malformed GIF it will not be vulnerable)
LINUX & WIN32 VERSION
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define VER "0.1"
#define WHMAX 0xffff
#define CRMAX 0x7
#pragma pack(1)
struct header {
unsigned char signature[3];
unsigned char version[3];
};
struct logical_screen {
unsigned short width;
unsigned short height;
unsigned char gctf:1;
unsigned char color_res:3;
unsigned char sort:1;
unsigned char sgct:3;
unsigned char back_color_index;
unsigned char pixel_ratio;
};
struct image {
unsigned char separator;
unsigned short left_pos;
unsigned short top_pos;
unsigned short width;
unsigned short height;
unsigned char lctf:1;
unsigned char interlace:1;
unsigned char sort:1;
unsigned char reserved:2;
unsigned char slct:3;
};
struct gif_head {
struct header header;
struct logical_screen logical_screen;
struct image image;
} gif_head;
void std_err(void);
int main(int argc, char *argv[]) {
FILE *fd;
unsigned short sw = WHMAX,
sh = WHMAX,
cr = CRMAX,
iw = WHMAX,
ih = WHMAX,
i;
setbuf(stdout, NULL);
fputs("\n"
"Custom GIF creator "VER"\n"
"by Luigi Auriemma\n"
"web:\n"
"\n", stdout);
if(argc < 2) {
printf("\n"
"Usage: %s [options] <GIF_output>\n"
"\nOptions:\n"
"-sw NUM Screen width size (default, MAX: %d)\n"
"-sh NUM Screen height size (default, MAX: %d)\n"
"-cr NUM Color resolution (default, MAX: %d)\n"
"-iw NUM Image width size (default, MAX: %d)\n"
"-ih NUM Image height size (default, MAX: %d)\n"
"\n"
"NOTE: if the application to test says that cannot allocate memory\n"
" for the image, simply set a minor Image width and heigth\n"
"\n", argv[0],
WHMAX, WHMAX,
CRMAX,
WHMAX, WHMAX);
exit(1);
}
argc--;
for(i = 1; i < argc; i++) {
if(!memcmp(argv[i], "-sw", 3)) { sw = atoi(argv[++i]); continue; }
if(!memcmp(argv[i], "-sh", 3)) { sh = atoi(argv[++i]); continue; }
if(!memcmp(argv[i], "-cr", 3)) { cr = atoi(argv[++i]); continue; }
if(!memcmp(argv[i], "-iw", 3)) { iw = atoi(argv[++i]); continue; }
if(!memcmp(argv[i], "-ih", 3)) { ih = atoi(argv[++i]); continue; }
printf("\nError: Wrong argument (%s)\n", argv[i]);
exit(1);
}
fd = fopen(argv[argc], "wb");
if(!fd) std_err();
/* FILL THE STRUCTURE */
memcpy(gif_head.header.signature, "GIF", 3);
memcpy(gif_head.header.version, "89a", 3);
// memcpy(gif_head.header.version, "87a", 3); /* 89a or 87a are the same
*/
gif_head.logical_screen.width = sw; /* maximum */
gif_head.logical_screen.height = sh; /* maximum */
gif_head.logical_screen.gctf = 0;
gif_head.logical_screen.color_res = cr; /* 3 bits */
gif_head.logical_screen.sort = 0;
gif_head.logical_screen.sgct = 0;
gif_head.logical_screen.back_color_index = 0;
gif_head.logical_screen.pixel_ratio = 0;
gif_head.image.separator = 0x2c; /* descriptor */
gif_head.image.left_pos = 0;
gif_head.image.top_pos = 0;
gif_head.image.width = iw; /* bug */
gif_head.image.height = ih; /* bug */
gif_head.image.lctf = 0;
gif_head.image.interlace = 0;
gif_head.image.sort = 0;
gif_head.image.reserved = 0;
gif_head.image.slct = 0;
fwrite(&gif_head, sizeof(struct gif_head), 1, fd);
fclose(fd);
printf("\nThe file %s has been created\n\n", argv[argc]);
return(0);
}
void std_err(void) {
perror("\nError");
exit(1);
}
ADDITIONAL INFORMATION
The information has been provided by <mailto:aluigi@altervista] hztty Buffer Overflow Exploit Code (-I)"
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] [ attachment ]
Relevant Pages
- [EXPL] Serv-U FTPD "SITE CHMOD" Command Remote Exploit
... The following security advisory is sent to the securiteam mailing list, and can be
found at the SecuriTeam web site: ... unsigned char szCommand;
... // 28 bytes decode by lion, ... void shell (int sock) ... (Securiteam)
- [UNIX] X-Chat Socks5 Buffer Overflow Vulnerability (Exploit)
... The following security advisory is sent to the securiteam mailing list, and can be
found at the SecuriTeam web site: ... unsigned int packetlen,
addrlen; ... unsigned char buf; ... void getshell; ... (Securiteam)
- [EXPL] Quake 3 Buffer Overflow (Exploit)
... The following security advisory is sent to the securiteam mailing list, and can be
found at the SecuriTeam web site: ... port and exit cleanly with
an unsuspicious error message. ... unsigned char ipx; ... int hooklen; //
for both sendservercommand and directconnect ... (Securiteam)
- [EXPL] Microsoft Word Buffer Overflow (Exploit 2)
... The following security advisory is sent to the securiteam mailing list, and can be
found at the SecuriTeam web site: ... Microsoft Word Buffer Overflow
... invalid memory acess and in some cases arbitrary overwrites. ... (Securiteam)
- [EXPL] Windows RPC Universal Exploit
... The following security advisory is sent to the securiteam mailing list, and can be
found at the SecuriTeam web site: ... unsigned char request1={
... DWORD GETSTRCS ... int attack ... (Securiteam) | http://www.derkeiler.com/Mailing-Lists/Securiteam/2003-09/0081.html | crawl-001 | refinedweb | 1,261 | 56.15 |
A SoundShader is a description of a sound with various properties. More...
#include "SoundShader.hpp"
A SoundShader is a description of a sound with various properties.
These properties can be specified by the user through a sound shader script. The sound system uses a sound shader to load soundfiles and play them with sound shader specific properties.
Determines how a sound file is loaded into memory.
SoundType is used to change properties of all sounds from a specific type in the game code.
e.g. Turn volume of player effects down.
Default constructor used to create an "empty" sound shader with default parameters.
This is useful to create a custom sound shader from game code and adjust its parameters manually.
Constructor to create a sound shader from a scriptfile using the passed TextParser.
This constructor is used by the sound shader manager to load sound shaders from script files. Throws TextParserT::ParseError on failure.
The sound file this shader is associated with.
The inner angle of the cone in which the sound is emited at normal volume.
The volume of this sound (inside its sound cone/at minimal distance). 1.0 meaning 100% volume and 0.0 mute sound.
Determines the way this sound shaders file is loaded into memory.
The maximum distance that the sound will cease to attenuate.
The minimum distance that the sound will cease to continue growing louder at (stays at max. volume).
The name of the sound shader.
The number of times this sound should be looped. -1 for infinite, 1 for one time sounds.
The outer angle of the cone outside which the sound is emited at outside volume.
The sounds volume if listener is outside the sound cone.
Pause in seconds between two loops.
Pitch muliplier for this sound.
Priority for sounds using this shader (higher values mean higher priority).
The factor at which the sound is attenuated when listener is outside min distance.
Determines the group this sound belongs to. | https://api.cafu.de/c++/classSoundShaderT.html | CC-MAIN-2018-51 | refinedweb | 328 | 69.07 |
NAME
clearenv - clear the environment
SYNOPSIS
#include <stdlib.h> int clearenv(void); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): clearenv(): _SVID_SOURCE || _XOPEN_SOURCE
DESCRIPTION
The clearenv() function clears the environment of all name-value pairs and sets the value of the external variable environ to NULL.
RETURN VALUE
The clearenv() function returns zero on success, and a non-zero value on failure.
VERSIONS
Not in libc4, libc5. In glibc since glibc 2.0.
CONFORMING TO
Used ALSO
getenv(3), putenv(3), setenv(3), unsetenv(3), environ(7)
COLOPHON
This page is part of release 3.23 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at. | http://manpages.ubuntu.com/manpages/lucid/man3/clearenv.3.html | CC-MAIN-2014-35 | refinedweb | 117 | 58.28 |
548 new
public types:
SELECT TYPES WHERE IsPublic AND WasAdded
21 new mamespaces:
SELECT NAMESPACES WHERE WasAdded
2 namespaces removed:.
[Advertisement]
Pingback from Cuanto se ha cambiado NHibernate desde 1.2.1 hasta 2.0 GA? at Espacio de Dario Quintana
One of the difficulties in developing features for NHibernate and with performing code cleanups is the desire to keep it somewhat in sync with it's older brother Hibernate. There's a constant and necessary struggle between wanting to improve the core and wanting to keep it as true to Hibernate as possible. While I haven't tried to reduce related complexities I imagine it would cause a rather large deviation from Hibernate. Perhaps we can try and get Hibernate to refactor some and then can use those changes as well.
This information is quite interesting. Thanks for providing it.
-Will (Just barely a nhibernate developer.)
Will, I indeed just got this feedback from some others NHibernate developers.
I hope that your team and the Hibernate team will find a way to improve the overall architecture because with such entangling, it must not be fun everyday to develop it.
Pingback from Firebird News » NHibernate 2.0 GA released
This was really interesting, very useful to see detailed stats on changes in assembly versions.
I have studied the nhibernate source and find it very nicely structured and coded, there are of course many ways it could be improved. Stats like this is a really good starting point :)
Pingback from How much has change NHibernate since 1.2.1 till 2.0 GA ? at Dario Quintana
You've been kicked (a good thing) - Trackback from DotNetKicks.com
As always fantastic. Indeed your SP1 post subconsciously 'gave us permission' to add the NDepend analysis.
It just happened, we didn't even think about it to be honest.
We had done this analysis from the earliest bits of the alpha and like most software we use/construct/care about, these artifacts are expected, not optional for us.
CANNOT WAIT for the new version of NDepend.
Actually I am sure you have thought of this, but any plans for 'Linq to CQL'? That would be utterly awesome....
This is good information. Thank-you for doing this.
It does concern me that a framework traditionally used hand in hand with other frameworks to help reduce dependencies (Google 'NHibernate' and 'Dependency Injection' to see what I mean) has so many cross dependencies itself - not good advertisement in my mind.
I think this shows the problem we all face when writing software - when is it time to cut the cord to the past and do a true 'new' version? By trying to encompass all things, we fall apart at the seams in many cases, so sometimes the best thing to do is limit what we try to do and not fall into the jack of all trades, master of none in the 'code' sense of the saying.
We all know NHibernate is powerful in the hands of the right developer who knows how to utilize it correctly, but perhaps a rewrite and decoupling of the past would result in a better framework.
Just my opinion.
Is that 3738.55 seconds to run unit tests (1 hour, 2 minutes) a typo or am I doing my math wrong? That can't be right.
Seems extremely excessive for what appears to be only about 1200 tests if I did my addition right (427 passed, 755 failed, 14 skipped)
Brian, yes more than one hour, no typo problem, I think that tests tried and tried to create unsuccessfully some DB, but that is my own theory.
Damon, yes there are many (many) things in the pipe but cannot talk about it so far.
Pingback from Dew Drop - August 27, 2008 | Alvin Ashcraft's Morning Dew
Patrick, you need to create a database named nhibernate. IThen rerun the test again. It took
3 mins 50 secs 58 msecs to run all the tests in the trunk(and I assume it will take less for the release) and I had 1407 passed 5 failed 38 ignored. 5 failing tests were dialect issues complaining This fixture applies to Firebird, etc.
WTF???? Why is there a dependency on System.Data.OracleClient?????
Jack, after verification:
the method
NHibernate.Driver.OracleClientDriver.CreateConnection()
creates a
System.Data.OracleClient.OracleConnection..ctor()
and the method
NHibernate.Driver.OracleClientDriver.CreateCommand()
System.Data.OracleClient.OracleCommand..ctor()
hence the dependency on System.Data.OracleClient.
With your 'WTF' you point exactly why a tool such as NDepend is essential: the code base structure is often different than what we think it is.
Pingback from NHibernate 2.0 « Beautiful code
Pingback from Jay R. Wren - lazy dawg evarlast » Blog Archive » Lack of Value of Code Metrics
A part of my job as lead developer of the tool NDepend , is to make sure that the product fits real-world
@Patrick
Analyze dependency from classes included inside .NET FW is not necessary and less when you are talking about dialects because all dialects can be extracted from code-base without any problems.
Compare NH1.2 with NH2.0 is unnecessary if you know the history of NH. NH2.0 was a big work and many classes was completely rewritten.
Dependency from castle: 4 hours to remove it completely.
I don't understand if your effort is oriented to have a better NH or to publicize NDepend using NH. If you have a patch to remove some "dependency" remember that we are happy to analyze your proposals.
NHibernate in Zahlen
On NHibernate Quality
Pingback from NHibernate: A Hard-Work and Success Story « WS-KNOWLEDGE
I recently analyzed NUnit v2.4.8 with NDepend . The first impression is that developers behind NUnit
Pingback from Technical Related Notes » Blog Archive » links for 2008-08-26
As I already did with several popular.NET projects like NUnit , NHibernate , .NET Framework , Silverlight
This is a modest number but I am happy to have reached it, especially taking account that I spend | http://codebetter.com/blogs/patricksmacchia/archive/2008/08/26/nhibernate-2-0-changes-overview.aspx | crawl-002 | refinedweb | 1,000 | 64.41 |
9329/what-is-the-peer-node-start-in-hyperledger
Let me explain with an example. Suppose ...READ MORE
You can find the details you want ...READ MORE
When you register a user, that user ...READ MORE
By default, the docs are at your ...READ MORE
Summary: Both should provide similar reliability of ...READ MORE
This will solve your problem
import org.apache.commons.codec.binary.Hex;
Transaction txn ...READ MORE
I know it is a bit late ...READ MORE
If you are new to blockchain then ...READ MORE
TransientMap:
TransientMap contains data that might be used to ...READ MORE
OR
Already have an account? Sign in. | https://www.edureka.co/community/9329/what-is-the-peer-node-start-in-hyperledger | CC-MAIN-2019-47 | refinedweb | 106 | 71.31 |
TANH(3) BSD Programmer's Manual TANH(3)
tanh, tanhf - hyperbolic tangent function
libm
#include <math.h> double tanh(double x); float tanhf(float x);
The tanh() and tanhf() functions compute the hyperbolic tangent of x. For a discussion of error due to roundoff, see math(3).
Upon successful completion, these functions return the hyperbolic tangent value. The following may also occur: 1. If x is +- 0, x is returned. 2. If x is NaN, a NaN is returned. 3. If x is positive infinity, a value 1 is returned; if x is negative infinity, -1 is returned. 4. If x is subnormal, a range error can occur and x is returned.
acos(3), asin(3), atan(3), atan2(3), cos(3), cosh(3), math(3), sin(3), sinh(3), tan(3)
The described functions conform to ISO/IEC 9899:1999 ("ISO C99"). MirOS BSD #10-current September 18,. | https://www.mirbsd.org/htman/i386/man3/tanh.htm | CC-MAIN-2017-04 | refinedweb | 149 | 59.6 |
The weekend IoT warrior is back again!
I bought a pack of 5 BME280s from ebay, unfortunately they sent BMP280s instead and wouldn’t offer a refund. A colleague at work had the same issue, it’s actually really hard to get the BME and not get fobbed off with the BMP. Another colleague mentioned to buy them from this seller on Aliexpress as they’re legit (he had a pack of them in his hand, the right ones!). Anyway, I haven’t ordered them yet so I’ll play with the BMP280 for now, same interface, just lacks the humidity sensor.
Finding the I2C pins
Every board has the potential to use different SDA/SCL pins, fortunately for me, it was printed on the reverse of the board, but you might have to hunt around in the specification sheet of your board to find them.
Finding the I2C device
You can have many devices on the I2C bus, think of it like a public highway with many cars (devices) travelling on it at any time. Each device will have it’s own ID which you’ll need to know to communicate with it in your application. If the manufacturer doesn’t specify the device ID, fortunately there is an easy way to find it using the I2C scanner that Arduino provide, run this sketch and you should see something like the following
Note that I had to override the I2C pins on the Wire.begin(), you might need to do that too.
Scanning... I2C device found at address 0x76 ! done
Writing some code to read data from the sensor
Now I know the I2C pins, and the device address, I can start to write some code. I started off by looking at the example from Mongoose OS, but it seems theres an issue with the Arduino compat library, fortunately theres an answer on the forums.
Here’s where I ended up
#include <mgos.h> #include <Adafruit_BME280.h> #define SENSOR_ADDR 0x76 static Adafruit_BME280 *s_bme = nullptr; // Couldn't get bme280 example app to work due to arduino compat // here's a modified version // Credit to nliviu from MOS Forums for help with this // void readTimerCB(void *arg) { printf("Temperature: %.2f *C\n", s_bme->readTemperature()); // Humidity will only work on BME280, not BMP280 printf("Humidity: %.2f %%RH\n", s_bme->readHumidity()); printf("Pressure: %.2f kPa\n\n", s_bme->readPressure() / 1000.0); (void) arg; } enum mgos_app_init_result mgos_app_init(void) { s_bme = new Adafruit_BME280(); // Initialize sensor if (!s_bme->begin(SENSOR_ADDR)) { printf("Can't find a sensor\n"); return MGOS_APP_INIT_ERROR; } mgos_set_timer(2000, 1, readTimerCB, NULL); return MGOS_APP_INIT_SUCCESS; }
Grab the full source here
Conclusion
Once again, Mongoose OS makes it REALLY easy to get started, the hardest part was figuring out the I2C connections but there’s plenty of resources online for helping with that.
My plan is to have a few of these setup, 2 inside my lizard enclosure (for hot and cool sides), a few around the house (humidity would be great, had a few issues with mould) and one for outside temperature readings. The next challenge I have is understanding how I can deploy the same application to multiple devices but with different config, so I can name the MQTT topics for each board. Time to get reading! | http://www.jameselsey.co.uk/blogs/techblog/author/james-elsey/ | CC-MAIN-2018-09 | refinedweb | 542 | 66.98 |
Writing a fully customized Qt viewer (advanced)¶
Motivation¶
The
custom_viewer() function and the
CustomViewer class described in
Building Custom Data Viewers are well-suited to developing new custom viewers that
include some kind of Matplotlib plot. But in some cases, you may want to
write a Qt data viewer that doesn’t depend on Matplotlib, or may use an
existing widget. In this tutorial, we will assume that you have implemented a
Qt widget that contains the functionality you want, and we will focus on
looking at how to get it to work inside glue.
If you don’t already have an existing widget, but want to make sure it will work outside glue, start off by developing the widget outside of glue, then use the instructions below to make it usable inside glue.
Displaying the widget in glue¶
Let’s imagine that you have a Qt widget class called
MyWidget the
inherits from
QWidget and implements a specific type of visualization you
are interested in:
class MyWidget(QWidget): ...
Now let’s say we want to use this widget in glue, without having to change
anything in
MyWidget. The best way to do this is to create a new class,
MyGlueWidget, that will wrap around
MyWidget and make it
glue-compatible. The glue widget should inherit from
data_viewer (this class does a few
boilerplate things such as, for example, adding the ability to drag and drop
data onto your data viewer).
The simplest glue widget wrapper that you can write that will show
MyWidget is:
from glue.qt.widgets.data_viewer import DataViewer class MyGlueWidget(DataViewer): def __init__(self, session, parent=None): super(MyGlueWidget, self).__init__(session, parent=parent) self.my_widget = MyWidget() self.setCentralWidget(self.my_widget) # Register the viewer with glue from glue.config import qt_client qt_client.add(MyGlueWidget)
If you put the contents above into a
config.py file then launch glue in
the same folder as the
config.py file, you will then be able to go to the
Canvas menu, select New Data Viewer, and you should then be presented
with the window to select a data view, which should contain an ‘Override
This’ entry:
To give your viewer a more meaningful name, you should give your class an
attribute called
LABEL:
class MyGlueWidget(DataViewer): LABEL = "My first data viewer" def __init__(self, session, parent=None): super(MyGlueWidget, self).__init__(session, parent=parent) self.my_widget = MyWidget() self.setCentralWidget(self.my_widget)
Passing data to the widget¶
Now we want to be able to pass data to this viewer. To do this, you should
define the
add_data method which should take a single argument and return
True if adding the data succeeded, and False otherwise. So for now, let’s
simply return True and do nothing:
def add_data(self, data): return True
Now you can open glue again, and this time you should be able to load a
dataset the usual way. When you drag this dataset onto the main canvas area,
you will be able to then select your custom viewer, and it should appear
(though the data itself will not). You can now expand the
add_data method
to actually add the data to
MyWidget, by accessing
self.my_widget,
for example:
def add_data(self, data): self.my_widget.plot(data) return True
However, this will simply plot the initial data and plot more data if you drag datasets onto the window, but you will not for example be able to remove datasets, show subsets, and so on. In some cases, that may be fine, and you can stop at this point, but in other cases, if you want to define a way to interact with subsets, propagate selections, and so on, you will need to set up a glue client, which is discussed in Setting up a client. But first, let’s take a look at how we can add side panels in the dashboard which can include for example options for controlling the appearance or contents of your visualization.
Adding side panels¶
In the glue interface, under the data manager is an area we refer to as the dashboard, where different data viewers can include options for controlling the appearance or content of visualizations (this is the area indicated as C in :doc:getting-started). You can add any widget to the two available spaces.
In your wrapper class,
MyGlueWidget in the example above, you will need to
define a method called
options_widget, which returns an instantiated widget
that should be included in the dashboard on the bottom left of the glue window,
and can contain options to control the data viewer.
For example, you could do:
class MyGlueWidget(DataViewer): ... def __init__(self, session, parent=None): ... self._options_widget = AnotherWidget(...) ... def options_widget(self): return self._options_widget
Note that despite the name, you can actually use the options widget to what you
want, and the important thing is that
options_widget is the bottom left
pane in the dashboard on the left.
Note that you can also similarly define (via a method)
layer_view, which
sets the widget for the middle widget in the dashboard. However, this will
default to a list of layers which can normally be used as-is (see Using
Layers)
Setting up a client¶
Once the data viewer has been instantiated, the main glue application will call the
register_to_hub method on the data viewer, and will pass it the hub as an argument. This allows you to set up your data viewer as a client that can listen to specific messages from the hub:
from glue.core.message import DataCollectionAddMessage class MyGlueWidget(DataViewer): ... def register_to_hub(self, hub): super(MyGlueWidget, self).register_to_hub(hub) # Now we can subscribe to messages with the hub hub.subscribe(self, DataUpdateMessage, handler=self._update_data) def _update_data(self, msg): # Process DataUpdateMessage here
Using layers¶
By default, any sub-class of ~glue.viewers.common.qt.data_viewer will also include a list of layers in the central panel in the dashboard. Layers can be thought of as specific components of visualizations - for example, in a scatter plot, the main dataset will be a layer, while each individual subset will have its own layer. The ‘vertical’ order of the layers (i.e. which one appears in front of which) can then be set by dragging the layers around, and the color/style of the layers can also be set from this list of layers (by control-clicking on any layer).
Conceptually, layer artists can be used to carry out the actual drawing and
include any logic about how to convert data into visualizations. If you are
using Matplotlib for your visualization, there are a number of pre-existing
layer artists in
glue.viewers.*.layer_artist, but otherwise you will need
to create your own classes.
The minimal layer artist class looks like the following:
from glue.core.layer_artist import LayerArtistBase class MyLayerArtist(LayerArtistBase): def clear(self): pass def redraw(self): pass def update(self): pass
Essentially, each layer artist has to define the three methods shown above. The
clear method should remove the layer from the visualization, the
redraw
method should redraw the entire visualization, and
update, should update
the apparance of the layer as necessary before redrawing.
In the data viewer, when the user adds a dataset or a subset, the list of
layers should then be updated. The layers are kept in a list in the
_layer_artist_container attribute of the data viewer, and layers can be added and
removed with
append and
remove (both take one argument, which is a
specific layer artist). So when the user adds a dataset, the viewer should do
something along the lines of:
layer_artist = MyLayerArtist(data, ...) self._container.append(layer_artist) layer_artist.redraw()
If the user removes a layer from the list of layers by e.g. hitting the
backspace key, the
clear method is called, followed by the
redraw
method. | https://glueviz.readthedocs.io/en/v0.7.0/customizing_guide/full_custom_qt_viewer.html | CC-MAIN-2018-51 | refinedweb | 1,298 | 50.36 |
John Bower demonstrates more of the features of Silverlight, and Expression Blend, and shows how one might write an application that avoids UI pitfalls by placing your design responsibility squarely on your users’ shoulders. If it looks bad, it’s their fault!
Back in 1997, I had my first encounter with User Interface design while I was working for a web development company in London.
I used to watch with awe as one of our senior C++ developers spent hours every day carefully shifting his buttons and textboxes around with neurotic precision, one pixel at a time. He spent more time fiddling about with the UI of the application than actually programming the thing. He also had a tendency to swear loudly every so often and stare at co-workers with a psychotic twitch in his left eye, which I’ve since found to be a mannerism that's prevalent among many senior C++ developers.
I couldn’t help but think to myself, “it might look good to him as a programmer… but I wonder how quickly an office blood-bath would ensue if even one client emailed him saying the UI looks awful, and he wants it all different!” After all, you can’t please everyone, especially if they're customers.
My desk was the one that was closest to his, I didn't like that twitch and I was highly-strung. - I worried that I’d probably be the first to sustain collateral damage from a frenzied attack, and posthumously provide a Pollock-style splatter effect to the décor of the office. It was this bone-chilling fear of impending doom that first led me to contemplate the self-preserving benefits of a customizable User Interface.
Although Silverlight is quite capable of meeting most of your programming needs on its own, one of its common uses is simply as a front-end for a more advanced server-based application. This is where all of Silverlight’s multimedia power can be harnessed to create quite elaborate user interfaces. You could use this to make your web application feel more unique to users by allowing them to fully customize how it looks. For example: If, for whatever reason, a user found the colour Green repugnant – why would they want to use your bright Green application? Why not give them the opportunity to change it to Red? Or Purple? Or any other colour?
I wouldn't necessarily advise such a thing but it makes a useful demonstration of Silverlight's versatility, and gives us an excuse to use Expression Blend.
In this article we will create a Silverlight application that uses colour data retrieved from a Cookie in order for us to create a customizable User Interface, unique to each user.
We will cover:
For anyone who has been following this series of articles, we’re finally going to use Expression Blend! If you haven’t got Expression Blend yet, go to and download the latest preview version. As of the time of writing, it will be the December Preview.
Before we get to the drawing though, create a new Silverlight project in Visual Studio 2008. Give it a convenient name and then open the Solution Explorer.
Now we have our new blank project we can add a new User Control by right-clicking in the Solution Explorer and then selecting “Add > New Item…”
In the Add New Item window, select Silverlight User Control and enter a name for it, (I’ve cunningly called mine “button.xaml”), then click Add.
You’ll be presented with the XAML code for our blank User Control, but we won’t be editing it here. You could create your button using pure XAML code but it’s much faster, more precise, and far easier to edit it in Expression Blend.
To do this, right-click on the new Control and select “Open in Expression Blend…”
You’ll probably be asked if you want to save the project at this point. Just click the “Yes” button and Windows will start Expression Blend with the project ready to be edited.
Expression Blend makes editing XAML mercifully simple. The only problem being that Blend can appear daunting at first-glance. If you’ve previously done any graphical work in Flash, you should find it fairly easy to get your head around once you know where everything is.
If you haven’t ever used Flash, don’t worry. Although you’ll probably find it a bit tougher to grasp, it actually follows a vaguely similar layout to Visual Studio with the addition of a few graphics, and animation features.
Either way, we’ll start from the very beginning for this tutorial. You should now be presented with a window similar to this one:
Here’s a quick tour of the four main sections shown above:
Obviously I’m just scratching the surface here, there’s much more to Expression Blend’s interface than these four panes, but these are the main sections we’ll be working with for this tutorial.
For the purposes of our project, let’s make a funky glass button using a few Path layers and some transparent gradients.
The first thing we need to do is specify the size of the button. Click on the White area in the Preview pane. This is our Control’s Canvas, and you should notice that clicking it selects the relevant section of XAML code and also the “[Canvas]” layer in the Objects and Timeline pane.
Click on the Properties tab and find the Layout category. Then change the Width and Height properties to 250, and 100 respectively. As our button will have rounded edges it’s a good idea to make the Canvas transparent allowing the background of the application show through, so drag the A (alpha) slider down to 0% in the colour editor.
Setting the Opacity for our Canvas will affect all its child objects, so make sure it’s left on 100%. You could use this parameter to fade the Control in and out if you wanted to, but let’s not go too crazy just yet.
Ok, let’s start drawing. Click the Rectangle tool from the tool box on the left-hand side of the screen and draw it into the preview window, making sure you leave a bit of blank space round the edges. In the top-left corner of the rectangle there are two anchor points which you can drag in order to round-off the corners.
The rounding effect is specified by the RadiusX and RadiusY properties in the Appearance category so as you drag the anchor points they will both change automatically. The alternative, of course, is to type the values in manually.
When you’re happy with the roundness of your corners select a nice garish red colour for the background, and keep the Stroke, (outline), colour as Black.
This is the Rectangle we will change the colour of in our application, so we also need to give it a name to refer to later. At the top of the property pane change the Name property from “<No Name>” to “btnBG”.
Excellent! Now it’s time to get all arty and create the glass effect using gradients. Aesthetically, this section of the tutorial is completely up to you as long as you follow a few basic rules; but we’ll get to them in a sec.
Copy and paste the rectangle you’ve just created, change the Stroke alpha to 0%, and select Gradient as the fill type.
You can add colours to the gradient by clicking on the gradient bar underneath the colour square, and then dragging them along to edit the transitions between them. Just make sure you only use White and Black so we don’t end up with a button that looks strange when we change its background colour later. Each colour you add can have independent alpha values for transparency.
I made a gradient going from semi-transparent Black, to fully-transparent White, and then reduced the Rectangle’s overall Opacity to 77%.
Now let’s create a layer to give the button a highlight. Copy and paste the last rectangle you made and edit the gradient again. Then fade it out a lot more using the Opacity slider and alpha values.
Don’t worry if it doesn’t look that great. The secret to being a good graphic designer is to assume that everything you do is brilliant no matter how bad it actually looks.
When you’re happy with your button hit CTRL+S to save the project and then go back to Visual Studio. You should be confronted with a message box telling you that some of the project files have changed and asking if you would like to reload them. Just click “Yes”, and we’re ready for some programming.
I won’t go into too much detail about Cookies here because we’d be digressing from the main topic too much. All we need to do is create three Cookies that store colour information. This will be the colour Silverlight will use for our button Control. We’ll also create three text boxes in a moment so we can specify which one we want for our application. For the purposes of this demonstration, we'll set the cookies to be ephemeral. We'll set the expiry to be tomorrow. If you were doing it for real, you'd want something a lot more permanent!
Rename “TestPage.html” to “TestPage.asp” and add the following lines of code above the <html> tag:
<%
Dim r, g, b
Dim r2, g2, b2
response.cookies("BtnColorR").Expires=date+1
response.cookies("BtnColorG").Expires=date+1
response.cookies("BtnColorB").Expires=date+1
r2 = Request.QueryString("rIn")
g2 = Request.QueryString("gIn")
b2 = Request.QueryString("bIn")
if r2 <> "" and g2 <> "" and b2 <> "" then
response.cookies("BtnColorR")=r2
response.cookies("BtnColorG")=g2
response.cookies("BtnColorB")=b2
end if
r=request.cookies("BtnColorR")
g=request.cookies("BtnColorG")
b=request.cookies("BtnColorB")
if r="" or g="" or b="" then
response.cookies("BtnColorR")=0
response.cookies("BtnColorG")=0
response.cookies("BtnColorB")=0
r=0
g=0=0=0=0
b=0
%>
When that’s done, save the file.
Again, this is quite simple. We just need to create a standard HTML form with three text boxes, one submit button, and three hidden form elements.
Open “TestPage.asp” again, and add these lines of code within the <body> tags:
<form action="TestPage.asp">
<input type="text" name="rIn" value="<%=r%>">
<input type="hidden" id="r" value="<%=r%>">
<input type="text" name="gIn" value="<%=g%>">
<input type="hidden" id="g" value="<%=g%>">
<input type="text" name="bIn" value="<%=b%>">
<input type="hidden" id="b" value="<%=b%>">
<input type="submit" value="Save Colour">
</form>
Save the file, and we’re done with Cookies.
The hidden form elements will be the ones our application reads when it loads to get the colour for the button. The text boxes will allow us to specify which colour values we want, and they’ll be saved to our Cookies when the user hits the submit button.
This is actually a very similar process to the one we used for our High-Speed Loop in my previous article, so if you get lost here you should probably read through that one before continuing.
In order to create our button object, we first declare a variable using the New keyword. Open “Page.xaml.vb” and add the following line:
Dim btnControl As New button
The button type is a direct reference to our “button.xaml” file. If you called your User Control something other than “button.xaml”, you’ll have to change this accordingly.
We then need to set up a variable to point to our main Canvas object.
Dim pCanvas As Canvas
Now we have our variables, we need to alter the Page_Loaded function to add our button to the Canvas when the application loads. Find the Page_Loaded function and add the following highlighted lines of code:
Public Sub Page_Loaded(ByVal o As Object, ByVal e As EventArgs)
' Required to initialize variables
InitializeComponent()
' set pCanvas to our root canvas object
pCanvas = FindName("parentCanvas")
' add our control to the canvas
pCanvas.Children.Add(btnControl)
End Sub
Once that’s done, save the file.
We’ve already covered updating Silverlight object parameters in the previous two articles, so I’ll try to avoid repeating myself again. All we need to do is set the colour parameter for the button UI object we created in Expression Blend. To do this, we’ll create sub-routines within the button object so we don’t clutter up the main section of code for the application.
Expand “button.xaml” in the Solution Explorer, if it isn’t already, and then open “button.xaml.vb”. Then add a variable we can use to point to our background rectangle.
Dim bg As Rectangle
We’ll also need three Byte variables to store the colour the button should be:
Public r, g, b As Byte
Next, let’s write a sub routine that does our colour changing. The Colour change method we’ll create will take 4 byte values and use them to change the Rectangle.FillProperty value of bg.
Private Sub ChangeBG(ByVal a As Byte, ByVal r As Byte, ByVal g As Byte, ByVal b As Byte)
bg.SetValue(Rectangle.FillProperty, Color.FromArgb(a, r, g, b))
We’ve made this sub routine public so we can call it from “Page.xaml” later.
To create a MouseOver event, to apply our colour change, let’s create two new functions. The first one is called mOver, and the second is called mOut.
Private Sub mOver(ByVal o As Object, ByVal e As EventArgs)
' change the fill colour of the BG rectangle
ChangeBG(255, r, g, b)
Private Sub mOut(ByVal o As Object, ByVal e As EventArgs)
ChangeBG(255, 0, 0, 0)
mOverchanges the colour of our button to the values of our r, g, and b variables. mOut returns it to Black when the mouse leaves the button.
Something to watch out for when developing Silverlight applications is the order in which functions are called. At certain points of the loading process you will find that some methods return an error, simply because the object you’re trying to reference doesn’t exist yet. The easiest way to get around this is to use the “Loaded” property on the object you want to work with, and use it to call a function that will only work when that object has been created.
Let’s create a sub routine that will point our bg variable to the rectangle we need to change the colour of, and then call our Colour change function to make our background rectangle Black when the application starts:
Private Sub bgLoad(ByVal sender As Object, ByVal e As EventArgs)
' set bg to the rectangle that called this sub
bg = sender
The sender parameter will point to the object that called this sub routine. In this case it will be the rectangle we want to change the colour of. For this to work, we now add a Loaded parameter to our rectangle in “button.xaml”.
Open “button.xaml” and find the first rectangle tag inside the Canvas tags. Then add the following highlighted segment of code:
<Rectangle Loaded="bgLoad" Width="234" Height="84" Fill="#FFFF0000" Stroke="#FF000000" Canvas.
Now find the last rectangle tag in the Canvas and add the following highlighted bit of code:
<Rectangle MouseEnter="mOver" MouseLeave="mOut" Opacity="0.51" Width="234" Height="84" Stroke="#00000000" RadiusX="11.5" RadiusY="11.5" Canvas.
<t;Rectangle.Fill>
<LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
<GradientStop Color="#FF000000" Offset="0"/>
<GradientStop Color="#FFFFFFFF" Offset="0.174"/>
<GradientStop Color="#00FFFFFF" Offset="1"/>
</LinearGradientBrush>
</Rectangle.Fill>
</Rectangle>
Hit F5 and see what happens.
Your button should be displayed in the top-left hand corner of the application, and it should be Black! Move your Mouse cursor over the button and it will remain Black… for now.
Now the button is being displayed, we just need to pass the data from our ASP page to Silverlight and we’re good to go.
Well… to be more precise, we’ll suck the data from the page using the HtmlDocument and HtmlElement objects from within Silverlight.
To do this we need to first Import the System.Windows.Browser namespace. So, open up “Page.xaml.vb” and add the following line to the very top of the file:
Imports System.Windows.Browser
Then we need to create a variable that will point to our application’s host document:
Dim document As HtmlDocument
We nearly have full access to the document and all the elements within it. We only need three elements though: The Red, Green, and Blue hidden form elements we created earlier. Once we are able to access those we need to populate the public r, g, and b variables within our button.
Add the following highlighted lines of code to the Page_Loaded function:
document = HtmlPage.Document
Dim rElement As HtmlElement = document.GetElementByID("r")
Dim gElement As HtmlElement = document.GetElementByID("g")
Dim bElement As HtmlElement = document.GetElementByID("b")
btnControl.r = rElement.GetAttribute("value")
btnControl.g = gElement.GetAttribute("value")
btnControl.b = bElement.GetAttribute("value")
Setting the document variable to HtmlPage.Document opens up the host page for us to read through and get data from. For each of the three elements we’re interested in, (r, g, and b), we need to get the value attribute and populate our button’s r, g, and b variables.
Now, when you run the application, you will be able to specify and store the colour you want the button to change to when you move your mouse over it!
Changing the colour parameters for one button object is just the tip of an extremely large iceberg. Obviously, You could store all sorts of information, in various ways, and subsequently change any number of properties allowing your users to create their most comfortable working environment. Your users could have a field-day customising the entire look of the application; be it position, colour, or style.
Your application could well become your company’s equivalent to MySpace™; a veritable treasure-trove of elaborately awful design layouts.It’s completely up to them and, more importantly, you can’t be blamed for it!
More importantly, I hope I've shown how easy it is to use Expression Blend in the design of your application. Hopefully, there will be fewer hours spent obsessively moving buttons around the screen!
If you would like to see this project in action, go to: all the source code, in both VB and C#, is in the speechbubble at the top of the article.
Author profile: John Bower
John Bower spent six years as Lead Web Designer at FreshEgg before getting an MA in 3D Computer Animation at the National Centre of Computer Animation, UK. He is now running DeepSpaceObjects consultancy, specialising in Flash Development and has contributed to a number of celebrity and business websites. | http://www.simple-talk.com/dotnet/.net-framework/silverlight-skinnable-user-interfaces/ | crawl-002 | refinedweb | 3,189 | 60.85 |
Posts Tagged ‘whoosh’ 2)
In this series I’ll show you how to build a search engine using standard Python tools like Django, Whoosh and CouchDB. In this post we’ll begin by creating the data structure for storing the pages in the database, and write the first parts of the webcrawler.
CouchDB’s Python library has a simple ORM system that makes it easy to convert between the JSON objects stored in the database and a Python object.
To create the class you just need to specify the names of the fields, and their type. So, what do a search engine need to store? The url is an obvious one, as is the content of the page. We also need to know when we last accessed the page. To make things easier we’ll also have a list of the urls that the page links to. One of the great advantages of a database like CouchDB is that we don’t need to create a separate table to hold the links, we can just include them directly in the main document. To help return the best pages we’ll use a page rank like algorithm to rank the page, so we also need to store that rank. Finally, as is good practice on CouchDB we’ll give the document a type field so we can write views that only target this document type.
class Page(Document): type = TextField(default="page") url = TextField() content = TextField() links = ListField(TextField()) rank = FloatField(default=0) last_checked = DateTimeField(default=datetime.now)
That’s a lot of description for not a lot of code! Just add that class to your models.py file. It’s not a normal Django model, but we’re not using Django models in this project so it’s the right place to put it.
We also need to keep track of the urls that we are and aren’t allowed to access. Fortunately for us Python comes with a class, RobotFileParser which handles the parsing of the file for us. So, this becomes a much simpler model. We just need the domain name, and a pickled RobotFileParser instance. We also need to know whether we’re accessing an http or https and we’ll give it type field to distinguish it from the Page model.
class RobotsTxt(Document): type = TextField(default="robotstxt") domain = TextField() protocol = TextField() robot_parser_pickle = TextField()
We want to make the pickle/unpickle process transparent so we’ll create a property that hides the underlying pickle representation. CouchDB can’t store the binary pickle value, so we also base64 encode it and store that instead. If the object hasn’t been set yet then we create a new one on the first access.
def _get_robot_parser(self): if self.robot_parser_pickle is not None: return pickle.loads(base64.b64decode(self.robot_parser_pickle)) else: parser = RobotFileParser() parser.set_url(self.protocol + "://" + self.domain + "/robots.txt") self.robot_parser = parser return parser def _set_robot_parser(self, parser): self.robot_parser_pickle = base64.b64encode(pickle.dumps(parser)) robot_parser = property(_get_robot_parser, _set_robot_parser)
For both pages and robots.txt files we need to know whether we should reaccess the page. We’ll do this by testing whether the we accessed the file in the last seven days of not. For Page models we do this by adding the following function which implements this check.
def is_valid(self): return (datetime.now() - self.last_checked).days < 7
For the RobotsTxt we can take advantage of the last modified value stored in the RobotFileParser that we’re wrapping. This is a unix timestamp so the is_valid function needs to be a little bit different, but follows the same pattern.
def is_valid(self): return (time.time() - self.robot_parser.mtime()) < 7*24*60*60
To update the stored copy of a robots.txt we need to get the currently stored version, read a new one, set the last modified timestamp and then write it back to the database. To avoid hitting the same server too often we can use Django’s cache to store a value for ten seconds, and sleep if that value already exists.
def update(self): while cache.get(self.domain) is not None: time.sleep(1) cache.set(self.domain, True, 10) parser = self.robot_parser parser.read() parser.modified() self.robot_parser = parser self.store(settings.db)
Once we’ve updated the stored file we need to be able to query it. This function just passes the URL being tested through to the underlying model along with our user agent string.
def is_allowed(self, url): return self.robot_parser.can_fetch(settings.USER_AGENT, url)
The final piece in our robots.txt puzzle is a function to pull the write object out of the database. We’ll need a view that has the protocol and domain for each file as the key.
@staticmethod def get_by_domain(protocol, domain): r = settings.db.view("robotstxt/by_domain", key=[protocol, domain])
We query that mapping and if it returns a value then we load the object. If it’s still valid then we can return right away, otherwise we need to update it.
if len(r) > 0: doc = RobotsTxt.load(settings.db, r.rows[0].value) if doc.is_valid(): return doc
If we’ve never loaded this domain’s robots.txt file before then we need to create a blank object. The final step is to read the file and store it in the database.
else: doc = RobotsTxt(protocol=protocol, domain=domain) doc.update() return doc
For completeness, here is the map file required for this function.
function (doc) { if(doc.type == "robotstxt") { emit([doc.protocol, doc.domain], doc._id); } }
In this post we’ve discussed how to represent a webpage in our database as well as keep track of what paths we are and aren’t allowed to access. We’ve also seen how to retrieve the robots.txt files and update them if they’re too old.
Now that we can test whether we’re allowed to access a URL in the next post in this series I’ll show you how to begin crawling the web and populating our database.
Photo of Celery, Carrots & Sweet Onion for Chicken Feet Stock by I Believe I Can Fry.
Beating Google With CouchDB, Celery and Whoosh (Part 1)
Ok, let’s get this out of the way right at the start – the title is a huge overstatement. This series of posts will show you how to create a search engine using standard Python tools like Django, Celery and Whoosh with CouchDB as the backend.
Celery is a message passing library that makes it really easy to run background tasks and to spread them across a number of nodes. The most recent release added the NoSQL database CouchDB as a possible backend. I’m a huge fan of CouchDB, and the idea of running both my database and message passing backend on the same software really appealed to me. Unfortunately the documentation doesn’t make it clear what you need to do to get CouchDB working, and what the downsides are. I decided to write this series partly to explain how Celery and CouchDB work, but also to experiment with using them together.
In this series I’m going to talk about setting up Celery to work with Django, using CouchDB as a backend. I’m also going to show you how to use Celery to create a web-crawler. We’ll then index the crawled pages using Whoosh and use a PageRank-like algorithm to help rank the results. Finally, we’ll attach a simple Django frontend to the search engine for querying it.
Let’s consider what we need to implement for our webcrawler to work, and be a good citizen of the internet. First and foremost is that we must be read and respect robots.txt. This is a file that specifies what areas of a site crawlers are banned from. We must also not hit a site too hard, or too often. It is very easy to write a crawler than repeatedly hits a site, and requests the same document over and over again. These are very big no-noes. Lastly we must make sure that we use a custom User Agent so our bot is identifiable.
We’ll divide the algorithm for our webcrawler into three parts. Firstly we’ll need a set of urls. The crawler picks a url, retrieves the page then store it in the database. The second stage takes the page content, parses it for links, and adds the links to the set of urls to be crawled. The final stage is to index the retrieved text. This is done by watching for pages that are retrieved by the first stage, and adding them to the full text index.
Celery’s allows you to create ‘tasks’. These are units of work that are triggered by a piece of code and then executed, after a period of time, on any node in your system. For the crawler we’ll need two seperate tasks. The first retrieves and stores a given url. When it completes it will triggers a second task, one that parses the links from the page. To begin the process we’ll need to use an external command to feed some initial urls into the system, but after that it will continuously crawl until it runs out of links. A real search engine would want to monitor its index for stale pages and reload those, but I won’t implement that in this example.
I’m going to assume that you have a decent level of knowledge about Python and Django, so you might want to read some tutorials on those first. If you’re following along at home, create yourself a blank Django project with a single app inside. You’ll also need to install django-celery, the CouchDB Python library, and have a working install of CouchDB available.
Photo of celery by Judy **.. | https://andrewwilkinson.wordpress.com/tag/whoosh/ | CC-MAIN-2017-17 | refinedweb | 1,652 | 73.17 |
STAMP DUTY ON SHARES AND ITS EFFECT ON SHARE PRICES
- Alexandrina Sanders
- 2 years ago
- Views:
Transcription
1 STAMP UTY ON SHARES AN ITS EFFECT ON SHARE PRICES Steve Bond Mke Hawkns Alexander Klemm THE INSTITUTE FOR FISCAL STUIES WP04/11
2 STAMP UTY ON SHARES AN ITS EFFECT ON SHARE PRICES Steve Bond (IFS and Unversty of Oxford) Mke Hawkns (IFS) Alexander Klemm (IFS and UCL)* June 004 Abstract: Ths paper provdes a dscusson of stamp duty and ts effects. Ths s followed by an emprcal study usng changes n the rate of stamp duty n the UK as natural experments. Because shares wll be affected dfferently dependng on how frequently they are traded, we can employ a dfference-n-dfferences methodology. We fnd that the announcements of cuts n stamp duty had a sgnfcant and postve effect on the prce of more frequently traded shares compared to other shares. As expected under the effcent markets hypothess, the mplementaton of cuts (when at a dfferent date from the announcement) dd not affect returns dfferentally. Key words: Stamp duty, transacton tax, Tobn-tax, natural experment, tax reform. JEL classfcaton: G14, H9, E6. Acknowledgments: Ths research s part of the Large Busness Taxaton Programme at the IFS, funded by the 100 Group and the Inland Revenue. We would lke to thank Paula Landow, Julan McCrae and semnar partcpants at an Inland Revenue semnar, especally Stephen Matthews, for comments and advce. Any remanng errors are solely the responsblty of the authors. * Correspondng author: e-mal: postal address: Insttute for Fscal Studes, 7 Rdgmount Street, London WC1E 7AE, UK.
3 Executve Summary Stamp duty s a tax on share transactons n UK ncorporated companes, currently leved at ½% of the purchase prce of shares. Ths rate has been changed over the years, most recently n 1986 when t was cut from 1% to ts current rate. In the 1990 Budget the Conservatve government of the tme announced ts abolton to concde wth the ntroducton of the London Stock Exchange s new settlements system, Taurus. However, ths was never mplemented and stamp duty remans. ebate contnues about whether stamp duty on shares should be abolshed, and t s therefore useful to examne some emprcal evdence on ts effects. If stamp duty s captalsed nto share prces, t s expected to depress prces more for shares that are more frequently traded, and where future stamp duty payments are expected to be hgher at any gven rate. Past announcements of cuts n the rate of stamp duty allow us to test ths predcton, by studyng the effect of these announcements on share prces for groups of frms wth dfferent levels of tradng. ata on tradng volumes n the 1990s shows that frm sze s a good predctor of share turnover rates. As ths data on tradng volumes s not avalable pror to 1986, our man results use frm sze as a proxy for turnover. We also use data on actual turnover rates to check our results for the 1990 announcement of abolton. We fnd evdence that stamp duty ndeed has a detrmental effect on share prces. Specfcally, the prce of shares that are more frequently traded ncreases relatvely to that of shares that are less frequently traded on the announcement dates of cuts n stamp duty n 1984, 1986 and The analyss of the events n 1986 s of partcular nterest, because n that year the actual cut took place around sx months after the announcement. We fnd a sgnfcant effect only on the announcement date, not on the date of the mplementaton. Ths s the expected result n an effcent market, and provdes some support for our emprcal approach. Stamp duty s thus shown to depress share prces, partcularly for frms whose shares are frequently traded..
4 1 Introducton Ths paper nvestgates the mpact of UK stamp duty on share prces. Beng a transacton tax, stamp duty on shares s controversal. Research on the effects of transacton taxes s therefore polcy relevant. Not only because of the potentally large effect on stock markets, but also because of the wder dscusson about the merts of ntroducng a transacton tax on nternatonal currency transactons (the Tobn tax ). 1 For all the theoretcal arguments on the effects of stamp duty, there s surprsngly lttle emprcal evdence on the effects of stamp duty on share prces and turnover. The lttle that exsts s summarsed n secton 3.. Our approach s to use changes n the rate of stamp duty as natural experments. In partcular, we use a dfference-n-dfferences methodology, comparng the dfferental mpact on the prce of low turnover and hgh turnover shares of the announcements and mplementatons of stamp duty reductons n 1984, 1986 and Ths paper s structured as follows. The next secton descrbes the background of the current stamp duty regme and the changes made to t. Secton 3 descrbes the theory of a transacton tax and brefly revews the emprcal evdence. Secton 4 explans our emprcal strategy to dentfy effects on share prces usng tax reforms. Secton 5 presents the results and secton 6 concludes. An appendx dscusses the effect of market movements on our results, and whether usng abnormal returns would be approprate n ths context. Background Stamp duty s a tax on share transactons n UK ncorporated companes, currently leved at ½% of the purchase prce of shares. It s chargeable whether the transacton takes place n the UK or 1 The Tobn tax was frst suggested n Tobn (1974). Strctly, stamp duty s chargeable on the purchase prce of a share where there s a legal nstrument of transfer. Ths accounted for around 10% of total revenue from share transactons n The remanng revenue was collected through stamp duty reserve tax (SRT), whch s the equvalent tax on an agreement to transfer the share where there s no wrtten nstrument of transfer. Snce the ntroducton of an electronc settlements system, CREST, n 1996, SRT has taken over as the man tax on share transactons. 3
5 overseas, and whether ether party s resdent n the UK or not. It s not chargeable on securtes ssued by companes ncorporated overseas. The rate of stamp duty has changed over the years. Before 1974 t stood at 1%. Then t was ncreased to %. In the 1984 Budget t was reduced to 1% agan. In 1986 t was further reduced to ts current rate of ½%. In the 1990 Budget the Conservatve government of the tme announced that stamp duty on shares would be abolshed wth the ntroducton of the London Stock Exchange s new settlements system, Taurus. However, n the end Taurus was abandoned n March 1993 and the abolton was never mplemented. One of the outstandng features of stamp duty s that t s the cheapest of all UK taxes to collect, wth a collecton cost of just 0.11 pence per pound rased. For comparson, the correspondng fgure for ncome tax, the most mportant revenue raser, s 1.59 pence (Inland Revenue, 00). As the fgure reported for stamp duty ncludes the cost of collectng stamp duty from land and property purchases, t s lkely that the correspondng fgure for stamp duty on share transactons s even lower, gven that most transactons on the stock exchange are now electronc and stamp duty can thus be deducted automatcally. The amount of revenue rased vares from year to year around an average of about 3bn, 3 whch corresponds roughly to one tenth of that rased by corporaton tax. Whle stamp duty s n law leved on the purchaser of a share n a UK regstered company, the true economc ncdence of the tax, and therefore ts effect on the economy, s ambguous. In the long run, ndvduals wll bear the tax ether n lower returns on ther savngs, hgher product prces due to lower nvestment, or a combnaton of the two. At the moment of ntroducton or unantcpated ncrease, the tax may fall predomnantly on exstng shareholders f share prces adjust to delver the same expected post-tax returns as are avalable on substtute assets that are not subject to stamp duty. Therefore the benefcares of a cut n stamp duty are also most lkely to be the current owners of shares that are lable to stamp duty. 3 Accordng to Inland Revenue Statstcs, stamp duty on shares rased the followng amounts durng the last fve years:.5bn (1998/99), 3.7bn (1999/000), 4.5bn (000/01),.9bn (001/0) and.5bn (00/03). 4
6 In recent years there has been ncreasng pressure from the London Stock Exchange and others for the abolton of stamp duty. 4 One of the prncpal arguments used to support ts abolton s that stamp duty rases the cost of captal for UK frms and therefore reduces nvestment. In ts calculatons for the London Stock Exchange, OXERA (001) estmated that stamp duty rases the cost of captal by 0.7 to 0.87 percentage ponts. Ths s calculated by dervng the mpled mpact of stamp duty on share prces and therefore company dscount rates. In practce, the effect on nvestment may depend on the margnal source of fnance for dfferent types of frms. For frms whose margnal source of fnance s retaned earnngs or new equty, we would ndeed expect stamp duty to rase the cost of captal. Ths s because t s leved on the share prce, whch ncludes the captalsed value of retaned profts that have not yet been pad out to shareholders. Hawkns and McCrae (00) calculate that stamp duty at ts current rate could add between 0.15 and 0.65 percentage ponts to the cost of retaned earnngs fnance, dependng on the frequency wth whch a company s shares are bought and sold. For other frms,.e. those whose margnal source of fnance s debt, the effect on ther cost of captal may be less mportant. 3 Economc effects of securtes transactons taxes The potental effects of stamp duty are wde-rangng. It may affect share prces, as nvestors wll prce n future payments of ths transacton tax. It may also affect tradng volumes, as the dfference between the valuaton of a prospectve buyer and seller needs to be larger to cover not only general transacton costs, but also the amount of stamp duty. 5 Furthermore there may be effects on volatlty, whch could be reduced f the latter effect prevented tradng when valuatons change only margnally, although t may also ncrease, because adjustments wll take 4 E.g. London Stock Exchange Urgent acton on Stamp uty needed to boost the economy Press Release 4 March 003. See also Stamp Out Stamp uty Campagn at 5 Emprcal evdence has consstently found such a negatve relatonshp, see Jackson and O onnell (1985), Lndgren and Westlund (1990), Ercsson and Lndgren (199), Atken and Swan (000) and Swan and Westerholm (001) 5
7 place more suddenly. 6 Whle all of these effects may be mportant, the focus of ths paper s on the effect on the share prce. 3.1 Theoretcal mpact of a transactons tax on share prces Accordng to the standard dvdend valuaton model, 7 the equlbrum prce of a share should be equal to the expected present dscounted value of future dstrbutons after all taxes. In the specal case where the dvdend per share grows at the constant rate g and the dscount rate r s also constant, the prce P s gven n the absence of transacton taxes by: ( 1+ g) ( 1+ r) ( 1+ g) + = 3 ( 1+ r) r g P = r where s the dvdend per share pad at the end of the current perod, and r - g s the dvdend yeld. Stamp duty can be ncorporated nto ths smple model by assumng a fxed number of transactons t per perod, so that the prce n the presence of stamp duty becomes: = r g + st ( stp)( 1+ g) ( 1+ r) ( stp)( 1+ g) 3 ( 1+ r) stp P = = 1+ r stp r g where s s the rate of stamp duty. To calculate the effect of an unantcpated permanent change n the rate of stamp duty, we make the addtonal assumptons that the change n the stamp duty rate does not affect turnover, the dscount rate or the growth rate of dvdends. The proportonal change n prce mpled by a P P ( s s ) t change n the rate of stamp duty from s to s s then gven by: =. P r g + s t 6 Emprcal evdence on the effect on volatlty has been rather mxed. Umlauf (1993) and Saporta and Kan (1997) found no effect, Atken and Swan (000) and Swan and Westerholm (001) found that transactons taxes tend to ncrease volatlty and Hau and Chevaller (000) found that they slghtly reduce t. 7 See, e.g. Brealey and Myers (000). 6
8 t In the specal case of the abolton of stamp duty (s = 0), ths smplfes to s and the r g assumpton that stamp duty has no effect on share turnover becomes unnecessary. Table 1 shows the ncrease n share prces predcted by ths smple model f the current stamp duty rate of 0.5% were to be abolshed, for a range of shares wth dfferent turnover rates and dvdend yelds. The hgher the frequency of transactons, the more stamp duty would be saved n the future by shareholders as a result of ts abolton, and the hgher s the predcted ncrease n the current share prce. Ths basc predcton holds for cuts n the rate of stamp duty more generally, provded the turnover rate ncreases less than proportonately as the rate of stamp duty s reduced. 8 Ths s the key predcton that we test n our emprcal analyss. Table 1: Predcted share prce mpact of abolshng stamp duty vdend Turnover yeld 10% 30% 50% %.5% 7.5% 1.5% 3% 1.7% 5.0% 8.3% 4% 1.3% 3.8% 6.3% In practce, there are a number of reasons why the observed prce mpact of abolshng stamp duty could dffer from that predcted by ths smple model. For nstance, nvestors may not expect the abolton to be permanent, whch would reduce the predcted mpact on prce. In cases where the rate s cut rather than abolshed, an ncrease n turnover would partally offset the effect of the lower tax rate on prce, although ths n turn may produce an offsettng effect through market lqudty. That s, nvestors may requre a lower rsk premum from shares that are traded n a more lqud market, whch would tend to reduce the dscount rate, r. We would also expect many factors other than the rate of stamp duty to affect a company s share prce. In prncple, any news that affected nvestors expectatons of future profts, or ther expected post-tax return on other assets (real dscount rate), would potentally change the share prce. Examples of such news mght nclude announcements of recent profts or updated analysts forecasts of future profts, changes n macroeconomc polcy that may affect future real 8 That s, provded a 50% reducton n the rate of stamp duty, from say 0.5% to 0.5%, would not produce a 50% ncrease n the number of transactons. 7
9 nterest rates or the volatlty of nflaton, or a new nventon that changed the relatve cost of a company or opened up a new market for ts products. The emprcal challenge s to dentfy the effect of a stamp duty rate change gven that there are so many other nfluences on share prces. 3. Revew of emprcal evdence The followng provdes a bref revew of both UK and nternatonal emprcal work on the effects of stamp duty or equvalent foregn transactons taxes Evdence from the UK espte the changes n stamp duty tax rates and the debate surroundng them, there s not very much UK emprcal work. Jackson and O onnell (1985) estmate the mpact of transacton costs on average real share prces over the perod usng aggregate annual data for the UK stock market. They fnd an elastcty of share prce wth respect to transacton costs of 0.3. If true, ths mples that the 1984 reducton n the stamp duty rate from % to 1% would have led to an 8% rse n share prces. 9 Saporta and Kan (1997) look at the share prce mpact of changes n the rates of stamp duty by observng share prce movements on the days that the last three rate changes were announced n the UK n 1974, 1984 and They fnd that share prces moved n the expected drecton and by a statstcally sgnfcant amount. However, as noted by Saporta and Kan, the change cannot be drectly attrbuted to changes n stamp duty, because other nformaton may have been httng the market on the same day, partcularly as the announcements were made on budget days Jackson and O onnell estmate that other transacton costs were 0.75% of transacton values. Ths mples that total transacton costs were.75% pror to the stamp duty cut n The effect of a 1 percentage pont cut n stamp duty on prces can then be calculated as the share prce elastcty tmes the percentage change n transacton costs,.e. 0.3 (1%/.75%)= 8.4%. 10 They also try to learn somethng from comparng the mpact on shares traded n the UK and stamp duty free Amercan epostory Recepts (AR). Ths s made dffcult by arbtrage, whch wll lead to smlar prces between the two assets. Nevertheless ther results are as expected (.e. returns on ARs are hgher after announcements of tax cuts) but ths dfference s not sgnfcant. Because of very small sample szes (between 4 and 11 frms) they should anyway be treated wth cauton. 8
10 3.. Overseas evdence Related evdence has also been presented for other countres. Umlauf (1993) employs a smlar methodology to that n Saporta and Kan to consder the effect of the mposton of a 1% tax on Swedsh share transactons n He fnds that the share prce ndex declned by 5.3% durng the month of the announcement, compared wth a predcted 6.75% declne. However, hs paper s subject to the same crtcsm as Saporta and Kan s namely, that t fals to control for other possble nfluences on share prces such as nterest rate changes and other tax changes. Swan and Westerholm (001) attempt to dentfy the share prce mpact of the abolton of securtes transacton taxes n Sweden and Fnland n 1991 and 199 respectvely. In order to allow ncreases n turnover due to lower transacton costs to have an addtonal postve mpact on share prces through mprovements n lqudty, they frst model the effects on share turnover of changes n transacton costs due to tax changes. They use pooled daly data for roughly a twoyear perod ether sde of the tax change for 30 Fnnsh stocks and 80 Swedsh stocks. They attempt to correct for other nfluences on share prces by ncludng control varables such as nterest rates and exchange rates. They also estmate equvalent aggregate equatons for the whole market and separate equatons for dfferent sub-samples of stocks. Ths allows them to test whether transacton taxes mpact dfferentally on turnover of stocks n small and large companes, whch may dffer n terms of lqudty and other transacton costs. They estmate that the elastcty of share prces wth respect to transacton costs s 0.0 for Sweden and 0.1 for Fnland. These are smlar magntudes to those found by Jackson and O onnell for the UK. If the true elastcty for the UK s around 0. and transacton costs are between 1% and 3% of transacton values, ths mples that a 0.5% cut n stamp duty would ncrease share prces by between 3.5% and 14% a smlar range to that presented n Table 1. 4 Methodology We follow a dfferent approach to the exstng lterature by usng a dfference n dfferences approach, n whch we use changes n stamp duty rates over tme, and announcements thereof, as natural experments. Specfcally, from the smple model of share prces outlned above, we would expect the prce mpact of a gven change n the rate of stamp duty to be greater for stocks 9
11 that have hgh turnover than for those wth low turnover, other thngs beng equal. By splttng stocks nto hgh and low turnover categores, n prncple ths enables us to test whether stamp duty does ndeed affect share prces n the way predcted by the model. 4.1 Econometrc specfcaton The approach that we start wth s a basc dfference-n-dfferences specfcaton, as follows: r = α + β 1 + β + u t 1 t where r t s the rate of return on a share at tme t, random error. 1 and are dummy varables and u t s a There may be more than two dummes, but they wll always be defned n the same manner: whenever 1 equals one, wll also equal one,.e. determnes the addtonal effect of beng n group for frms that are already n group 1. E.g. when frms are grouped accordng to sze, 1 wll be one for all frms above a certan sze and even hgher sze threshold. wll be one for all frms above an The coeffcents are then nterpreted as follows. α wll be the average return on all shares not n a group defned by one of the dummes. β 1 gves the addtonal return on shares, whch are n that group defned by 1, compared to the control group of shares not defned by ether of the dummes. β wll gve the addtonal return on shares that are n the group defned by only, relatve to all the shares n the group defned by 1. The sum of β 1 and β would thus be the addtonal return of shares n the group defned by relatve to shares not n We measure r t as the cumulatve total return over the perod (event wndow). Ths ncludes both dvdends and captal gans, although n most cases there are no dvdend payments durng the relatvely short event wndows
12 4. Events consdered The four events that we use as natural experments are the three announcements of stamp duty cuts n the Budgets of 1984, 1986 and 1990, and the mplementaton of the 1986 cut sx months after ts announcement. If the stock market were reasonably effcent, n the sense that new nformaton about or affectng a frm s valuaton s reflected n ts share prce soon after t s revealed to the market, we would expect the man effect of a stamp duty cut on share prces to take place mmedately after the announcement date. There should be no effect on the date of the mplementaton. In practce, the dates of announcement and mplementaton were the same n In 1986, the rate cut was announced before t was mplemented although there was some uncertanty surroundng the precse date of mplementaton, as t was to concde wth the Bg Bang. 11 The fnal event consdered was John Major s announcement n Budget 1990 that stamp duty would be abolshed wth the ntroducton of Taurus. 1 Ths proposal was never actually mplemented, as the Taurus project was eventually abandoned. Hence, f the ntal announcement had any credblty we would expect share prces to adjust n March 1990, after whch pont the effect would presumably unwnd as t became clear to market partcpants that Taurus would never become operatonal. The detals of the three announcements and the subsequent mplementatons of the rate cuts are summarsed n Table below. Table : Key dates and detals of stamp duty rate changes Announcement date Implementaton date Actual mplementaton date Old rate New rate announced 13 March March March 1984 % 1% 18 March 1986 Autumn October % ½% 0 March 1990 Late n 1991/9 (1) Not mplemented ½% 0% (1) The Budget costng assumed abolton from 1 January199. Around each announcement date we consder event wndows wth dfferent start and end dates and varyng duratons. Budget speeches were delvered to Parlament n the afternoon on the dates n queston. We focus on an event wndow commencng at close of tradng the day before 11 The date from whch share transactons on the London Stock Exchange would be settled usng CREST. 1 Taurus was the ntended replacement for the Talsman settlements system. It was abandoned n March
13 the announcement. 13 It s not clear whether market partcpants would have had suffcent tme to react fully to the announcement on the day n queston. Allowng a longer tme perod for the market to react would ncrease the lkelhood of pckng up the full prce mpact of the stamp duty announcement n our data, but would at the same tme ncrease the rsk that we would also be pckng up the effects of extraneous tems of news completely unrelated to stamp duty. We consder event wndows stretchng from one to up to fve tradng days after the announcement. 4.3 Identfcaton of low- and hgh-turnover stocks atastream provdes daly data on the volume of shares traded after Bg Bang (October 1986) for stocks where, on average, 000 or more shares are traded daly. Snce three of the four events that we are consderng took place before or on the same date as Bg Bang, we are unable to use ths turnover data to group stocks by actual turnover n those cases. In our man results we therefore use market captalsaton as a predctor of turnover. To justfy ths methodology we examne the relatonshp between tradng volumes and market value durng the perod n whch we do have data. We defne a turnover rate as the fracton of outstandng shares traded n a year. Frst, we rank stocks where we have both market captalsaton and turnover data by market captalsaton n each year from 1991 onwards (the perod where the sample sze exceeds 500). 14 Fgure 1 plots the average annual turnover rates for four groups of stocks grouped by market captalsaton. 15 It shows that the average turnover rates of stocks n groups wth hgher market captalsaton s consstently hgher than that of groups wth lower market captalsaton. 13 It s possble that rumours may have leaked out pror to the announcement, but ther credblty would have been suspect. 14 For producng these charts we have dropped any frms that had less than 50 observatons per year or less than 4 years of data. Frms wth tradng ratos less than 1% per year are lkely to have unrelable prce date, because of an llqud market, and were also dropped. Fnally we dropped frms wth tradng ratos n excess of 00%, because of doubts over the relablty of ther data. 15 The fgure shows the unweghted average. A very smlar chart s obtaned f averages are weghted by market value, except that n the frst three years, the weghted average turnover rate of the top 100 frms s slghtly below that for the followng group (101 st to 50 th frm). A fracton of shares traded equal to 1 (or a tradng rato of 100%), ndcates that the annual number of transactons s equal to the number of shares outstandng. 1
14 Fracton of shares traded n year year Largest 100 frms 50th to 500th frm 100th to 50th frm Rest Mean turnover rates Fgure 1: Average turnover of stocks n dfferent sze classes n a gven year In order to avod problems of endogenety, we also show that rankng by market captalsaton n perod t-1 s a good predctor of a stock s rankng by share turnover n perod t. Table 3 shows that market captalsaton s a good predctor of turnover n the 1990 s, both for the current perod and for one perod ahead. Table 3: Rankng by sze n year t-1 as a predctor of rankng by turnover n year t-1 and t Market captalsaton at t-1 Average annual turnover at t-1 Average annual turnover at t top (.011).509 (.010) (.007).45 (.007) (.005).35 (.005) Rest.67 (.004).75 (.004) Notes: Robust standard errors gven n parentheses. An alternatve way to dentfy hgh-turnover stocks would be to use turnover data from the 1990s to allocate frms to groups and then to assume that turnover rates reman constant over tme. 13
15 Table 4 shows the correlaton between turnover rates (turnover / market value) at dfferent tme ntervals. We see that there s a hgh correlaton between adjacent perods, but ths correlaton becomes lower as we consder perods that are farther apart. Ths suggests that usng turnover data from later years may work for the 1990 announcement of the abolton of stamp duty, but t cannot be justfed for any of the earler changes. Table 4: Correlaton between stock turnovers at varous dates 16 t t-1 t- t-3 t-4 t-5 t-6 t-7 t 1.00 t t t t t t t Our preferred ndcator of turnover therefore s the average market captalsaton n the perod precedng the event, whch appears to be a good predctor of turnover n the current perod durng the 1990 s. Unfortunately we are unable to test whether the same s true for the 1980 s because the data are ether unavalable pror to 1991 or scarce. 17 Nevertheless, we proceed on the bass that the relatonshp between market captalsaton and turnover durng the 1980 s was smlar to that observed n the 1990 s. If ths were not the case, and sze were a less good predctor of turnover n the 1980 s, then f anythng our results would tend to be based aganst fndng a dfferental mpact of stamp duty cuts on the market value of hgh turnover stocks. Ths s because each sze groupng would contan a mxture of low- and hgh-turnover stocks, basng the estmated coeffcent on stocks classfed as hgh turnover towards zero. 16 Each correlaton was calculated from the same sample of 1531 observatons, therefore the coeffcents are comparable. 17 Some data are avalable from 1986 onwards, but for less than 500 companes, whch s not suffcent for our approach of groupng frms nto four sze bands. 14
16 5 Emprcal results Ths secton summarses the man results for each event referred to earler. We frst present the results usng sze as a proxy for turnover rates, as ths approach s possble for all the dates we consder. We then show, for the 1990 announcement, addtonal results usng the actual turnover data. 5.1 Results usng sze as a proxy Table 5 shows the results from regressng the cumulatve return from the day before to the day after the event on sze dummes. These dummes are defned as follows: The dummy labelled largest 500 s one for each frm that belongs to the largest 500 frms of the sample. A postve co-effcent thus ndcates that the largest 500 frms experenced hgher returns over the relevant perod than the smaller ones. The next dummy, largest 50, equals one, for frms that are among the 50 largest ones. The coeffcent thus tells us how much larger (or smaller) the returns of the 50 largest frms are compared to the group of the 500 largest. The remanng dummy largest 100 s defned smlarly. Table 6 shows the same regressons but for a cumulatve return over a longer tme nterval, from the day before the reform to fve days after. 15
17 Table 5: Results of regressons of two-day return (t-1 to t+1) on sze bands. ate of stamp duty change announcement / mplementaton ep var: Return 13 March 1984 (announcement and 18 March 1986 (announcement) 7 October 1986 (mplementaton 0 March 1990 (announcement) mplementaton) date) (1) () (3) (4) Largest (0.004) (0.004) (0.003) (0.00)** Largest (0.003) (0.003)** (0.00) (0.00)*** Largest (0.00)*** (0.00)*** (0.00)* (0.001) Constant (0.001)*** (0.001)*** (0.001)*** (0.001)*** Observatons R-squared F-statstc Robust standard errors n parentheses * sgnfcant at 10%; ** sgnfcant at 5%; *** sgnfcant at 1% Table 6: Results of regressons of one-week return (t-1 to t+5) on sze bands. ate of stamp duty change announcement / mplementaton ep var: Return 13 March 1984 (announcement and 18 March 1986 (announcement) 7 October 1986 (mplementaton 0 March 1990 (announcement) mplementaton) date) Largest (0.007)** (0.007) (0.008) (0.005)* Largest (0.005) (0.006) (0.007) (0.004)** Largest (0.003)*** (0.004)** (0.005) (0.00) Constant (0.00)*** (0.00)*** (0.00)*** (0.001)*** Observatons R-squared F statstc Robust standard errors n parentheses * sgnfcant at 10%; ** sgnfcant at 5%; *** sgnfcant at 1% The results are broadly as predcted by theory. We fnd that the shares of larger frms, whch are on average more frequently traded, earn hgher returns than those of smaller frms, at the tme that reductons are announced, though not on the mplementaton date of the 1986 rate cut. The precse pattern across sze bands s not always the same. ependng on the event and on the event wndow, dfferent sze dummes may have sgnfcantly postve coeffcents. Generally the 16
18 dfference between the largest 500 frms and the remanng frms tends to be more sgnfcant than dfferences wthn the group of the largest 500 frms, except n 1990 when the greatest effect was seen for the largest 50 frms. The general absence of dfferental prce mpacts around mplementaton date of the 1986 rate cut s reassurng, because, under the assumpton of effcent markets, the beneft of a lower stamp duty rate should have been prced n at the tme of announcement. The results for the 1990 announcement are also nterestng. We fnd a strong prce mpact n the expected drecton, suggestng that the market consdered the announcement of the abolton to be credble. 5. Results usng share turnover volume data As mentoned above, turnover volume data are generally avalable from 1991 onwards. For some frms, however, wth average turnover n excess of 000 shares per day, they become avalable from late 1986 onwards. It s therefore possble to use these data drectly to allocate frms nto turnover bands, at least for the 1990 event. The data are scarce though: we have suffcent volume nformaton for 166 frms only. These are all relatvely large frms. 96 of the 100 largest frms are ncluded n ths group and more than three quarters of these 166 frms are among the largest 150 frms. Gven the lmted number of observatons on volume data, we splt these frms nto only two groups at the medan turnover rate (defned as turnover dvded by market value) wthn ths sample. As well as comparng the returns of the most heavly traded frms to the remanng frms wth tradng volume data, we can also compare the return of all frms wth volume data to those wthout, because we know that only frms wth frequently traded shares wll have volume data for ths perod. The results of regressons of cumulatve returns over two days and one week are shown n columns (1) and () of Table 7. 17
19 Table 7: Results of regressons of cumulatve return on turnover band around March 1990 announcement. (1) () (3) (4) turnover rate > medan Cumulatve return Cumulatve return Cumulatve Cumulatve (t-1 to t+1) (t-1 to t+5) abnormal ret. abnormal ret. (t-1 to t+1) (t-1 to t+5) (0.003) (0.006) (0.003) (0.006) has turnover data (0.00)** (0.005)** (0.00)** (0.004)** Constant (0.001)*** (0.001)*** (0.001)*** (0.001)*** Observatons R-squared F-statstc Robust standard errors n parentheses * sgnfcant at 10%; ** sgnfcant at 5%; *** sgnfcant at 1% These results confrm that frms whose shares have hgher turnover rates benefted from relatvely hgher rates of return around the March 1990 announcement of the abolton of stamp duty. The dfference wthn the group of hghly traded frms wth volume data s small compared to the dfference between all hghly traded frms and the rest of the market. Another experment that we can do wth the volume data s to repeat the regresson usng abnormal returns rather than total returns as the dependent varable. Whle ths was not approprate when usng sze as the groupng varable (see Appendx), there s less reason why ths should be unnformatve when we use actual volume data. Indeed columns (3) and (4) reveal that the results wth abnormal returns are very smlar to the results usng total returns. 6 Summary and concluson In ths paper we have analysed the effect of changes n stamp duty rates on share prces. We fnd that stamp duty clearly depresses share prces, partcularly for frms wth more frequently traded shares. 18
20. 19
21 Appendx: Abnormal returns It s common n event studes to use ether a statstcal or economc model to control for changes n share prces that were caused by factors unrelated to the events studed (see MacKnlay, 1997). The most wdespread method s to focus on abnormal returns by calculatng for each share ts normal correlaton wth market movements ( beta ), and then focussng on any return n excess of that explaned by market movements. 18 The event studed n ths paper dffers fundamentally from the events analysed n most event studes, as t affects all shares (although to dfferent degrees) rather than just a few. Unlke n other event studes, the event tself wll thus have a consderable mpact on the market return. To see ths more clearly, consder the followng equaton, specfyng the relatonshp between the return on a share and the market return: r = R β r m where r s the abnormal return, R s the total return, r m s the market return and hstorcal correlaton between the market and ndvdual returns. β s the In an event study the am s usually to dentfy the effect caused by the event, rather than by other nformaton httng the market on the same day. In most studes ths s straghtforward, as the event wll have (vrtually) no effect on the market return. A merger announcement, for example, s unlkely to affect the market return, as long as the mergng frms are small relatve to the market. In these cases the mpact of the event on the return s smply the abnormal return. If however the event beng studed has a substantal mpact on the market return, and partcularly f the β vary systematcally wth the characterstcs of the dfferent groups of frms beng consdered, ths approach can gve a msleadng mpresson of the mpact of the event on the share prces of dfferent groups of frms. Ths concern n present n our context, as we llustrate below. 18 Although ths method s wdespread, t has not been used n emprcal studes of stamp dutes. These studes have ether focussed on total returns, or n the case of OXERA (001) on total returns n excess of the market return, but wthout allowng the mpact of the market return to dffer by frms,.e. assumng beta=1 for all frms. 0
22 The dfference-n-dfferences approach, whch restrcts ts attenton to relatve dfferences n return, makes the calculaton of abnormal return unnecessary as long as market betas are not systematcally dfferent across groups. So the dscusson above mght appear unnecessary. However, when we calculated betas and compared them to the sze dstrbuton, we found that they are clearly ncreasng n sze, as s demonstrated n Table 8. Table 8: Betas by frm sze 1990 Rank of frm Avg. beta S.e Notes: Betas calculated by regressng daly returns of ndvdual shares on the returns of the FT All Share ndex over the year pror to the 1990 event. The fndngs from Table 8 suggest that there s a fundamental dffculty: If betas are ncreasng n sze, and share turnover s too, then t s dffcult to dstngush between a postve aggregate shock to the stock market and a change to stamp duty, because both would cause dfferentally hgher returns for the shares of larger frms. Unfortunately usng abnormal returns does not provde a soluton to ths. Suppose there s an announcement of the abolton of stamp duty (as n 1990). Assume for smplcty that on ths day nothng else happens on stock markets and that the market return wll only be postve because of ths event. Table 9 shows the abnormal returns one would expect to see n that case. Table 9: Theoretcal abnormal returns (1990) Sze band Turnover rate Expected return MV share Market return beta Abnormal return Top % 74.1% 6.3% % % 15.3% 6.3% % % 6.4% 6.3% % rest % 4.% 6.3% % Turnover rates are ncreasng n sze, as documented n secton 4.3. The expected returns for each sze group are calculated as n Table 1, assumng a dvdend yeld of 4%. Usng the share of the market value made up by each sze group, the market return s obtaned. Clearly ths s manly drven by the effect on large frms. The betas are calculated for each sze group and are 1
23 ncreasng n sze. Applyng then the formula for the abnormal return, we fnd that the largest frms had the lowest abnormal return. Concludng from ths that they had not been affected by the stamp duty cut would be a mstake, as by assumpton the stamp duty cut was the only event occurrng. The problem s that the largest group prmarly drves the market return. At the same tme, wth a beta close to one, almost all of the effect s subsequently deducted. For practcal purposes ths means that f one s studyng an event wth mportant effects on market returns, focussng on dfferences across frms n abnormal returns may be msleadng. If betas dffer across groups, then ths wll even affect dfference-n-dfferences regressons. In the partcular case of dfferences by frm sze, snce betas are ncreasng n frm sze, the entre effect can be wped out f usng abnormal returns. In the opposte case of decreasng betas, the effect would be overstated. It may therefore be preferable to use total returns, partcularly f the market return over the perod s to a large extent drven by the event beng studed. Ths s the reason why ths paper has used total returns, as have all other papers n ths lterature, 19 though wthout provdng an explanaton. In prncple ths argument also holds for regressons usng actual tradng volume data to group frms. However, because the correlaton between sze and tradng volume s not perfect, t s possble that abnormal returns wll not be fully elmnated by the mechansm descrbed above. Indeed, n our regressons based on volume data, we fnd that ths s case (see secton 5.). References Atken, M. and Swan, P. (000), The mpact of a transacton tax on securty market traders: the case of Australa s tax reducton, Workng Paper, Unversty of Sydney Brealey, R. A. and S. C. Myers (000) Prncples of corporate fnance Sxth Edton, Irwn/McGraw-Hll. Ercsson, J. and Lndgren, R. (199), Transacton taxes and tradng volume on stock exchanges: an nternatonal comparson, Stockholm School of Economcs, epartment of Fnance, Workng Paper no. 39. Hau, H. and Chevaller, A. (000), Estmatng the volatlty effect of a securty transacton tax, ESSEC, Graduate Busness School, mmeo. 19 Except for OXERA (001) as mentoned above. Ths paper however assumes a fxed beta of 1, whch would only affect the constant n a dfference-n-dfferences regresson.
24 Hawkns, M. and J. McCrae (00) Stamp duty on share transactons: s there a case for change? Commentary 89, London: Insttute for Fscal Studes. Inland Revenue (00) Annual Report for the Year Endng 31 March 00, The Statonary Offce. Jackson, P. and O onnell, A. (1985), The effects of stamp duty on equty transactons and prces n the UK Stock Exchange, Bank of England, scusson Paper no. 5. Lndgren, R. and Westlund, A. (1990), How dd the transacton costs on the Stockholm Stock Exchange nfluence tradng volume and prce volatlty?, Skandnavska Ensklda Banken Quarterly Revew, /1990, pp MacKnlay, A. Crag (1997) Event Studes n Economcs and Fnance Journal of Economc Lterature, Vol pp OXERA (001) Impact of Stamp uty on the Cost of Captal of UK Lsted Companes paper prepared for the London Stock Exchange / The Hundred Group of Fnance rectors Saporta, V. and K. Kan (1997), The effects of stamp duty on the level and volatlty of UK equty prces, Bank of England, Workng Paper no. 71. Swan, P. L. and J. Westerholm, 001. The Impact of Transacton Costs on Turnover and Asset Prces; The Cases Of Sweden's and Fnland's Securty Transacton Tax Reductons, epartmental Workng Papers 144, Tor Vergata Unversty, CEIS Tobn, J. (1974) The new economcs one decade older Prnceton, NJ: Prnceton Unversty Press. Umlauf, S. (1993), Transacton taxes and the behavour of the Swedsh stock market, Journal of Fnancal Economcs, 33, pp
Do stock prices underreact to SEO announcements? Evidence from SEO Valuation
Do stock prces underreact to SEO announcements? Evdence from SEO Valuaton Amyatosh K. Purnanandam Bhaskaran Swamnathan * Frst Draft: December 2005 Comments Welcome * Purnanandam s an Assstant Professor
CHOLESTEROL REFERENCE METHOD LABORATORY NETWORK. Sample Stability Protocol
CHOLESTEROL REFERENCE METHOD LABORATORY NETWORK Sample Stablty Protocol Background The Cholesterol Reference Method Laboratory Network (CRMLN) developed certfcaton protocols for total cholesterol, HDL
Bank Credit Conditions and their Influence on Productivity Growth: Company-level Evidence
Bank Credt Condtons and ther Influence on Productvty Growth: Company-level Evdence Rebecca Rley*, Chara Rosazza Bondbene* and Garry Young** *Natonal Insttute of Economc and Socal Research & Centre Short-term and Long-term Market
A Presentaton on Market Effcences to Northfeld Informaton Servces Annual Conference he Short-term and Long-term Market Effcences en Post Offce Square Boston, MA 0209 Charles H. Wang,
CHAPTER 7 THE TWO-VARIABLE REGRESSION MODEL: HYPOTHESIS TESTING
CHAPTER 7 THE TWO-VARIABLE REGRESSION MODEL: HYPOTHESIS TESTING QUESTIONS 7.1. (a) In the regresson contet, the method of least squares estmates the regresson parameters n such a way that the sum of.,
Journal of Empirical Finance
Journal of Emprcal Fnance 16 (2009) 126 135 Contents lsts avalable at ScenceDrect Journal of Emprcal Fnance journal homepage: Costly trade, manageral myopa, and long-term. | http://docplayer.net/9530588-Stamp-duty-on-shares-and-its-effect-on-share-prices.html | CC-MAIN-2018-34 | refinedweb | 7,754 | 65.46 |
Opened 7 years ago
Closed 7 years ago
#25576 closed New feature (fixed)
HttpResponse can't be wrapped by io.TextIOWrapper; add required IOBase methods
Description
In Python3, the stdlib CSV writer [1] is expected to write to a text file, not a binary file. Observe writing to a bytes buffer:
import io import csv b = io.BytesIO() w = csv.writer(b) w.writerow(['a', 'b', 'c'])
Traceback (most recent call last): File "test.py", line 8, in <module> w.writerow(['a', 'b', 'c']) TypeError: 'str' does not support the buffer interface
To handle this, one should use the stdlib's
io.TextIOWrapper [2]:
import io import csv b = io.BytesIO() wrapper = io.TextIOWrapper(b, 'utf-8', newline='') w = csv.writer(wrapper) w.writerow(['a', 'b', 'c']) wrapper.flush() print(b.getvalue())
b'a,b,c\r\n'
As Django's HttpResponse uses a binary file-like interface, I'd expect the same to work. That is, wrap the response in a
io.TextIOWrapper and write the CSV document to the wrapper. However, this fails:
import io import csv from django.http.response import HttpResponse r = HttpResponse() wrapper = io.TextIOWrapper(r, 'utf-8', newline='') w = csv.writer(wrapper) w.writerow(['a', 'b', 'c']) wrapper.flush() print(r)
Traceback (most recent call last): File "/home/jon/test.py", line 8, in <module> wrapper = io.TextIOWrapper(r, 'utf-8') AttributeError: 'HttpResponse' object has no attribute 'readable'
As HttpResponse is a binary file-like interface, I'm suggesting the necessary methods/members be added so that it can be wrapped by
io.TextIOWrapper. These methods/members are documented in io.BaseIO() [3]. From initial testing, only
readable() and
seekable() are required for my use case.
This will make it easier to integrate text-only file interfaces to the binary nature of the response.
[1]
[2]
[3]
+1 (in the same spirit as #18523). | https://code.djangoproject.com/ticket/25576 | CC-MAIN-2022-27 | refinedweb | 310 | 61.12 |
Ruby: Productive Programming Language
Every, Dave Thomas and Andy Hunt. The book also has an on-line version..
Dynamic language
A dynamic, productive, open source programming language with a focus on simplicity and productivity. It has an elegant syntax that is natural to read and easy to write.
ruby productivity measured
I made another kind of comparison.
I have implemented the "payroll" application from "Agile Software Development" in ruby. It took me 10 times less LOC than the author wrote it. Great isn' it.
Here is my post about it:
I think the names make a difference
Ruby sounds friendlier and more valuable than Python, and less icky than a collection of oyster spit... if it was called Diamond, it would be popular with the girls (and my wife would like it 'coz diamonds are worth 3 points and rubies only 1 in Rocks'n'Diamonds).
Yeah, -99, Totally Frivolous, I know.
The ruby book I'd like to see
I'd like to see a ruby book that covers the design aspects of OO programming, like 'the decorator pattern', 'the flyweight pattern', etc. I think ruby would be an excellent candidate for teaching this patterns to those interested in gaining OOP expertise.
Re: I'd like to see design patterns in Ruby....
You can... right here:
Great first language
Ruby also makes a great first language for those just starting to learn programming. The syntax is clean and simple and Ruby's underlying architecture is very consistent. You'll also learn a lot about OOP in the process.
Re: Ruby: Productive Programming Language
Maybe I am worse than other developers, but I find I often have to execute an edit/compile cycle because of an end-of-line typo.A text editor with syntax highlighting would probably fix that one for you.
Probably not
I think he's talking about forgetting the end of line semicolon ';' that is required in most languages (In Ruby they are optional). Syntax highlighting won't help you catch that one.
Re: Probably not
Autoindenting (as in suitable emacs modes) catches
it very nicely -- you can see the next line doesn't indent
correctly if you're missing a ';'.
Re: Probably not
Yeesh! We've already got a Ruby vs. Python religious war going on here. Let's not bring Emacs into it!
Emacs autoindenting probably does catch 90% of my syntax mistakes, though. And it works with Ruby. ;)
bah Emacs! VI would catch
bah Emacs! VI would catch it twice as fast, correct it for you and give you a tip on how to write the rest of the program!
Re: Ruby: Productive Programming Language
I'm a perl hacker turned python programmer who is occassionally tempted by new languages. Ruby has tempted me a few times for different reasons: the main one just due to the very visible large amount of activity around the language (the rapid proliferation of modules and whatnot). However I've never gotten in to Ruby, and each time i'm tempted by it the temptation is shorter lived. I always come away feeling just the opposite of this article's author: that Ruby is a sort of bastard child of python, perl and java combined, taking good elements of each, but when combined they make for a horrific mix. Perhaps this is just me. Obviously the author of this article sees things just the opposite. And different people will see things different ways. Some people even still really like perl, after all!
However, everyone should note the corrections to the author's statements about various languages, especially Python. It shows that while he has his own valid experiences, he certainly doesn't know Python as well as he lets on he does.
Bastard child of ?
I read your "bastard child" comment with great amusement.
I began programming in assembler on IBM System/360s in the mid 1960s & have worked with most major languages since (even did a stint as a compiler trouble shooter for Cobol & Pl/1 on mainframes). Have done Basic-many variants, Cobol-many many variants, got into 'C' and Unix shell scripting early (1981) and worked with most shell environments from the early Unix V7 & Xenix 1.0 days up to AIX 5.3 & ksh. Did extensive work using awk & sed. Also did some Perl. In particular got into Smalltalk & Java at roughly the same time - late 1994 for Smalltalk & early 1996 for Java. I, 1997 was invited to be a presenter on the 1st Java world tour (the Asia leg).
Just recently (2004) I spent a year rewriting somone's earlier async order taking servers, written using an async package & IBM's REXX on OS/2, so we could get them onto Windows. So I have no qualms about switching languages on the basis that I will use whatever is needed to get the job done. Each language has its strengths.
One language I avoided was C++, In 1994 I made a choice to go Smalltalk after realising that to program succesfully in Smalltalk would mean I got dragged screaming & kicking into pure OOT whereas it was equally clear to me that C++ would allow anyone to write almost anything & call it whatever they liked, including in so many cases, OOT when it wasn't.
I still develop in Smalltalk and Java. As time passed I got to like Java less and Smalltalk more but the world had voted in terms of popularity & Smalltalk is on a slide out of the way.
Then I found Ruby and RubyOnRails.
Rather than feel it was the 'bastard child' of some of the other languages that I liked, I concluded (as I am sure all intelligent insightfull developers who are freed from emotional bonds to favoured habits, will) that Ruby truly is a extraordinarity elegant integration of the best of all that I liked.
Your 'bastard child' remark appears to me to say more about yourself and your perceptions that it does about Ruby.
I haven't been so excited about a new language and its supporting environment, since Java exploded on the programming scene.
Cheers
Doug Marker
Re: Ruby: Productive Programming Language
SUMMARY:
- There is no *evidence* that Ruby's design is "friendly" whereas there is for Python.
- Evolutionary processes can and do create elegant designs.
DETAIL:
I would and do pick Python for one simple reason:
It was designed to be user friendly, easily readable, etc.
Ruby was not.
Python came from languages where readablity was actually studied. [Note: If you can read dutch or want to send away for the study you can.]
Ruby syntax is supposed to be an improvement on some other language's syntax: Well prove to me that it is an improvment! [Note: There is none. Did Matz sit 1 000 programmers down with different syntaxes to determine which was was more "intuitive"? No.]
Every statement like "@ and @@ are simple indicators that once learned help a lot" -- are meaningless. This statement is backed-up by nothing! We are supposedly Computer SCIENTISTS -- where is the science in Ruby's design?
In short, a language designer ought to also be cognitive scientists, linguists, etc. AFAIK, neither Matz or Guido are -- but at least Guido made the EFFORT to study readability! And for this effort, I use Python.
Can I learn Perl's special vars? Yes. Can I learn Ruby's member scoping rules? Yes. But just because I can memorize rules does not mean the usability is high.
As for tacking on OO -- even if so what is wrong with doing so? I believe evolution creates elegant designs; and unless Ruby is either perfect or will never change SOMETHING will be "tacked on" and will you call it bad?
Computer Scientists != User Interface Designers
Yes, we all know how evolution leads to elegant architectures. Take Perl for instance - oh wait, nevermind ;-).
Actually, you are right - to a point. In fact, Grady Booch in "Object Oriented Analysis and Design" expressly states that a successful system cannot be gotten right the first time, but must be built incrementally and iteratively, an evolutionary process. However, he also makes it unambigously clear that there is one property that a system *must* have at the beginning for a successful evolution to occur: "The existence of a strong architectural vision". Ruby is based on a simple, strong architectural vision - the proven, Smalltalk-like pure object-oriented language. Python is based on several competing, vague visions - first a procedural scripting language, then an object-oriented language, then a functional language. Each one added piecemeal, degrading the architectural purity of the system.
Computer scientists, in general, are not overly concerned with "friendliness". BASIC, and VB, were designed to be "friendly" - but they are almost unversally denounced by programmers as awful programming languages. From a CS perspective, a language stands or falls based on the soundness, elegance, and completeness of it's basic architecture. Python's architecture is a congealed mess of ideas, whereas Ruby is based on an extremely sound, elegant, and complete Smalltalk-like architecture. However, even if you believe that "friendliness" is more important than elegance, consider the "self" declarations in Python methods. They are an eyesore, a burden to the beginning student of OOD, a gaping hole in Python's "friendliness". And their sole reason for existance? A crutch for the compiler because of the half-assed way OO is tacked-on. This is why a sound architecture is necessary for the start, even if your goal is "friendliness" rather than consistency. A vague initial vision will effect every aspect of the resulting system. Consider also the confusing mixed-messages the beginning Python student recieves when reading other's code - strings manipulated either with the string module or the built-in methods, depending on when the code was written. User classes descended either from UserList( or whatever it's called) or List depending on whether the code was written pre- or post- Python 2.2. Code that hacks around Python's former lack of real scoping, or code that doesn't - depending on the era in which it was written. The beginning student cannot get a clear picture of proper Python style because the language is such a moving target even many years after it's inception.
Strangely though, despite Guido's user-studies, I find Ruby code to be almost invariably easier to read than Python. Names are better-chosen, control structures are more readable (e.g. "9.times do ... end" instead of "for i in range(0,9): ...", and in general Ruby is terse without losing readability (and no, there is never any reason to use the perlish line-noise variables like $_ if you don't want to). Also, while this is hardly conclusive, I once sat my wife ( a non-programmer) down in front of a simple loop coded in various languages including idiomatic Ruby and Python. She immediately identified the Ruby example as being the most readable, including correctly identifying what it did. There's just something inherently more readable about the Ruby "collection.each do ... end" set of idioms than the Python "for x in y:" syntax. But of course, that's opinion.
Re: Computer Scientists != User Interface Designers
You know quoting is not as convenient here as on Usenet. If you don't write reasonably short paragraphs, don't expect useful followups to you posts.
Re: Computer Scientists != User Interface Designers
If language designers are not "user interface designers" then we should stop all the baseless, irrational discussion of which is more readable. Only until such things are taken seriously with real science behind them will the discussion be fruitful.
Until then, Python is the only scripting language I know that made any effort along these lines -- and ought to be recognized for it and not dismissed with 'well, I like ____ better' (which is not appropriate from computer "scientists" or any rational being).
In response to one particular part of your/this comment; are not the following basically the same:
self.length = length
self.width = width
self.area = length * width
and
@length = length
@width = width
@area = length * width
How is this any different? How is 'self' (or as I am sure you know, 'self' may be 'this', or 'me', or 'instance', or 'this_here_object', or '_') worse than '@'??
Re: Computer Scientists != User Interface Designers
"In response to one particular part of your/this comment; are not the following basically the same:
self.length = length
self.width = width
self.area = length * width
and
@length = length
@width = width
@area = length * width"
Not at all, because you're leaving out part of the picture: In Python for every method on a class you've got to declare 'self' as the first argument, like:
class Rectangle:
#assuming length and width were set in the
#constructor, which I didn't define here for brevity
#and because I'm forgetting Python ;-) :
def area(self)
return self.length * self.width
#or: return self.area if it was calculated in the c'tor
What's with that 'self' you have to pass into the area method? But when you use it, you don't pass in 'self':
x = rectangle.area()
In Ruby it would be like this:
class Rectangle
def initialize(length, width) #constructor
@length = length
@width = width
@area = length * width
end
def area #actually, you could use attr_reader
return @area
end
end
#use it:
r = Rectangle.new(5,4)
x = r.area
To summarize:
* In Python 'self' is implicitly passed as the first parameter for a class' method. This is so the method gets a reference to the object it's in, otherwise it would have no idea which object it was being called on.
* In Ruby '@' indicates that the scope of a variable is within the current class (a class variable). Ruby methods 'know' whic object they were invoked on.
As far as 'readability' goes: It's subjective and in the eye of the beholder. After you learn a language it tends to be readable to you (except for perhaps Perl :)
Re: Computer Scientists != User Interface Designers
self must be explicitely declared before it can be used. 'self.' is 4 characters longer than @. Python lacks true lexical variables. Python lacks real closures (man, don't I wish it has a real lambda?).
I think Python's greatest advantage is that while it's a 'middle-of-the-way' language, meaning of mediocre design, it is much better designed than perl and infinitely more readable than perl... And, it while it is much worse than Ruby in its design, readability and expressiveness, it enjoys (unfortunately, because Ruby is better, and fortunately because perl is worse) a rather large following and is mature enough to used in the enterprise. So, if you had to pick a scripting language out of the enterprise-ready languages, Python would take the cake. But it definitely doesn't take any cakes for its design, save using indent level for deliniating code blocks, which I think is a win, because it means that all Python code is guaranteed to be indented properly. I wish Guido would understand that such fascist enforcement of a guarantee is just as needed for variables: Python needs true lexical (or more accurately, private) variables. It's really hypocritical of Guido to say that convention offers enough protection for variables, but yet, convention doesn't offer enough protection for indent levels. That's just a bunch of...
Ruby is the future once it matures to the point of Python. What pains me the most about Ruby is nothing theoretical, but rather the pragmatic lack of decently old and stable modules. Man, Ruby takes the cake for having the most 0.0.0.0.1 version modules! That definitely sucks and limits its adoption to but a few visionary pioneers.
Re: Ruby: Productive Programming Language
I'm a C++ hacker and general language hobbyist who learned Ruby and Python concurrently. It is quite incorrect to say that Ruby is a child of either Python or Java. When Matz set out to create Ruby, one of his stated goals was to create something different from Python, which he didn't particularly like. I'd say he succeeded, because Ruby shares almost nothing in common with Python except some similar syntax and the fact that they are both dynamically-typed, garbage-collected languages. It would be far more accurate to say that Ruby is Smalltalk with Perl syntax and an influence of Dylan, Sather, Lisp, and others. With it's metaclasses, true closures, and pervasive use of iterators and generators, coding in Ruby is very distinct experience from coding in Python. There is no Python influence except inasmuch as both Guido and Matz were influenced by some of the same predecessor languages.
As for the author's Python experience, he is quite correct in what he said. Python's OO was tacked-on, which Guido has never made any attempt to deny, although he doesn't widely publicise the fact either. Read through the Python FAQ sometime. The reason for the need for explicit declaration of the "self" argument in methods, as well as the longstanding separation of types and classes, are direct results of Python's procedural roots.
Re: Ruby: Productive Programming Language
I wonder if you had not gone from Perl -> Python if you would still feel this way about Ruby. In my experience it's a lot easier for Perl programmers to grok Ruby than to grok Python. Perhaps once one does grok Python it's difficult to grok Ruby (well, that can't be true because I've run into several Pythonistas who like Ruby).
Anyway, I'm not sure what you mean by a 'horrific mix', can you provide examples which illustrate this? In general I find that Ruby's features 'hang together' a lot better than Perl's or Python's, but this is subjective of course.
(and to be accurate, I don't think Matz borrowed anything from Java - he did borrow from Perl, Lisp, SmallTalk and Eiffel among others, but Java didn't exist yet at least not publicly).
Re: Ruby: Productive Programming Language
Perl does indeed support closures. I use them almost daily. I agree that a mastery of the language take a long time but that's part of it's appeal. Perl is probably the most expressive language out there. If you want to code Lisp-ish, you can, If you want to code like a C programmer, you can. If you want to hack a dirty script out or a rigorous OO system, TMTOWTDI.
OO Perl is not fun
From one who has done it more than once: OO Perl is ugly. Though I do agree with the author of the article: Doing OO Perl taught me a lot about OO inards because you have to do a lot of things yourself. That said, I really don't want to do OO Perl anymore when Ruby is so much nicer and allows me to be so much more productive.
Ruby also supports multiple styles of programming: OO, functional, procedural.
Ruby OOP vs Python OOP
One big difference between the two is that Ruby supports single inheritance versus Python's multiple inheritance. This design choice was for simplicity's sake since multiple parents can get confusing when inheriting methods from a net of ancestors.
In my opinion, I slightly prefer Python's OO capabilities over Ruby's. Particularly as the latest release Python (2.2) has some new features[1] which greatly enhance the usability of multiple inheritance. That said, I do agree that, in Ruby, everything feels more like an object (eg 0.upto(7) ).
[1] the two specific features I had in mind were cooperative methods using the super() function and a much better method resolution algorithm.
Guido himself doubted MI's usefulness
Here's an interesting usenet posting by Guido van Rossum (answering Bjarne Stroustrup, no less) in which he questions the usefulness of MI and is concerned about the overhead imposed by MI:
bs@alice.att.com (Bjarne Stroustrup) writes:
>MI in C++ and elsewhere isn't perfect and it isn't a panacea, but it works
>and it makes some styles of programming noticeably more convenient and
>less obscure. Naturally, it can also be overused and misused, but basically
>it works.
Point taken. However, I still worry about MI. When MI is *not* used,
it still imposes an overhead -- there is a "delta" offset in the vtbl
that is added to "this" each time a virtual function is called, but
this delta can only ever be nonzero when MI is used. I feel that this
is in direct conflict with the C++ philosophy that language features
you don't use shouldn't cause overhead.
I am also still looking for examples of the styles of programming that
are aided by MI -- anyone got pointers?
--Guido van Rossum, CWI, Amsterdam
"You can't do that in horizontal mode."
Re: Guido himself doubted MI's usefulness
If you read the entire thread, you'll see that Guido is wrong. MI doesn't need to cost anything if you don't use it.
Re: Ruby OOP vs Python OOP
"One big difference between the two is that Ruby supports single inheritance versus Python's multiple inheritance"
True. ( Personally, I tend to avoid using multiple inheritance even in langauges that allow it.) Ruby does have mixins, however. It means that you can define modules of methods that can be 'mixed-in' to classes in Ruby (mixing in functionality to a class). You can mix-in multiple modules to a class. While not the same as multiple inheritance, mixins can often be used as a replacement.
I've been using Ruby for well over a year now and I must say that I've never thought: "Oh, darn! I wish Ruby had multiple inheritance, I could really use it here!". Haven't missed it, but as I said above, I generally tend to avoid it anyway.
Given the choice of:
1) multiple inheritance, but no closures (Python)
2) single inheritance (with mixins) and closures (Ruby)
I'd pick #2 any day. ;-)
Wrong guesses about Python tho
Python, like Ruby and unlike Perl, is object-oriented in the core language and all major libraries. But Python doesn't force the programmer to use OOP notation when it isn't helpful. The claim that OOP support was an afterthought in Python is incorrect.
In practice, using indentation to control block scope is a big win in code readability in spite of occasional problems with busybody text formatters and skeptical programmers. Similarly, the other statements about Python don't match my experience. Since I've looked at Ruby about as much as the author seems to have looked at Python, I'll refrain from evaluating Ruby."
Please quote the FAQ. Otherwise, this is just FUD.
At least, the answer to the question "* 6.7. Why must 'self' be declared and used explicitly in method definitions and calls?" doesn't allow saying what you assert.
Moreover, if, as you said it, "OO /was/ tacked on as an afterthought" in Python, this would not be a valid argument: does this looks familiar to you:
"Hello everybody out there using minix -
I'm doing a (free) operating system (just a hobby, won't be big and professional like gnu)"
(hint:...)
Are you suggesting Linux is not big, or not professional?
Re: Wrong guesses about Python tho
"Python, like Ruby and unlike Perl, is object-oriented in the core language and all major libraries. "
However,.
On the otherhand, Ruby has had a unified type/object system and iterators from the start, so Ruby's libraries were written with these in mind. This is especially important when it comes to iterators. So while Python users will claim that Python now has iterators (and it does) it's built-in libs do not take advantage of them (at least not yet).
It must also be noted that Python doesn't have closures. While closures may seem to be an obscure feature (and they are not specifically an OO feature), once you figure out what they're good for and come to appreciate their power (it took me a while:) they can end up saving you a lot
programming time in certain applications.
"But Python doesn't force the programmer to use OOP notation when it isn't helpful."
Ruby doesn't force it either. You can define standalone methods, however, they become methods in the Object class, but you can use them in a non-OO way if you like.
"The claim that OOP support was an afterthought in Python is incorrect. "
If that is the case, then why does 'self' have to be the first parameter for all instance methods in a Python class? (and when you actually call the method you have to pretend to not use the first argument )
Python's use of indentation as a syntactical element is more of an issue of personal preference. Some people really like it and others really don't.
Re: Wrong guesses about Python tho
."
Well, Python's standard library is rich and runs perfectly well, so I don't see the problem.
"It must also be noted that Python doesn't have closures."
What about this:
(you know about Google, don't you?)
"If that is the case, then why does 'self' have to be the first parameter for all instance methods in a Python class?"
Well, because it *is* an argument. A method is a function related to a class. When called, it has to know to which instance of the class it is to be applied.
"(and when you actually call the method you have to pretend to not use the first argument )"
This is wrong. When you write (sorry for the indentation):
class MyClass:
def foo(self, arg1):
print "Hey! I am no %s!" % arg1
instance = MyClass()
instance.foo("bar")
you give foo a real information by prefixing it by "instance.". You said it: an argument.
In fact, you really can supply "instance" as the first argument of foo in the "normal" way for functions:
MyClass.foo(instance, "bar")
This just means : get the function which is MyClass foo method and call it with instance and "bar" as arguments.
For more clarity (interactive Python prompt):
>>> MyClass.foo
MyClass.foo is an unbound method: it is a function related to a class, but is not bound to any instance of MyClass. You call it with the instance as the first argument:
>>> MyClass.foo(instance, "bar")
Hey! I am no bar!
or, similarly:
>>> f = MyClass.foo
>>> f(instance, "bar")
Hey! I am no bar!
On the other hand, instance.foo 1) is the foo method of MyClass and 2) is bound to the instance of this class referenced by the variable "instance":
>>> instance.foo
There is therefore no need to tell it to which instance it has to apply:
>>> instance.foo("bar")
Hey! I am no bar!
or, similarly:
>>> g = instance.foo
>>> g("bar")
Hey! I am no bar!
This is easy, isn't it? At least, it should be, for visionary people using Ruby. Or did you just move from Perl to Ruby because they look about the same? ;-)
Re: Ruby: Productive Programming Language
Being something of a Python fan, I just thought I'd clear something up...
"It gives a lot but runs short, for example, with object elements all being public."
Actually, you can make members private in python... any identifiers that start with two underscores (ie, __myvar) are private.
Personally, I don't see what Ruby has to offer that Python doesn't, and I find Python syntax much more readable. But, to each his own.
Re: Ruby: Productive Programming Language
this isnt actually true, if you use __myvar in python it becomes munged internally to __Class_myvar (or something similar, i forget), but is still accessible outside the class. this is the type of dirty hack that you dont find in ruby.
Re: Ruby: Productive Programming Language
Unless you are more accurate, this is just FUD as this interactive session demonstrates (sorry for the indentation, which is not preserved AFAIK by this web site's engine):
>>> class A:
... pass
...
>>> a = A()
>>> a.>> __A_myvar
Traceback (most recent call last):
File "", line 1, in ?
NameError: name '__A_myvar' is not defined
>>>
Re: Ruby: Productive Programming Language
Fundamentally, no language has any more to offer than any other. As long as the language is turing-complete, it's functionally equivalent to all others. Ruby, however, is avery, very different animal from Python. The difference is far more than syntax - the architecture is altogether different. I learned Ruby and Python together, and as a working programmer, I find Ruby to be a vastloy more productive, pragmatic, elegant, and reable language than Python. But, as you say, to each his own.
Look for Ruby to grow
I like the comment that another poster submitted:
"Ruby is Perl's younger, prettier sister."
But Ruby is growing to maturity. As a Perl refugee myself, I believe that Ruby will begin to (or I should say: continue to) attract a lot of Perl Programmers. I'm not sure about Python users, but the Perl userbase is much larger anyway. Python and Ruby tend to play in the same space: Object Oriented Scripting languages - though many would argue that Ruby (and especially the way Ruby's libraries are set up) has a much more Object Oriented 'feel'. Perl users who try Python tend to not take to it too naturally, but in my experience, Ruby is a very natural progression from Perl.
Some Perlists will complain that Ruby's RAA is not as complete as Perl's CPAN, but there is a lot of work being done to remedy that situation. And in some cases Ruby comes 'out-of-the-box' with some things that Perl doesn't have (unless you download them from CPAN), for example: In Ruby if you have two arrays and you want their difference:
array1 = ['a','b','c','d','e']
array2 = ['c',d']
array3 = array1 - array2
#array3 is: ['a','b','e']
Anyway, I predict that Ruby will eat into Perl's userbase and the erosion will be significant and noticeable by this time next year.
Re: Look for Ruby to grow
The Pike language has had this feature for a long time.
As well as (e.g.):
array a = ({1,2,3}) | ({2,3,4});
// a is ({1,2,3,4})
array b = "Pike programming language" / " ";
// b is ({ "Pike", "programming", "language" })
and many other small conveniences.
It is also an OO interpreted language, and has excellent performance.
Re: Look for Ruby to grow
"The Pike language has had this feature for a long time. As well as (e.g.):
array a = ({1,2,3}) | ({2,3,4});
// a is ({1,2,3,4})"
Well, of course you can also do this in Ruby:
a = [1,2,3] + [2,3,4]
# a is [1,2,3,4]
"It [Pike] is also an OO interpreted language, and has excellent performance."
Looks like Pike is statically typed. Ruby is dynamically typed like Python or SmallTalk. Doing OO programming in a dynamically typed language 'feels' a lot different than doing OO in a statically typed one. I prefer the freedom of dynamically typed languages - it seems like I can get a lot more done with less code and in less time.
-prog_man
Re: Look for Ruby to grow
> Well, of course you can also do this in Ruby:
OK, of course I'm not surprised.
In Pike, however, a+b is a different operation
from a|b (assuming a and b are arrays):
array a = ({1,2,3})
array b = ({2,3,4})
// a|b is ({1,2,3,4})
// a+b is ({1,2,3,2,3,4})
> Looks like Pike is statically typed.
Not really. Pike's type system is quite flexible, you can
usually constrain a variable's type as much (or as little)
as you like, so that run-time errors or warnings may be
generated when the actual value doesn't make sense.
E.g. the following are valid variable declarations in Pike:
int(0..10) k;
string|array(string) foo;
int|float bar;
function(int:string) fun;
mixed whatever;
with `mixed' meaning the variable is allowed to have any
type at all.
Re: Look for Ruby to grow
>OK, of course I'm not surprised.
>In Pike, however, a+b is a different operation
>from a|b (assuming a and b are arrays):
Ok to use + ou | in Ruby. And *, & and a lot of
methods.
Full reference in
Using Python libraries in Ruby?
"It is also quite straightforward to link up Ruby and Python libraries"
How does one go about doing this? I've been following Ruby for several months now, but I've never seen this mentioned before.
???
Re: Using Python libraries in Ruby?
A few seconds of perusing Ruby's website (the Ruby Application Archive, in particular) reveals:
-----
Ruby/Python is a Ruby extension library to embed Python interpreter in Ruby. With this library, you can use the libraries written for Python in your Ruby scripts. The most powerful feature of Ruby/Python is its transparency.
-----
I've never used it, but you can read more at:
But it only works with Python-1.5
Seems someone should look into updating this lib.
Re: Ruby: Productive Programming Language
The things that have turned me off from Ruby every time I've
looked at it have been
- Lots of inline regex a la perl
- Many strange operator symbols.
Your examples don't show any of this. Is the heavy
punctuation and inline regex something that is specific
to perl converts, or is it intrinsic to the language?
- jrodman
Re: Ruby: Productive Programming Language
The inline regex syntax is convenient to save keystrokes when coding, which is probably why it was carried over from Perl. But in Ruby it would be more "intrinsic" to do regex manipulation using the nice clean methods of the Regexp class. In my experience, the fact that Python lacked Ruby's built-in regex syntax often made it considerably less convenient for simple text processing.
Re: Ruby: Productive Programming Language
It seems funny to me that anyone would consider "inline regex"s a turnoff. When going from Python to Ruby that was one of the things I liked! Of course, in Python you don't want inline regexes because they would be recompiled every time they are used. In Ruby (ane Perl), the compiler is aware of regex syntax so can precompile the regex. I prefer to see simple regexes inline rather than having to leave the current context to find its definition somewhere else.
As to strange operator symbols -- well, strange is a function of familiarity. I agree, Ruby could have done without inheriting those special globals from Perl ($_, $&, etc.), but Python has its own wierd stuff too -- these couple come to mind:
Looping over lines of a file:
Python:
for x in file.xreadlines(): # this is the recently improved way replacing the old, 4-lines-of-code way!
Ruby:
while line = file.readline
Loop over integers from 1 through 10:
Python:
for i in xrange(1, 11):
Ruby:
for i in 1..10
Those Python constructs might look normal to someone who is familiar with Python, but for anyone else I'll bet the Ruby way is more intuitive.
Both Python and Ruby are excellent languages. Having used both extensively, I personally somewhat prefer the way Ruby does things.
Re: Ruby: Productive Programming Language
Your loop example is wrong.
In Python < 2.2, you can write:
for line in file.readlines():
(you don't *need* xreadlines)
and in Python 2.2 and above, as files support the iterator protocol, you can simply write:
for line in file:
The whole article above is real crap that shows only one fact: the author knows nothing about Python (and by the way discredits the Ruby community). Too bad.
I made a point-by-point reply to this article in French to the friend who pointed me to it. I'll translate it if someone here proves to be worth it (and asks me).
Re: Ruby: Productive Programming Language
Florent,
Python 2.2 was released on December 21, 2001 and the author claims to have switched to Ruby in March 2001. Please do the math.
Stephan
Re: Ruby: Productive Programming Language
Actually your Ruby examples are still a bit verbose :
Looping over lines of a file:
file.each { |line| ... }
Loop over integers from 1 through 10:
(1..10).each { ... }
__
Guillaume. | http://www.linuxjournal.com/article/5915?quicktabs_1=2 | CC-MAIN-2014-10 | refinedweb | 6,109 | 63.29 |
parsita 1.1.1
Parser combinator library for Python.
The executable grammar of parsers combinators made available in the executable pseudocode of Python.
Motivation
Parsita is a parser combinator library written in Python. Parser combinators provide an easy way to define a grammar using code so that the grammar itself effectively parses the source. They are not the fastest to parse, but they are the easiest to write. The science of parser combinators is best left to others, so I will demonstrate only the syntax of Parsita.
Like all good parser combinator libraries, this one abuses operators to provide a clean grammar-like syntax. The __or__ method is defined so that | tests between two alternatives. The __and__ method is defined so that & tests two parsers in sequence. Other operators are used as well.
In a technique that I think is new to Python, Parsita uses metaclass magic to allow for forward declarations of values. This is important for parser combinators because grammars are often recursive or mutually recursive, means that some components must be used in the definition of others before they themselves are defined.
Motivating example
Below is a complete parser of JSON. It could have be shorter if I chose to cheat with Python’s eval, but I wanted to show the full power of Parsita:
from parsita import * json_whitespace = r'[ \t\n\r]*' class JsonStringParsers(TextParsers, whitespace=None): quote = lit(r'\"') > (lambda _: '"') reverse_solidus = lit(r'\\') > (lambda _: '\\') solidus = lit(r'\/') > (lambda _: '/') backspace = lit(r'\b') > (lambda _: '\b') form_feed = lit(r'\f') > (lambda _: '\f') line_feed = lit(r'\n') > (lambda _: '\n') carriage_return = lit(r'\r') > (lambda _: '\r') tab = lit(r'\t') > (lambda _: '\t') uni = reg(r'\\u([0-9a-fA-F]{4})') > (lambda x: chr(int(x.group(1), 16))) escaped = (quote | reverse_solidus | solidus | backspace | form_feed | line_feed | carriage_return | tab | uni) unescaped = reg(r'[\u0020-\u0021\u0023-\u005B\u005D-\U0010FFFF]+')> rep(escaped | unescaped) << '"' > ''.join class JsonParsers(TextParsers, whitespace=json_whitespace): number = reg(r'-?(0|[1-9][0-9]*)(\.[0-9]+)?([eE][-+]?[0-9]+)?') > float false = lit('false') > (lambda _: False) true = lit('true') > (lambda _: True) null = lit('null') > (lambda _: None) string = reg(json_whitespace) >> JsonStringParsers.string> repsep(value, ',') << ']' entry = string << ':' & value> repsep(entry, ',') << '}' > dict value = number | false | true | null | string | array | obj if __name__ == '__main__': strings = [ '"name"', '-12.40e2', '[false, true, null]', '{"__class__" : "Point", "x" : 2.3, "y" : -1.6}', '{"__class__" : "Rectangle", "location" : {"x":-1.3,"y":-4.5}, "height" : 2.0, "width" : 4.0}' ] for string in strings: print('source: {}\nvalue: {}'.format(string, JsonParsers.value.parse(string)))
Tutorial
The recommended means of installation is with pip from PyPI.
pip install parsita
There is a lot of generic parsing machinery under the hood. Parser combinators have a rich science behind them. If you know all about that and want to do advanced parsing, by all means pop open the source hood and install some nitro. However, most users will want the basic interface, which is described below.
from parsita import *
Metaclass magic
GeneralParsers and TextParsers are two classes that are imported that are just wrappers around a couple of metaclasses. They are not meant to be instantiated. They are meant to be inherited from and their class bodies used to define a grammar. I am going to call these classes “contexts” to reflect their intended usage.
class MyParsers(TextParsers): ...
If you are parsing strings (and you almost certainly are), use TextParser not the other one. If you know what it means to parse things other than strings, you probably don’t need this tutorial anyway. The TextParser ignores whitespace. By default it considers r"\s*" to be whitespace, but this can be configured using the whitespace keyword. Use None to disable whitespace skipping.
class MyParsers(TextParsers, whitespace=r'[ \t]*'): # In here, only space and tab are considered whitespace. # This can be useful for grammars sensitive to newlines. ...
lit(*literals): literal parser
This is the simplest parser. It matches the exact string provided and returns the string as its value. If multiple arguments are provided, it tries each one in succession, returning the first one it finds.
class HelloParsers(TextParsers): hello = lit('Hello World!') assert HelloParsers.hello.parse('Hello World!') == Success('Hello World!') assert HelloParsers.hello.parse('Goodbye') == Failure("Hello World! expected but Goodbye found")
In most cases, the call to lit is handled automatically. If a bare string is provided to the functions and operators below, it will be promoted to literal parser whenever possible. Only when an operator is between two Python types, like a string and a string 'a' | 'b' or a string and function '100' > int will this “implicit conversion” not take place and you have to use lit (e.g. lit('a', 'b') and lit('100') > int).
reg(pattern): regular expression parser
Like lit, this matches a string and returns it, but the matching is done with a regular expression.
class IntegerParsers(TextParsers): integer = reg(r'[-+]?[0-9]+') assert IntegerParsers.integer.parse('-128') == Success('-128')
parser > function: conversion parser
Conversion parsers don’t change how the text is parsed�they change the value returned. Every parser returns a value when it succeeds. The function supplied must take a single argument (that value) and returns a new value. This is how text is converted to other objects and simpler objects built into larger ones. In accordance with Python’s operator precedence, > is the operator in Parsita with the loosest binding.
class IntegerParsers(TextParsers): integer = reg(r'[-+]?[0-9]+') > int assert IntegerParsers.integer.parse(-128) == Success(-128)
parser1 | parser2: alternative parser
This tries to match parser1. If it fails, it then tries to match parser2. If both fail, it returns the failure message from whichever one got farther. Either side can be a bare string, not both because 'a' | 'b' tries to call __or__ on str which fails. To try alternative literals, use lit with multiple arguments.
class NumberParsers(TextParsers): integer = reg(r'[-+]?[0-9]+') > int real = reg(r'[+-]?\d+\.\d+(e[+-]?\d+)?') | 'nan' | 'inf' > float number = integer | real assert NumberParsers.number.parse('4.0000') == Success(4.0)
parser1 & parser2: sequential parser
All the parsers above will match at most one thing. This is the syntax for matching one parser and then another after it. If working in the TextParsers context, the two may be separated by whitespace. The value returned is a list of all the values returned by each parser. If there are multiple parsers separated by &, a list of the same length as the number of parsers is returned. Like |, either side may be a bare string, but not both. In accordance with Python’s operator precedence, & binds more tightly than |.
class UrlParsers(TextParsers, whitespace=None): url = lit('http', 'ftp') & '://' & reg(r'[^/]+') & reg(r'.*') assert UrlParsers.url.parse('') == \ Success(['http', '://', 'drhagen.com', '/blog/sane_equality/'])
parser1 >> parser2 and parser1 << parser2: discard left and right parsers
The discard left and discard right parser match the exact same text as parser1 & parser2, but rather than return a list of values from both, the left value in >> and the right value in << is discarded so that only the remaining value is returned. A mnemonic to help remember which is which is to imagine the symbols as open mouths eating the parser to be discarded.
class PointParsers(TextParsers): integer = reg(r'[-+]?[0-9]+') > int> integer << ',' & integer << ')' assert PointParsers.point.parse('(4, 3)') == Success([4, 3])
In accordance with Python’s operator precedence, these bind more tightly than any other operators including & or |, meaning that << and >> discard only the immediate parser.
- Incorrect: entry = key << ':' >> value
- Correct: entry = key << ':' & value
- Also correct: entry = key & ':' >> value
- Incorrect: hostname = lit('http', 'ftp') & '://' >> reg(r'[^/]+') << reg(r'.*')
- Correct: hostname = lit('http', 'ftp') >> '://' >> reg(r'[^/]+') << reg(r'.*')
- Better: hostname = (lit('http', 'ftp') & '://') >> reg(r'[^/]+') << reg(r'.*')
opt(parser): optional parser
An optional parser tries to match its argument. If the argument succeeds, it returns a list of length one with the successful value as its only element. If the argument fails, then opt succeeds anyway, but returns an empty list and consuming no input.
class DeclarationParsers(TextParsers): id = reg(r'[A-Za-z_][A-Za-z0-9_]+') declaration = id & opt(':' >> id) assert DeclarationParsers.declaration.parse('x: int') == Success(['x', ['int']])
rep(parser) and rep1(parser): repeated parsers
A repeated parser matches repeated instances of its parser argument. It returns a list with each element being the value of one match. rep1 only succeeds if at least one match is found. rep always succeeds, returning an empty list if no matches are found.
class SummationParsers(TextParsers): integer = reg(r'[-+]?[0-9]+') > int summation = integer & rep('+' >> integer) > lambda x: sum([x[0]] + x[1]) assert SummationParsers.summation.parse('1 + 1 + 2 + 3 + 5') == Success(12)
repsep(parser, separator) and rep1sep(parser, separator): repeated separated parsers
A repeated separated parser matches parser separated by separator, returning a list of the values returned by parser and discarding the value of separator. rep1sep only succeeds if at least one match is found. repsep always succeeds, returning an empty list if no matches are found.
class ListParsers(TextParsers): integer = reg(r'[-+]?[0-9]+') > int> repsep(integer, ',') << ']' assert ListParsers.my_list.parse('[1,2,3]') == [1, 2, 3]
- Author: David Hagen
- Keywords: parser combinator
- License: MIT
- Categories
- Development Status :: 5 - Production/Stable
- Intended Audience :: Developers
- License :: OSI Approved :: MIT License
- Operating System :: OS Independent
- Programming Language :: Python
- Programming Language :: Python :: 3
- Programming Language :: Python :: 3.3
- Programming Language :: Python :: 3.4
- Programming Language :: Python :: 3.5
- Programming Language :: Python :: 3.6
- Topic :: Software Development :: Libraries
- Package Index Owner: drhagen
- DOAP record: parsita-1.1.1.xml | https://pypi.python.org/pypi/parsita | CC-MAIN-2017-13 | refinedweb | 1,589 | 57.98 |
The practices outlined in this section focus on client performance. That is, we assume there is a client application, probably being used by an end user , which talks to a server using RMI. The goal of these practices is to improve both the performance and the perceived performance of the client application.
Perceived performance is a strange thing. The goal in improving perceived performance is improving application responsiveness. That is, when the user clicks a button, the application does the right thing, and it does the right thing quickly . Most practices that improve performance also improve perceived performance. But the converse is not true ”improving application responsiveness can actually degrade overall performance, or at least cause the server to work harder. But that's often a price worth paying if it means the end user is happier .
This section isn't as RMI-specific as the previous two sections because, when you get right down to it, all enterprise applications have a fairly similar structure, and a lot of optimization practices are fairly general.
One of the practices in Section 6.2 was entitled "Always Use a Naming Service." This is sound advice ”it does make the application more robust. When followed na vely, it also makes the application much slower. If you simply replace a remote method call (to a server) with two remote method calls (one to the naming service and then one to the server), you deserve whatever criticism comes your way.
A much better solution is to implement a centralized cache for stubs for remote servers. This cache should meet the following requirements:
It takes logical arguments, such as server names , and returns a stub. As much as possible, the rest of the code should not know about the structure of the application or the location of individual servers. Code is much more robust, and much easier to read, when knowledge about the application topology is encapsulated.
If the cache doesn't have a stub already, it fetches the stub (and does so in a way that's transparent to the rest of the application).
The cache expires stubs that haven't been used in a while. Otherwise , the cache will keep remote server stubs until the client application shuts down. Because having a live stub counts as a reference to the distributed garbage collector, holding on to stubs for long periods of time effectively prevents the server JVM from cleaning up unused resources.
It has a way for you to flush bad stubs (e.g., stubs to servers that no longer exist). When you discover that a stub is bad (e.g., attempting to make a remote call on the associated server consistently throws an instance of RemoteException ), you should remove the stub from the cache right away, instead of waiting for it to expire.
If you implement a stub cache that meets these four criteria, remote method call invocations will look like the following code snippet ( assuming that your implementation of a cache has get and remove methods ):
try { MyServer stubToRemoteServer = (MyServer) cache.get(LOGICAL_NAME_FOR_SERVER); stubToRemoteServer.performMethod( . . . ); } catch {RemoteException remoteException) { cache.remove(LOGICAL_NAME_FOR_SERVER); }
This has many benefits. For one, it's clear code. If the cache has the stub (e.g., if any part of the application has already talked to the server in question), the naming service is bypassed. And if the stub points to a server that is no longer running, the stub is immediately removed.
The next step in using a stub cache is to integrate it with the retry loop discussed earlier. Here's a very simple integration to illustrate the idea:
public void wrapRemoteCallInRetryLoop( ) { int numberOfTries = 0; while (numberOfTries < MAXIMUM_NUMBER_OF_TRIES) { numberOfTries++; try { MyServer stubToRemoteServer = (MyServer) cache.get(LOGICAL_NAME_FOR_SERVER); doActualWork(stubToRemoteServer); break; } catch (RemoteException exceptionThrownByRMIInfrastructure) { cache.remove(LOGICAL_NAME_FOR_SERVER); reportRemoteException(exceptionThrownByRMIInfrastructure); try { Thread.sleep(REMOTE_CALL_RETRY_DELAY); } catch (InterruptedException ignored) {} } } }
This attempts to get the stub and then makes the remote call. If the call fails, the stub is flushed and, on the second try, a new stub is fetched from the naming service. This is good. In most cases, the cache has the stub, and the overhead of the cache is strictly local. In return for the overhead of maintaining a local cache, you've eliminated most of the calls to the naming service.
Using a stub cache inside the retry loop also lets you gracefully handle the cases when a server is restarted or migrated . In these cases, the stubs in the cache won't work, and attempting to use them will cause instances of RemoteException to be thrown. Logically, the client performs the following sequence of operations:
The client fetches the stub from the cache and attempts to make a remote method call.
The call fails because the server the stub references is no longer running.
The client removes the stub from the cache.
The retry loop kicks in, and the client tries again.
Because the cache is empty, the cache fetches a new stub from the naming service.
Because the new stub points to the new server, everything succeeds.
Combining a stub cache with a retry loop is both efficient and robust!
At one company for which I worked, my first task was described in the following way: "This call is too slow. See if you can make it faster."
I looked at the call. It was slow. It involved 18 separate modules on the server and implicitly depended on about 40,000 lines of code, and all I could think was, "Oh yeah. I'll optimize this in my first week on the job."
Because the task was impossible , I decided to cheat. I thought, "Hmmm. If I can't make the call faster, I can at least use a cache to try and make the call less often." This turned out to be good enough for the application in question, and is often good enough in distributed applications.
The benefits of caching return values on the client side are:
Instead of making a call to the server, which involves network and marshalling overhead, you retrieve the value from an in-process cache. Unless you're doing something truly stupid, this should be faster.
In addition to the performance benefit, looking in a local data structure is more reliable than calling a remote server, and it has a predictable level of overhead (unlike a remote method call, which can take more time if the network is busy).
Bandwidth is the scarcest resource for distributed applications because it is shared by all distributed applications, and because upgrading a network is a lot harder than upgrading a single server. If you don't make a remote call, you aren't using the bandwidth necessary to make the remote call.
If you don't call the server, the server doesn't have to handle the call, which means you've lowered the effective load on the server.
On the other hand, caching does have some major drawbacks. The two most significant are:
Whenever you cache data, you run the risk of the cached values being incorrect. Sometimes this isn't very important. Sometimes it is. Generally speaking, the more important a piece of information is, or the more time-sensitive it is, the less likely you are to cache it.
Within a given sequence of operations (for example, responding when a user clicks a button), a cache improves performance. But caches have to be maintained : data has to be checked for consistency and occasionally thrown out.
Cache maintenance is usually done in a background thread so that a main thread doesn't take the hit of maintaining the cache (otherwise, perceived performance would suffer, and the "more predictable" item listed as an advantage would be false ). But nonetheless, if you're not accessing data that's been cached very often, the client-side cache might very well be a net loss in performance.
This last item is somewhat paradoxical in that, even if the cache winds up costing you more processing time than it saves, it still might be viewed as a performance improvement. This is because the cost occurs in a background thread, but the performance improvements occur in a main thread (where performance improvements are likely to be noticed).
Caching is a subtle and tricky subject. One reference worth looking at is the series of data expiration articles I wrote for onjava.com. In addition, if you're interested in the subject, you might want to keep an eye on JSR-107, the "Java Temporary Caching API," at.
I once had lunch with a group of programmers who were visiting my company from Germany. They were from a company that was partnering with the company I was working for. We were supposed to use CORBA to handle the method calls from their system to ours. But there was a problem.
"CORBA," they confided to me, "doesn't work. It's much too expensive. It doesn't scale very well at all." I was a little surprised by this. I'd been using CORBA for a couple of years at that point, and I'd never run into scalability problems (at least, not at the scale we were talking about).
It turned out that their idea of "building a distributed application" was to "build a single-process application using standard object-oriented techniques and then stick the network in." Their testing had revealed that if an instance of Person is on one machine, and the user interface displaying information about the person is on another machine, a sequence of fine-grained calls such as getFirstName( ) , getLastName( ) , and getSSN ( ) to get the values to display on the screen has performance problems.
Once I figured out what they were complaining about, I had a solution: "Don't do that." The object decompositions that make sense in a single-process application often don't make as much sense in a distributed application. Instead, you need to carefully look at the intent behind sequences of calls and see if you can encapsulate a sequence of calls in one bigger method call (which I refer to as a batch method).
In the previous example, the sequence getFirstName( ) , getLastName ( ), getSSN ( ), . . . should really have been a call to a new method called getDisplayData( ) . Of course, getDisplayData( ) shouldn't exist for a single-process implementation of the Person class (it completely breaks encapsulation). But it has to be there for the distributed application to perform well, and that's the point of this practice.
How do you spot a potential batch method? There's no cut-and- dried way to do so (that I know of). But here are four rules of thumb for when batch methods are appropriate:
The methods you want to include in a batch method must be called in a sequence fairly often. Batch methods are an optimization and they shouldn't be created for uncommon cases.
If the methods are all for data access (with no side effects), a batch method is more likely to be appropriate.
The methods should all block the same task (and not distinct tasks). If all the method calls are associated with the same set of client-side conceptual tasks, and none of the tasks can continue until the client gets all the return values, a batch method is almost certainly appropriate.
The methods have a predetermined outcome. That is, the client will make a sequence of calls. If the client doesn't know all the arguments (for all the calls) at the time the first call is made, or if the return values for all the calls can't be computed at the time when the first call is made, the methods can't be grouped into a batch method.
Sometimes a client will make a series of calls to a server, and these calls, while conceptually a transaction, aren't easily batched, or don't feel like a batch method. A classic example of this is transferring money between two bank accounts.
If you have two distinct servers (one for each account), this involves the following four steps:
Opening a transaction (presumably using a transaction management server)
Withdrawing money from one server
Depositing the money in another server
Committing the transaction
This sequence of calls should not be executed from a client application for two reasons. The first is that client applications are often deployed across a WAN, which is slow ( especially compared to a datacenter managed by IT personnel). Making four concurrent remote method calls under those conditions could lead to significant performance problems.
The second reason is that logic about transactions will most likely change. Even something as simple as "We've decided to log all money transfers from now on" would force you to redeploy a new version of the client that would call a logging method on a server somewhere, which is very bizarre in and of itself.
The solution is to use a server-side proxy for the client. A server-side proxy is a server, running "near" the other servers, which is client-specific and whose sole role is to manage complex transactions for the client. If you're using a server-side proxy, the previous calling sequence turns into a single call to the proxy's transferMoney method. The proxy still has to perform the four remote method calls, but it does so on a LAN inside a well-managed environment. Figure 6-1 illustrates the trade-off.
Most remote method calls are synchronous: the calling thread stops and waits for a response from the server. An asynchronous method call is one in which the caller doesn't wait for a response, or even wait to know if the call succeeded. Instead, the calling thread continues processing.
RMI doesn't directly support asynchronous calls. Instead, you have to use a background thread to make the call. In Example 6-2, the calling thread creates a command object and drops it off in a background queue for execution. This leaves the calling thread free to immediately resume processing, instead of waiting for a response, as in the following code snippet:
BackgroundCallQueue_backgroundQueue = new BackgroundCallQueueImpl( ); // . . . _backgroundQueue.addCall(new SpecificCallToServer( . . . ));
Example 6-2 is a sample implementation of BackgroundCallQueue and BackgroundCallQueueImpl .
public interface BackgroundCallQueue { public void addCall(RemoteMethodCall callToAdd); } public class BackgroundCallQueueImpl implements BackgroundCallQueue { private LinkedList _pendingCalls; private thread _dispatchThread; public BackgroundCallQueueImpl ( ) { _stopAcceptingRequests = false; _pendingCalls = new LinkedList( ); _dispatchThread = new Thread(this, "Background Call Queue Dispatch Thread"); _dispatchThread;.start( ); } public synchronized void addCall(RemoteMethodCall callToAdd) { _pendingCalls.addCall( ); notify( ); } public void run( ) { while (true) { RemoteMethodCall call = waitForCall( ); if (null!=call ) { executeCall(call); } } } private synchronized RemoteMethodCall waitForCall( ) { while (0== _pendingCalls.size( )) { wait( ); } return (RemoteMethodCall) _pendingCalls.removeFirst( ); } private void executeCall(RemoteMethodCall call) { // . . . } }
This isn't very complicated code, but it does offer two very significant advantages over synchronous method calls. The first is that it decreases the time a main thread spends sending remote messages. Imagine, for example, that a user clicks on a button, and, as a result of that click, the server needs to be told something. If you use a synchronous method call, the button processing time (and, hence, the perceived performance of the application) will include the time spent sending the remote method call (and the time the server spends processing the call). If you can make the call asynchronously, in a background thread, the application isn't any faster or more efficient, but the user thinks it is.
The second reason is that, once you've moved to a model where requests are dropped off into a queue, you can tweak the queue and make performance improvements without altering most of the client code. For example, if you are making a lot of calls to a single method on a server, you can group these calls and make them in a single call. For example, instead of 100 calls to:
server.patientGivenMedication(Patient patient, Medication medication, long time, HealthCareProvider medicationSource);
you might have 1 call to:
server.patientsGivenMedication(ArrayList medicationEvents);
Because each remote method call contains information about all the relevant classes involved, this will dramatically reduce both marshalling time and bandwidth. Instead of marshalling and sending information about the Patient class 100 times, you will send it only once.
There are two major downsides to putting messages in a background queue. The first is that your code will be harder to debug. Decoupling the source of the remote method call from the time the remote call is made makes it harder to trace the source of logical errors. For example, if a command object has the wrong value for an argument, it's harder to track down the source of the error.
The second problem with putting messages in a background queue is that it's harder to report failures (and harder to respond to them). If a user clicks a button and therefore thinks of an operation as "done," it can be disconcerting for him to find out later on that the operation failed.
Given all this, the question is: when should you use asynchronous messaging? Here are three indicators that a method can be put safely into a background queue:
If the method returns void and throws no exceptions (other than RemoteException ). Methods with this sort of signature tend to be information-sending methods rather than information-retrieval methods or methods that are requesting an action. And, hence, they can be safely postponed and performed in the background.
If there is an associated method to find out the status of an operation at a later time. For example, consider a method to submit a print request to a print server. It might have a boolean return value, and it might throw all sorts of interesting exceptions. But having clicked on the Print button, the user really wants to be able to continue with his work, not wait until the method call transfers the entire file to the print server, and he wants a status view so that he can see where his document is in the print queue.
If the server can call the client back with a return value (or an exceptional condition). Certain requests aren't particularly urgent and can be performed in the background. But the user would like to know if he succeeded. Consider email, for example. When he clicks on the Send button, the user is really saying, "This can go off into the email cloud now." Whether it is sent now or three minutes from now is not really an issue. But he is assuming that if it can't be sent, he will be told.
Printing documents is also a case when callbacks can improve the user interface. A callback to let a user know that his document has been printed is a nice feature.
Using callbacks to let the user know the outcome of an event could incur some additional overhead. It replaces one bidirectional socket connection (the method call and then the return value) with two unidirectional connections (the method call is sent and then, in a later connection, the response is sent). Breaking apart messages like this is a useful technique for optimizing perceived performance, but it almost always incurs some extra overhead. | https://flylib.com/books/en/3.299.1.38/1/ | CC-MAIN-2021-17 | refinedweb | 3,194 | 61.87 |
...Read More »
Monitoring ...Read More »
Parameterized Test Runner in JUnit
We all have written unit tests where in a single test tests for different possible input-output combinations. Lets look how its done by taking a simple fibonacci series example. The below code computes the fibonacci series for number of elements mentioned: import java.math.BigInteger; import java.util.ArrayList; import java.util.List; public class Fibonacci{ public List<Integer> getFiboSeries(int numberOfElements) ...Read More »
How »
Infeasible software projects are launched all the time
Infeasible software projects are launched all the time and teams are continually caught up in them, but what is the real source of the problem? There are 2 year actual projects for which the executives set a 6 month deadline. The project is guaranteed to fail but is this due to executive ignorance or IT impotence? There is no .. »
Route 53 Benchmark: The New AWS Geolocation’s Surprising Results
Latency »
The anatomy of Hibernate dirty checking ...Read More » | https://www.javacodegeeks.com/page/365/ | CC-MAIN-2017-04 | refinedweb | 162 | 50.12 |
0
I'm trying to get a calculation done in a loop but don't want it to print until after all loop are done. It will print but the calculation isn't done. Please help.
import java.util.*; public class FlipCoin { public static void main(String[] args) { String choiceString; final String HEADS = "Heads"; final String TAILS = "Tails"; int coinToss = 1; double result; int heads = 1; int number = heads + 1; int percentage1 = number * 10; int percentage2 = 100 - percentage1; while(coinToss <= 10) { result = (Math.random()); if(result <= .5) { choiceString = HEADS; heads = 1; } else choiceString = TAILS; System.out.println("Cointoss " + coinToss + " came up " + choiceString); coinToss++; number = heads + 1; } System.out.println("The percentage of tosses that were heads is " + percentage1 + "%" + "\n& the percentage of tosses that were tails is " + percentage2 + "%"); } }
Edited by mike_2000_17: Fixed formatting | https://www.daniweb.com/programming/software-development/threads/211907/calculation-in-a-loop | CC-MAIN-2018-22 | refinedweb | 133 | 51.38 |
User talk:Stevo
Hello and welcome. Keep the discussions on the same page, etc...
Welcome to RationalWiki 2.0! -Ĭ₠ŴΣĐĝё 16:33, 17 June 2007 (CDT)
- Thanks Ice, I'm a fan of your work. BTW, what's this '2.0' business about? --Stevo 16:40, 17 June 2007 (CDT)
Contents
User Page[edit]
I dunno what the Gods of 2.0 will think of your new page, but is there a way you can leave the tabs (discussion, history) clickable? I think, though, that you may be deserving of a 5 minute block for trying to bring back minimalism. No one likes the 80s. ;) αιρδισΗταλκ 11:20, 19 June 2007 (CDT)
- But I liked it for its minimalist whiteness! Ok, I'll change it back for the mo --Stevo 11:22, 19 June 2007 (CDT)
- I liked it too - it's just getting to your talk page might be annoying - maybe have whited-out links that work when you roll over them? I wouldn't worry too much, was more a welcome than a warning (or was intended to be - the user page is your castle or some such thing somewhere in the rules...) αιρδισΗταλκ 11:29, 19 June 2007 (CDT)
- Thanks :) Well i'll work out something later... --Stevo 11:35, 19 June 2007 (CDT)
- If you want to make your user page tabs unusable, you could just add a "talk" link to your sig, making it easy to get here. Just an idea. Of course, anyone savvy can edit the url in their browser... humanbe in 14:20, 23 June 2007 (CDT)
-
- I dig the intense whiteness and nothingness. It inspires me to fill my mind.--PalMD-yada yada 12:36, 19 June 2007 (CDT)
Isn't minimalism more of a '60s than an '80s thing? I don't remember the '80s as particularly minimalist, to the extent that I remember them at all. --AKjeldsenGodspeed! 12:59, 19 June 2007 (CDT)
- The 80's were more of "le siecle de la chevre" than anything.--DoxXox-DawkT0wk 13:11, 19 June 2007 (CDT)
- Tous les siècles sont des siècles de la chèvre! --AKjeldsenGodspeed! 13:14, 19 June 2007 (CDT)
- I can just remember white rooms and no furniture from 80s movies. or i saw american psycho last week for the first time with it's white walls and little furniture. I was thinking interior design rather than art, but i may still be wrong. δαιισρΗταλκ 13:16, 19 June 2007 (CDT)
- The rooms were mostly bare because we'd just got finished tearing down all that fake wood panelling and tossing out the hammered metal sculptures and string art from the '70s. The 80's were all about bright primary colours and geometric shapes, as I recall. And big hair. But not Utah Mormon type big hair. Go watch a couple of Pat Benetar videos as penance. --Kels 15:14, 19 June 2007 (CDT)
OK, well by, er, popular demand, it's back, but with a link to my talk page :) --Stevo 14:17, 19 June 2007 (CDT)
- This guy's got skillz. Wonder if he's a friend of ice--PalMD-yada yada 14:16, 19 June 2007 (CDT)
- Sadly no, I don't know the great IceWedge. --Stevo 15:07, 19 June 2007 (CDT)
- Tis better energy-saving wise (i presume) but far too messy. i'll stick with what i have, for now. δαιισρΗταλκ 16:53, 19 June 2007 (CDT)
your help[edit]
we seem suddenly to have an embryonic index of who is good at what (see the Category Go-To Guys). Do you know of a way that if i put myself in one of these categories, the category box won't appear at the bottom of my user page? some of your blank-out wizardry maybe? δαιισρΗταλκ 17:35, 20 June 2007 (CDT)
- Yes, well indeed, not much consistency with the plurals there. Anyway, thanks, glad it's perfect - just keep that extra div in your page (it can go anywhere in the code) and it should still work if you make changes. --Stevo 18:02, 20 June 2007 (CDT)
- I'll remove it now. δαιισρΗταλκ 18:10, 20 June 2007 (CDT)
Aah, sorry, didn't realise you were a sysop! Thanks --Stevo 18:11, 20 June 2007 (CDT)
- I keep it secret - haven't had to do anything with it yet. no need to delete the page - it's nonexistant, and if we need it we can restore. δαιισρΗταλκ 18:14, 20 June 2007 (CDT)
talk page template & others[edit]
I assume it was you who improved it, since you fixed my talk page use of the template. Thanks! humanbe in 11:01, 22 June 2007 (CDT)
- Yeah sorry I hadn't left a message for you on your talk page but I had replied to you at Template_talk:Talkpage --Stevo 11:04, 22 June 2007 (CDT)
Thanks again, for fixing the VD template so the cat works! Are you the same Stevo I see late at night in "Jackass"? (the movie...) humanbe in 14:23, 23 June 2007 (CDT)
- Haha, someone that would do this (careful) to himself? Hell no! :D --Stevo 17:44, 23 June 2007 (CDT)
Was that you who made the "new archive" thing on the talk page template? That rocks! humanbe in 20:46, 28 June 2007 (CDT)
- Of course :) Glad you like it -- Stevo (talk) 07:42, 29 June 2007 (CDT)
category tech question[edit]
Can you rig a category so it drops the namespace part of an article title? Specifically, category:conservapedia is almost all "C"s because of the namespace prefix. humanbe in 21:16, 24 June 2007 (CDT)
- I'm not Stevo, but it looks like the best we can do is set a sort key for the category; using [[Category:Conservapedia|{{PAGENAME}}]] will do what we want. I've updated the {{conservapedia}} template to use that, and am going through the existing pages making the necessary adjustment. --jtltalk 21:35, 24 June 2007 (CDT)
user page[edit]
nice. δαιισρΗταλκ 10:14, 26 June 2007 (CDT)
Sysops on Wikipedia[edit]
I have no real problem with you removing SharonS and TimS's efforts as they were minimal but I originally posted them under Andy's puffery as they were obviously acting in concert with him. God's peed Babel fishÅЯ†ђŮŖ ÐΣй†Now look here! 15:52, 26 June 2007 (CDT)
- Thanks, well at first I thought they had far to big a mention since all their edits were rather trivial and there was nothing particularly remarkable about them adding to the Conservapedia article, which is why I cut down the amount of text on them and moved them to the bottom of the list. Then, while also being slightly squeamish about "attacking" minors in this way, I read the intro to the article again, which declares that the articl's about sysops that have caused trouble etc. on WP, so I felt that there wasn't a case for them being in there. --Stevo (talk) 17:42, 26 June 2007 (CDT)
As jtl has brought up the subject on Conservapedia Talk:Sysops on Wikipedia I've copied these comments over to continue the discussion there --Stevo (talk) 17:47, 26 June 2007 (CDT)
Thanks![edit]
...for categorizing. Have a goat! -αmεσg 09:03, 28 June 2007 (CDT)
- No problem. I'm not much of a writer so I like to help in ways like this. -- Stevo (talk) 09:05, 28 June 2007 (CDT)
"I might tackle the other 4/5ths of the main page next!" Hey, Stevo, why not do it in a sandbox, so you can build the whole thing and tweak it til it's sweet? What we have isn't bad, but I'm not saying it couldn't be better/cooler/faster/have more goats. humanbe in 18:19, 28 June 2007 (CDT)
Yeah might do that. I'm not trying to own it or anything, all I mean is that I'm obsessed with efficiency/cutting out repetition and I'd really like to clean up the templates namespace. So I think the other parts of the main page could work as articles too. -- Stevo (talk) 18:24, 28 June 2007 (CDT)
- OK, then here's what to do - move the tmeplates to the RW article space. That way the history survives. We can't really get rid of the content template because, well, it has a history. And I would recommend waiting until Linus is around, in case the move screws up bigtime due to different namespaces, he might be able to repair it. But creating articles to back up the main page won't get rid of the templates unless a move is done. Anyway, "template:" is a mess already, and will only get worse! humanbe in 18:31, 28 June 2007 (CDT)
- Hey, don't worry, I'd only make suggestions, and let a sysop do the actions (and take the blame :) ). I hadn't heard about problems when moving across namespaces - I'll see if I can find out anything more about that. -- Stevo (talk) 18:48, 28 June 2007 (CDT)
- You have as much right as anyone to make changes. If someone doesn't like it, they'll revert, then we can figure out what to do. I also don't know of any problems moving across namespaces, and we've done a lot of it (all the fun: and Recipe: moves, frex). --jtltalk 19:32, 28 June 2007 (CDT)
- None of those changes were across... hmm, wait, yes. We moved from main to temp, then renamed temp. So where did I read about problems with moving across namespaces? Lets assume I'm wrong, since I'm not exactly a wiki-wizard. I'd recommend a temporary mainpage made with no templates, then move the templates to RW and try it out on a sandbox version of the mainpage. If it works, alter the dummy mainpage back to the new RW space sources. Just my 0.02 in terms of keeping things running while you work. And, I suppose jtl is right, we can fix anything that breaks. Well, I am trusting that while I might have access to how to fix things, he knows how!
- And, duh, to clear the template space, that content one can always be moved to RW as "copy of old featured contents file".
- Oh, I remember where I read about the moving across thing. It was "somwhere" in the mediawiki instructions. Don;t worry about my worries, jtl is savvier about the wiki software than I. I = not; jtl = quite a bit. humanbe in 20:16, 28 June 2007 (CDT)
- Just from a quick search, was this what you had read? -- Stevo (talk) 20:26, 28 June 2007 (CDT)
Great Work![edit]
Just want to congratulate you on this! ɧєɭıסş-get sunburn! 04:16, 2 July 2007 (CDT)
- TVM, glad to help. Just say if you think of any improvements or anything (or do them yourself of course) -- Stevo (talk) 17:28, 2 July 2007 (CDT)
- Hey Stevo, quick question, when will the content be back "in" RationalWiki_talk:Community_Standards?
- Oh, and nominated you to be demoted to sysop at RationalWiki:Requests for Sysop, I figure the extra tools would come in handy with the sort of thing you do so well here! humanbe in 15:22, 5 July 2007 (CDT)
- Thanks for the nomination. I'm just taking some time to write a reply to you about the blocking, and then I'll get to sorting out community standards. -- Stevo (talk) 15:27, 5 July 2007 (CDT)
- There seemed to be nothing on RationalWiki Talk:Community Standards that was recent/important so I've left it in the temporary archive with a link to it on the page. I'll sort out the rest of the stuff over the next couple of days. Hopefully we'll be able to put a block policy on the article page in that time! -- Stevo (talk) 16:00, 5 July 2007 (CDT)
ah, a reality check[edit]
Jeb is back... Special:Contributions/Jeb_Berkeley.
How about I let you do any cleanup needed, if he needs a block as a sysop? Or, I could make you one (with post-approval by others) so you can do it yourself? humanbe in 16:14, 5 July 2007 (CDT)
- Sorry as a non-sysop I don't have the rollback tools. I wouldn't argue with being made a sysop, though wikiinterpreter seems to be handling it at the moment. -- Stevo (talk) 16:19, 5 July 2007 (CDT)
- Compared to Icewedge, this guy's rubbish. It's funny watching him get so cross! (and if he's a parody, he's laughing with us) --ויִכִּ נתֶּרֶפּרֶתֵּר שְׁלֹום!
- Definitely a C- for wandalism. Must try harder/see me. liessmokemirrors 16:22, 5 July 2007 (CDT)
- Well, I shut him down for 8 hours for calling people "fags" and "faggots". Cleanup on aisle six, please, if any is required. And feel free to discuss the block on his talk page, however you feel. humanbe in 16:25, 5 July 2007 (CDT)
- Although the sequence has been disrupted 8 hours seems about right so I can't disagree with that. -- Stevo (talk) 16:55, 5 July 2007 (CDT)
Demotion[edit]
Apparently, condolences are in order, as I have successfully demoted you to "sysop". You will now find a few extra buttons that are very useful in the right hands, such as "delete" and "block". I hope you use your awesome powers for gud and not evul! humanbe in 17:33, 5 July 2007 (CDT)
- Damn well I guess you'll be seeing how I fare now! Just a warning that I'll be going to bed soon for if Jeb comes back. But thanks, and one question, what are all the exclamation marks that I now have on my recent changes list? -- Stevo (talk) 17:39, 5 July 2007 (CDT)
- Those are edits that no sysop has "marked as patrolled". Something we are a bit half-hearted about at this point, and should probably do more of. If you go to one you'll see a link that says "mark as patrolled" - it means it isn't vandalism of some sort. PS, I'm sure you'll do very well. humanbe in 17:44, 5 July 2007 (CDT)
- Thanks, I've just tried it out -- Stevo (talk) 06:33, 6 July 2007 (CDT)
- I don't like all these extra buttons at the top of the pages! I'm too scared of hitting the wrong one now :) -- Stevo (talk) 10:18, 6 July 2007 (CDT)
- You'd better not hit the wrong one, or all manner of bureacratic whoopass will rain down on you :-) ДιЯɖі$ɧ ɥοםЄʟβЯƏакĐΩωΝ 10:26, 6 July 2007 (CDT)
Jeb link[edit]
Thanks for catching my error. I was fixing the links for conservatruth and was going to fast for my own good. Good catch! ollïegrïnd 10:11, 6 July 2007 (CDT)
- No problem, it was a good idea to put the permanent links in as you did. Thanks! -- Stevo (talk) 10:13, 6 July 2007 (CDT)
Good code monkey[edit]
And, in general, means what? I hope to see your constructive contributions! !!! humanbe in 00:04, 7 July 2007 (CDT)
wtf?[edit]
"05:00, 7 July 2007, Stevo (Talk | contribs | block) blocked Stevo (contribs) (infinite, account creation blocked) (Bye)" (emphasis mine)
Say it ain't so, Joe. Or are you just on holiday? humanbe in 21:02, 12 July 2007 (CDT) | https://rationalwiki.org/wiki/User_talk:Stevo | CC-MAIN-2021-31 | refinedweb | 2,609 | 79.6 |
Summary: Microsoft Office Word 2003 can support documents with XML schemas, allowing you to save, manipulate, and even create documents as well-formed XML documents. To make it easier to exploit these capabilities, you can download a free toolbox that assists you in working with the new XML features of Word. This article introduces the Microsoft Office Word 2003 XML Toolbox and explains its benefits for developers. The Word XML Toolbox is available as a download from the Microsoft Download Center. (16 printed pages)
John R. Durant, Microsoft Corporation
February 2004
Applies to: Microsoft Office Word 2003
Download WordXMLToolbox.msi.
Contents
Creating Custom Tags Using Office 2003
Word XML Scenario
Adding XML Tags
Creating the Schema
Adding Placeholder Text
Inserting XML into the Document
Monitoring XML Events
Viewing XML
Familiarizing Yourself with Dialog and Task Pane Shortcuts
Applying Cool Colors
Conclusion
Using XML, you can create custom tags that enable users to organize and work with documents and data in innovate ways using Microsoft Office Word 2003. For example, a special document used in the hiring process, while filled in by a user in the normal way, can offer up its contents as discretely accessible data elements. You can send the information off to a database or integrate it with some other external system. At the heart of the XML features of Word is the ability to liberate user content from the confines of the document so it can be re-purposed in ways that are meaningful to a specific organization. You can associate XML schemas, a key part of XML support in Word, with a document so that its contents are clearly organized and even validated according to the data definition contained in the schema.
XML features, except for saving documents as XML with the Word XML schema, are available only in Microsoft Office Professional Edition2003 and stand-alone Microsoft Office Word2003.
All of these features are great, but the actual features (menus, shortcuts, etc.) of Word are designed for end-users not for developers when creating Word-based solutions. In other words, as a developer, you may find working with the dialogs and so forth a little slow going. Fortunately, you can download and install the XML Toolbox for Microsoft Office Word 2003. It's free, and its sole purpose is to make life easier for developers. Go to the Office Developer Center Tools and Utilities to find the link for this and other key tools that can help you developing with Office. After the toolbox is installed, the Word XML Toolbox toolbar appears (Figure 1). You can hide or show the toolbar by going to the View menu, clicking on Toolbars, and then selecting the Word XML Toolbox item from the list.
Remember that the toolbox only works with Microsoft Office Word 2003. In addition, the toolbox makes heavy use of the Microsoft .NET Framework and requires that .NET Programmability Support is enabled on your development computer prior to attempting to install or run the toolbox.
For more information about installing .NET Programmability Support, see Installing the Office Primary Interop Assemblies.
To help present the benefits of the XML toolbox, I list and describe a series of developer scenarios. Then, I show how the Word XML Toolbox can help make the job easier. Some of the scenarios are admittedly a bit contrived, as they are necessarily simplified versions of some of the larger problems we developers really face. Nevertheless, I believe the benefits of the toolbox come through. A few of the scenarios are not elaborate at all, as they are designed to show how the toolbox solves a rather basic little problem such as too many clicks to get to a relevant dialog box.
The boss did some reading and finally understands how great the XML support in Word is and wants to start reaping some benefits. Working for a small newspaper, your task is to create a template that allows writers to continue writing their content in Word, but ensure that the content conforms to a schema. This schema increases the accuracy and completeness of the content, and it allows you to extract the content once it is finalized. Furthermore, the schema can even allow an automated system to pull content blocks from a database and create the sketch of an article in Word automatically so that the writer can further refine and amend it.
Dutifully, you open Word, create a blank document, and then stare at the blinking cursor. What is the next step? Your task boils down to creating an XML schema that reflects the needs of your organization, and then creating a Word document with XML tags in it that correspond to the XML schema. You could fire up an XML editor (everything from Notepad to Microsoft Visual Studio .NET 2003 or a third-party tool) and start creating the .xsd file from scratch. It's not a bad approach, and for elaborate schemas, a good XML editor is the right tool for the job. However, using the XML Toolbox, you can begin laying down some XML tags and deriving a schema right inside of Word.
To get started, just start typing some XML tags in a document, arranging them in the order that you want them. Figure 2 shows the document and one way to order the XML tags.
At this point, the XML tags may look like XML to you, but Word thinks of them as regular text. They are not yet identified as real XML tags so that Word responds to them as full-fledged XML in a structured document rather than just ad hoc textual input. To convert the text to true XML, on the XML Toolbox menu, click Convert <Tags/> to XML Nodes as shown in Figure 3.
After the conversion, what was previously identified as text appears as XML recognized by Word. The result is shown in Figure 4.
At this point, the project is shaping up nicely. You now have a document with XML tags in it. The tags are named and arranged in such a way that they reflect the business requirement for article authoring. However, some changes are needed. First, the last three tags really ought to be part of the <body> node. That way, a conclusion cannot be written that is not part of the actual body and all of the text for the article can be accessed as a complete unit rather than having to be continually assembled from three smaller units. To make this change, you can highlight the last three nodes and drag them into the <body> node.
While arranging XML nodes is a large part of the overall task, this document is still not associated with a schema. This scenario requires that you create an explicit schema to use for other documents and even by a completely different system to auto-generate documents from external content sources. The Word XML Toolbox includes a feature that allows you to generate an inferred schema.
First, you need to save the document. Because you are trying to create a template for later use, you should save it as a document template. Then, on the Word XML Toolbox toolbar, click Generate Inferred Schema. The toolbox presents you with a dialog box (Figure 5) wherein you provide the root for the schema, its namespace and final file path.
Once you create the file, the toolbox provides a dialog box informing you that the process is complete, and it generates a new document with the schema already associated. In this example, the schema is as follows:
<?xml version="1.0" encoding="utf-8"?>
<!--Schema generated by the Word XML Toolbox for Microsoft Office Word 2003-->
<xs:schema xmlns:tns="schemas-customArticleSchema"
attributeFormDefault="unqualified" elementFormDefault="qualified"
targetNamespace="schemas-customArticleSchema"
xmlns:
<xs:element
<xs:complexType
<xs:sequence>
:schema>
The Word XML Toolbox also adds the schema to the Word schema library after inferring the schema and saving it in a separate file.
The schema library allows you to specify the namespaces that are available for your document or solution. You can also configure options, such as set the friendly names (aliases) for schemas and any XSLT files that are associated with a schema. Schemas in the schema library are available to attach to a document and are listed on the XML Schema tab of the Templates and Add-ins dialog box.
Once the schema appears in the schema library, you can add it to the template solution. To do this, make sure the template document is active and choose Templates and Add-ins to see the list of schemas currently available. Select the box next to the schema you just created and in the Schema validation options section, check the box next to Validate document against attached schemas. This associates the template with the schema and makes sure that a document created based on this template validates against the schema. Save the changes to the template.
The solution created in this article saves the template and the schema on the local computer. To make them available to others, you can place them on a publicly available share or SharePoint site.
The solution now has some of the fundamental pieces in place. However, it is not very nice to look at and not very user-friendly. Keep in mind that only in rare cases should a user actually see the XML tags in the document or know much about the underlying schema. Typically, you designate placeholder text for each of the XML tags in the document. Thus, the user sees the placeholder text and knows the information to add at appropriate locations in the document. The Word XML Toolbox includes a tool to change XML attributes for the tags in the document and add placeholder text quickly and easily. To access this tool, on the toolbox toolbar click the XmlNode Property Viewer (Figure 6).
The viewer allows you to move through the nodes in the document and view or change some of its attributes. Figure 7 shows a highlighted XML node and its properties in the viewer. Type the placeholder text as shown and click Next Node >> in the viewer to move to the next node in the document. After making changes to the nodes, close the viewer.
It's now time to see what a user would see when viewing the document without the XML tags showing. Once again, the Word XML Toolbox includes a feature that makes it easy to switch between viewing the documents with the tags displayed and without them displayed. Click Toggle XML Tag View (Figure 8).
The document with placeholder text showing should appear as follows:
You can now format sections of the document with styles and generally set up the document template so that it simplifies the user experience.
Word added XML support to the Range object, one of the most loyal objects in the Word development realm. This is an example of where the new Word XML support blends rather cleverly with the classic Word object model. Thus, you can go after portions (or all) of a document using the traditional Range object but then work with it as XML. The new Range object supports a method called InsertXML that lets you insert arbitrary XML directly into the document. However, there is no user interface for adding XML this way — that is what Word is for after all!
However, developers are a different sort. When developing an XML-based Word solution, you may want to add XML to the document directly, not just text. When would this be useful? To help this make sense, think of our solution that we created thus far. Imagine a schema that has validation that signals invalid text. Imagine also the solution with a smart tag that processes textual input and manipulates the content as XML. One way to test this is to insert some XML in the document and see how the solution responds. The Word XML Toolbox comes with a function that lets you insert XML into a document conveniently. Click Insert XML Dialog (Figure 10) to open the Insert XML Editor (Figure 11).
There are only a few tags you need to worry about when adding XML this way, and adding bolded text is just a hint of how far you can take things. The Insert XML Editor is a .NET Framework-based form that lets you type free-form character strings in it. It is not sophisticated as far as editors go (again, that is for what you use applications such as Word), but it does have a feature to let you undo your insert if it is not what you wanted to see. One caveat is that Word provides limited information about why the InsertXML method may have failed. Thus, if your XML is not well-formed (the most common problem) or some other error occurs, then you need to do your own investigation to figure out what went wrong. Another common error occurs when the inserted XML does not conform to the WordProcessingML (or WordML for short) schemas.
One of the single greatest things about the new XML support in Word is that there are events that fire when XML-related things happen. For example, if an XML node is added that is in the wrong place, an event fires. When a user moves from node to node, events fire. When textual input occurs, events fire. This is overwhelmingly interesting to us as developers because our curious nature always causes us to want to know what is going on when applications are running. However, it also leads ultimately to a better user experience. Trapping these events can be useful when validating input and letting users know what changes need to be made so that content is more accurate and useful.
The following two events pertain to the Document object:
The XMLAfterInsert event fires just after a new element has been inserted
The XMLBeforeDelete event fires just before an element is deleted
These events pertain to the Application object:
XMLValidationError: Fires when a validation error occurs in the document and receives a single parameter: a reference to the node with the error
XMLSelectionChange: Fires when you select a new node. This event receives parameters: the WordSelection object for the newly selected material, references to both the node that lost focus and the node that gained focus, and a reason code
When testing, it would be nice to have a type of "watch" window that lets you know what events are firing, what is causing them to fire, and what messages are pushed up the queue. That is why the toolbox includes the XML Event Monitor, accessible from the toolbar.
This viewer displays a window with a current snapshot of the XML-related events firing in Word. No longer do you need to stub out each event and put in a message box to peek at what is going on under the hood. The XML Event Viewer simplifies things and displays the messages in a tidy grid. Figure 13 shows the viewer with the text of one entry magnified to be more easily seen.
The XML Event Viewer can also be helpful when debugging a solution. A quick look at the output may provide insight about where your solution is failing.
The ability to add XML is important to developers, but so is viewing it. It would inconvenient to save your document and then open an XML editor every time you want to see the XML output of your solution. The Word XML Toolbox lets you see the XML representation of your document any time. Moreover, you have three different ways of seeing the output:
The entire document in WordML (Entire Document (WordML) on the toolbar)
A selected portion of the document in WordML (Current Selection (WordML) on the toolbar)
A selected portion of the document such that only the data are displayed in unadorned XML (Current Selection (Data Only) on the toolbar)
Because this article was created in Word 2003, let us look at this very sentence, viewing it in the last two ways described. All three views are accessible from the XML Toolbox menu. To select a view, click XML Toolbox, point to View XML, and then click desired view. Choosing to view the selection as WordML opens the XML Viewer, a simple form that displays all of the XML as text along with buttons to copy the text to the clipboard or save the text as a file. When viewing a selection as WordML, a lot of style-related information is included with the actual data, so the output is verbose. Here is the last portion of the WordML output that contains our sentence:
<w:body>
<wx:sect>
<w:p>
<w:r>
<w:t>Because this article was written in Word 2003, let us
look at this very sentence, viewing it in the last
two ways described.</w:t>
</w:r>
</w:p>
<w:sectPr>
<w:pgSz w:
<w:pgMar w:top="1440" w:right="1800" w:bottom="1440"
w:
<w:cols w:
</w:sectPr>
</wx:sect>
</w:body>
Viewing just the data of the same selection is shorter because it does not contain the style-related information. However, there is one key difference in using these two views: viewing just the data requires that the sentence reside in an XML node (from your custom-defined schema) in the Word document. Copying the sentence into a node (in this case a node called "data") and then viewing the data yields the following output:
<?xml version="1.0" encoding="utf-8" standalone="no"?>
<data>Because this article was written in Word 2003,
let us look at this very sentence, viewing it
in the last two ways described.</data>
In all cases, you avoid unnecessary steps to view the document in XML.
The XML Toolbox menu includes a handful of shortcuts that save you the trouble of clicking through deeply nested menus in Word. The fact that they are deeply nested is not a big obstacle for end-users because they rarely use the dialog boxes. There are four key shortcuts on the XML Toolbox menu:
Templates Expansion Pack Dialog
Templates XML Schema Dialog
Schema Library Dialog
XML Options Dialog
For more information about each of these dialog boxes, as well as their purpose and configuration options, see the Word help documentation.
The Word XML Toolbox toolbar includes two buttons that also make it easier to get to key features. The first is the XML Structure Task Pane button (Figure 14).
Clicking it causes the target task pane to be displayed. The second is the XML Schema in Templates button (Figure 15) that has the same function as the Templates XML Schema Dialog menu item previously listed.
In this latest version of Word, you can also apply protective restrictions to sections of document. For a specified section of a document, you can grant permission to specific users to edit it and specify the type of editing to allow. For more information, see the Word help documentation.
Even though you can see and alter the document protection settings for a document at the WordML-level, Word actually sets permissions at the range level.
Once again, the XML support in Word does not disappoint as it provides a mechanism for configuring restrictions in WordML directly. However, there is no way to get to the XML level directly through Word. The Word XML Toolbox provides some of this capability through two menu items, one for granting permission to the Everyone security group for all nodes in a document and another for replicating custom permissions on one node to all other nodes in the document.
Looking at Figure 16, you see the document with permissions configured.
The entire document is restricted such that users can only add comments. However, in the section outlined in red a specified user (in this case me) can freely edit the text. The Protect Document pane shows this corresponding information.
Using the Word XML Toolbox, you can replicate the protection settings for one XML node of a document to other sections using XML. The Duplicate Current Node to all Other Nodes menu item duplicates the protection settings of the currently selected XML node to every other leaf node (a node with no children) in the document. When using this feature, the toolbox prompts you to confirm that you want to change the permissions in this way (Figure 17).
Click OK to allow the toolbox to change the permissions throughout the document.
The toolbox has another item, Set All Nodes to Everyone Permission, which grants the Everyone security group the permission to edit every leaf node (a node with no children).
The final, fun feature of the toolbox is the menu item, Choose XML Tag Color. By default, Word uses a pinkish color for the XML tags in the document. The color for the XML tags is the same as that for the smart tags in the document. You can change the color of the XML tags, and the toolbox makes it easy to do so. You can choose among black, blue, green, red, yellow, and the default color. You must restart Word for the change to take effect. While it is not a dramatically helpful feature, it does add a little life to the developer experience.
Working with XML in Word 2003 means many new opportunities for developing with Office. Most users will never know exactly what is going on under the hood with the custom solutions you build. The truth is, if you develop in the right way, they should have no reason for knowing. To make it easier to develop with Word and XML, you can download and starting using the Word XML Toolbox, something designed just for developers. Get started developing your XML-based solution, and leverage the toolbox to get the job done with greater speed and simplicity.
The following are key downloads and articles that you ought to know about when working with XML in Word:
Tools and Utilities on the MSDN Office Developer Center
New XML Features of the Microsoft Office Word 2003 Object Model
Office 2003 XML Reference Schemas
XML in Office on the MSDN Office Developer Center | http://msdn.microsoft.com/en-us/library/bb226699%28office.11%29.aspx | crawl-002 | refinedweb | 3,707 | 59.43 |
26 October 2011 11:35 [Source: ICIS news]
LONDON (ICIS)--US-based Praxair's third-quarter 2011 net profit rose 14% year on year to $429m (€293m) on higher sales and strong growth from manufacturing, metals and chemicals markets, the company said on Wednesday.
Sales for the three months ended 30 September were 14% above the previous year’s quarter at $2.90bn, as demand increased across all geographic regions, it added.
Third-quarter sales rose 1% sequentially from the second quarter due primarily to higher volumes, Praxair said.
Operating profit in the third quarter was up 15% year on year to $632m, reflecting higher volumes and prices combined with Praxair’s cost savings from productivity programmes, it added.
“We are continuing to see solid growth in all geographies with the exception of ?xml:namespace>
“Proposal activity remains at healthy levels and our backlog of large customer projects under construction is at a record $2.7bn, 25% above 2010 levels. Most importantly, we remain confident in our ability to bring growth to the bottom line through our commitment to productivity and flawless execution,” he added.
For the full year of 2011, Praxair expects sales in the area of $11.2bn and diluted earnings per share in the range of $5.40–$5.45.
($1 = €0.72)
For more on Prax | http://www.icis.com/Articles/2011/10/26/9502898/us-praxair-third-quarter-net-profit-up-14-at-429m.html | CC-MAIN-2015-06 | refinedweb | 220 | 62.68 |
[ back from a couple days off... ]
Yes: the apr_xml code is currently set up to just use Expat. However, the
intent is that it can be covers for other XML parsers. In particular, Xerces
and libxml would be great options.
And yes, the API is also based a very lightweight tree structure, rather
than event-based. Adding a second set of APIs to set handlers would be a
Good Thing, so please feel free to submit patches to do so.
The insertion of "DAV:" into the set of namespaces is definitely a negative,
but I haven't bothered to spend time to resolve the issue. That is about the
only DAV-specific thing in the whole set of apr_xml routines. The rest is
generally applicable to other problem domains.
The point is: the code originated as part of mod_dav, but it has been
extracted so that other code can use it (config reading? new modules? etc).
However, somebody just needs to spend a bit of time to sand off the rough
edges and to expand the APIs based on what people may need.
Cheers,
-g
On Thu, May 17, 2001 at 08:07:11AM -0700, Ian Holsman wrote:
> I think it is more than that.
> I was trying to get apr_xml usable as a xml_parser
> the apr-xml api, doesn't provide any hooks so that I can
> be notified when I get an element, (which expat has) and
> is currently hard coded for 'DAV' only.
>
> in order to be usefull it needs a couple more functions
> to set the start handler, namespace (on create) and to navigate
> the tree a bit better.
>
>
> > -----Original Message-----
> > From: Jeff Trawick [mailto:trawickj@bellsouth.net]
> > Sent: Thursday, May 17, 2001 4:37 AM
> > To: Ian Holsman; gstein@apache.org; dev@apr.apache.org
> > Subject: Re: libaprutil.la, libexpat.la, APRUTIL_EXPORT_LIBS
> >
> >
> > Ian Holsman <IanH@cnet.com> writes:
> >
> > > Expat is used by the 'apr_xml' set of routines inside of apr-util
> > > which look hard coded to work only for mod_dav.
> > >
> > > you could always move expat and the apr_xml stuff into the mod_dav
> > > module directory.
> >
> > (I don't know what I'm talking about but) maybe
> > apr_xml_parser_create() needs a parameter to specify the namespace?
> > (Or maybe this is an expat-specific concept and we don't want to tie
> > the apr-util API to expat?)
> >
> > --
> > Jeff Trawick | trawickj@bellsouth.net | PGP public key at web site:
> >
> > Born in Roswell... married an alien...
> >
--
Greg Stein, | http://mail-archives.apache.org/mod_mbox/apr-dev/200105.mbox/%3C20010517135033.F5537@lyra.org%3E | CC-MAIN-2014-52 | refinedweb | 408 | 72.97 |
We kicked off this three part exploration of Behavior Driven Development Using Ruby by diving into RSpec basics. With the knowledge of this comprehensive framework in hand, we walked through a practical example of using BDD practices to develop a simple application. By writing the specs first, we were able to use them to drive the design and ended up with nice, clean code as a result.
Of course, the more complex our needs get, the more we'll want to take advantage of advanced techniques that can help make our lives a little easier. In this final example, I'll cover a grab bag of RSpec features as well as some essential third party tools that will help make your life easier when writing your specs.
Wherever possible, I've used code based on the source package from the second part of this series. Here, I'll mainly be focusing on the specs, so please take a look back at the second article if you're curious about implementation details.
When writing test unit code, I've often put in tests that flunk, just to remind me to implement them later. Usually, this kind of code looks something like this:
class UserTest < Test::Unit::TestCase def test_user_should_have_valid_email_address flunk "write test verifying user's email address" end end
This gives an output something like this:
1) Failure: test_user_should_have_valid_email_address:5 write test verifying user's email address.
This works absolutely fine for its purpose, but definitely doesn't look like it is made for this sort of thing. RSpec handles this issue in a clever way, automatically detecting empty examples as not yet being implemented. Therefore, the same functionality could be mirrored like this:
describe "user" do it "should have a valid email address" end
The output for something like this is quite nice, by comparison:
Finished in 0.03517 seconds 1 example, 0 failures, 1 pending Pending: user should have a valid email address (Not Yet Implemented)
With this in mind, we can actually flesh out a simple outline of what tests are needed for the user interface code that I snuck into the source package untested a couple weeks ago:
require File.join(File.expand_path(File.dirname(__FILE__)),"helper") require "#{LIB_DIR}/interface" describe "An interface" do it "should prompt for players" it "should prompt for grid size" it "should be able to update board display" it "should display a score board" it "should prompt for a players move" end
This code, when run, yields a nice report of the work to be done:
PPPPP Finished in 0.010666 seconds 5 examples, 0 failures, 5 pending Pending: An interface should prompt for players (Not Yet Implemented) An interface should prompt for grid size (Not Yet Implemented) An interface should be able to update board display (Not Yet Implemented) An interface should display a score board (Not Yet Implemented) An interface should prompt for a players move (Not Yet Implemented)
It goes without saying that any initial set of specifications is going to change drastically once you start fleshing it out, but it's really nice to be able to annotate your intentions like this, and encourages you to start writing specs right away.
Very few developers like "breaking the build" by checking in failing tests. The policy varies from project to project, but typically failing tests are not committed to the main line of development, or are at least commented out upon commit.
This is risky business, because it means that things can easily be forgotten. However, RSpec offers a way to mark bits of code as pending, which allows you to hide their failure messages but still have a note about them show up in your reports.
Here's a simple demonstration of how that works:
describe "the answer" do before :each do @answer = 0 end it "should be 42" do pending("We need to wait 7.5 million years") do @answer.should == 42 end end end
When this code is run, our report looks like this:
P Finished in 0.037488 seconds 1 example, 0 failures, 1 pending Pending: the answer should be 42 (We need to wait 7.5 million years)
The interesting thing is really that when someone comes along and fixes the problem, it will show up as a failure in your report, e.g., changing the setup so that
@answer = 42 results in this output:
F 1) 'the answer should be 42' FIXED Expected pending 'We need to wait 7.5 million years' to fail. No Error was raised. /Users/sandal/Desktop/foo.rb:11: /Users/sandal/Desktop/foo.rb:4: Finished in 0.034342 seconds 1 example, 1 failure
In more practical usage, this construct might be a good way to mark code that is broken but perhaps has a workaround for it elsewhere in your system or code that has a ticket that should be closed when the bug is fixed.
When the examples pass, a failure will show up, and this will serve as a reminder that the
pending() call can be removed and that some action might be necessary based on what the change was.
Though it's probably wise not to use this feature gratuitously, it is a much safer bet than leaving some commented out code laying around to eventually be forgotten..
Heckle works by trying to break your code assuming that it will result in failing specs. Although this isn't a new test verification technique, it's definitely an interesting one. The assumption is that if you can mutate parts of your implementation code without creating failure, that code is either doing nothing, or your specs are incomplete.
The
spec command integrates with Heckle when it is installed. It allows you to type in a module name or method name and see if Heckle can break your specs. With this sample run, you can see that I've left some details out of the
Dots::Game specs:
$ spec spec/game_spec.rb -H Dots::Game#start ......... Finished in 0.027817 seconds 9 examples, 0 failures ********************************************************************** *** Dots::Game#start loaded with 2 possible mutations ********************************************************************** 2 mutations remaining... 1 mutations remaining... The following mutations didn't cause test failures: def start @players = interface.get_players @turn = -8 @score = Hash.new(0) rows, cols = interface.get_grid_size @grid = Dots::Grid.new(rows, cols) interface.update_display(self) end
Here's the original code:
def start @players = interface.get_players @turn = 0 @score = Hash.new(0) rows,cols = interface.get_grid_size @grid = Dots::Grid.new(rows,cols) interface.update_display(self) end
What Heckle is telling us is that we never specify that turn must start at 0. Though for the moment this isn't really essential to the way the game operates, the fact that it works with a non-zero initial state was mildly surprising to me. A simple spec is sufficient to get rid of this ambiguity once and for all:
describe "A newly started game" do # ... it "should start at turn 0" do @game.turn.should == 0 end # ... end
Now, whenever we run heckle on
Game#start, it reports back 'no mutants'
$ spec spec/game_spec.rb -H Dots::Game#start .......... Finished in 0.029037 seconds 10 examples, 0 failures ********************************************************************** *** Dots::Game#start loaded with 2 possible mutations ********************************************************************** 2 mutations remaining... 1 mutations remaining... No mutants survived. Cool!
I tend to look at tools like this as a good way to investigate areas that you think might already have some flaws. I wouldn't count on them as a substitute for careful consideration of your spec quality, but they definitely come in handy for shaking things down when it's necessary.
It's worth mentioning that like RCov, Heckle is by no means specific to RSpec. It works just fine with Test::Unit as well. It definitely does come in handy when you're focusing more on interactions however, since it will pick up potential issues with state corruption that might not be exposed until later on down the line when you're using BDD to drive your project.
So far, this entire discussion has been RSpec-centric, and for good reason: If you want to practice BDD in Ruby and are able to start with a fresh canvas, it is very likely that RSpec is the right tool for the job. You've seen in this article that it integrates just as well with tools like RCov and Heckle as Ruby's
Test::Unit does, provides a comprehensive mocking framework, and has tons of room for extensibility.
However, there is a very real issue worth mentioning: Ruby's
Test::Unit is part of the standard distribution, and RSpec is not. This means that there is a ton of test code out there, along with helpers and extensions, that is incompatible with RSpec and would be quite time consuming to rewrite in one fell swoop.
If you're working on a project that needs to maintain
Test::Unit compatibility, but you'd like to introduce the BDD friendly syntax and constructs that you find in RSpec to your test suites, Christian Neukirchen's test/spec is what you're looking for.
In fact, if you take a look at our RSpec code for Dots::Grid, you'll see that only a couple minor changes need to be made to get them running under test/spec.
describe "An empty dots grid" do # all else the same it "should throw an error when connecting non-adjacent dots" do # === RSpec Style === #lambda { @grid.connect([0,0],[0,5]) }.should raise_error(Dots::InvalidEdgeError) # === test/spec style === should.raise(Dots::InvalidEdgeError) { @grid.connect([0,0],[0,5]) } end end describe "A drawn on dots grid" do # all else the same it "should return a set with a box when connect() completes one box" do result = @grid.connect [1,1], [1,0] result.size.should == 1 result.each do |b| # === RSpec Style === #b.should be_an_instance_of(Dots::Box) # === test/spec Style === b.should.be.an.instance_of?(Dots::Box) end end it "should return a set of two boxes when connect() completes two boxes" do @grid.connect [1,0], [2,0] @grid.connect [2,0], [2,1] @grid.connect [2,1], [1,1] result = @grid.connect [1,1], [1,0] result.size.should == 2 result.each do |b| # === RSpec Style === #b.should be_an_instance_of(Dots::Box) # === test/spec Style === b.should.be.an.instance_of?(Dots::Box) end end end
Despite the change in framework, almost all the semantics are preserved. The fundamental difference is that test/spec is implemented on top of Test::Unit, allowing you to mix it in with ordinary TDD code. If you've already created helpers that are based on the
assert_* family of friends, there is nothing to stop you from using them. You can even define contexts side by side with test cases, and use your normal test runners as desired.
Although test/spec does include many of the RSpec niceties, even things like spec docs generation, it is definitely a less all-encompassing tool. You'd have to glue together some of the missing bits, such as a mocking framework, by downloading other packages such as FlexMock or Mocha. Even still, if migrating to RSpec isn't an option, test/spec is about the best compromise that's available in Ruby these days.
I hope that this longish exploration of BDD using Ruby has been helpful to you. Though I think that we've covered enough of the essentials to get you started writing specs and using some helpful tools to make your job easier, you may wish to learn more about the principles behind BDD and the philosophies that go with them. A lot of this background information can be found on behaviour-driven.org, as well as strewn across the blogosphere.
Of course, like any other software development practice, the best way to figure out to what extent these tools and techniques will be useful for you is to hack on some projects and see how they work out. Hopefully you'll find some fun and better code at the other side of the tunnel.
Gregory Brown is a New Haven, CT based Rubyist who spends most of his time on free software projects in Ruby. He is the original author of Ruby Reports.
Return to the Ruby Blog. | http://www.oreillynet.com/lpt/a/7153 | CC-MAIN-2014-41 | refinedweb | 2,045 | 61.56 |
I'm running a software daemon that requires for certain actions to enter a passphrase to unlock some features which looks for example like that:
$ darkcoind masternode start <mypassphrase>
Now I got some security concerns on my headless debian server.
Whenever I search my bash history for example with Ctrl+R I can see this super strong password. Now I imagine my server is compromized and some intruder has shell access and can simply Ctrl+R to find my passphrase in the history.
Ctrl+R
Is there a way to enter the passphrase without it to be shown in bash history, ps, /proc or anywhere else?
ps
/proc
Update 1: Passing no password to the daemon throws an error. This is no option.
Update 2: Don't tell me to delete the software or other helpful hints like hanging the developers. I know this is not a best-practice example but this software is based on bitcoin and all bitcoin based clients are some kind of json rpc server which listens to these commands and its a known security issue still being discussed (a, b, c).
Update 3: The daemon is already started and running with the command
$ darkcoind -daemon
Doing ps shows only the startup command.
$ ps aux | grep darkcoin
user 12337 0.0 0.0 10916 1084 pts/4 S+ 09:19 0:00 grep darkcoin
user 21626 0.6 0.3 1849716 130292 ? SLl May02 6:48 darkcoind -daemon
So passing the commands with the passphrase does not show up in ps or /proc at all.
$ darkcoind masternode start <mypassphrase>
$ ps aux | grep darkcoin
user 12929 0.0 0.0 10916 1088 pts/4 S+ 09:23 0:00 grep darkcoin
user 21626 0.6 0.3 1849716 130292 ? SLl May02 6:49 darkcoind -daemon
This leaves the question where does the history show up? Only in .bash_history?
.bash_history
We're looking for long answers that provide some explanation and context. Don't just give a one-line answer; explain why your answer is right, ideally with citations. Answers that don't include explanations may be removed.
Really, this should be fixed in the application itself. And such applications should be open source, so that fixing the issue in the app itself should be an option. A security related application which makes this kind of mistake might make other mistakes as well, so I wouldn't trust it.
But you were asking for a different way, so here is one:
#define _GNU_SOURCE
#include <dlfcn.h>");
ubp_av[argc - 1] = "secret password";
return next(main, argc, ubp_av, init, fini, rtld_fini, stack_end);
}
Compile this with
gcc -O2 -fPIC -shared -o injectpassword.so injectpassword.c -ldl
then run your process with
LD_PRELOAD=$PWD/injectpassword.so darkcoind masternode start fakepasshrase
The interposer library will run this code before the main function from your application gets executed. It will replace the last command line argument by the actual password in the call to main. The command line as printed in /proc/*/cmdline (and therefore seen by tools such as ps) will still contain the fake argument, though. Obviously you'd have to make the source code and the library you compile from it readable only to yourself, so best operate in a chmod 0700 directory. And since the password isn't part of the command invocation, your bash history is safe as well.
main
/proc/*/cmdline
chmod 0700
If you want to do anything more elaborate, you should keep in mind that __libc_start_main gets executed before the runtime library has been properly initialized. So I'd suggest avoiding any function calls unless they are absolutely essential. If you want to be able to call functions to your heart's content, make sure you do so just before main itself gets invoked, after all initialization is done. For the following example I have to thank Grubermensch who pointed out how to hide a password passed as command line argument which brought getpass to my attention.
__libc_start_main
getpass
#define _GNU_SOURCE
#include <dlfcn.h>
#include <unistd.h>
static int (*real_main) (int, char * *, char * *);
static int my_main(int argc, char * * argv, char * * env) {
char *pass = getpass(argv[argc - 1]);
if (pass == NULL) return 1;
argv[argc - 1] = pass;
return real_main(argc, argv, env);
}");
real_main = main;
return next(my_main, argc, ubp_av, init, fini, rtld_fini, stack_end);
}
This prompts for the password, so you no longer have to keep the interposer library a secret. The placeholder argument is reused as password prompt, so invoke this like
LD_PRELOAD=$PWD/injectpassword.so darkcoind masternode start "Password: "
Another alternative would read the password from a file descriptor (like e.g. gpg --passphrase-fd does), or from x11-ssh-askpass, or whatever.
gpg --passphrase-fd
x11-ssh-askpass
strings
It's not just the history. It is going to show up in ps output as well.
Whoever wrote that piece of software should be hung, drawn and quartered. It is an absolute NO to have to supply a password on the command-line regardless whatever software it is.
For a daemon process it is even MORE unforgivable...
Besides rm -f on the software itself I don't know any solution for this. Honestly: Find other software to get the job done. Don't use such junk.
rm -f
rm
This will clear the ps output.
BE VERY AWARE: This could break the application. You are duly warned that here be dragons.
Now you are duly notified of these dire warnings. This will clear the output displayed in ps. It will not clear your history, nor will it clear the bash job history (such as running the process like myprocess myargs &). But ps will no longer show the arguments.
myprocess myargs &
#!/usr/bin/python
import os, sys
import re
PAGESIZE=4096
if __name__ == "__main__":
if len(sys.argv) < 2:
sys.stderr.write("Must provide a pid\n")
sys.exit(1)
pid = sys.argv[1]
try:
cmdline = open("/proc/{0}/cmdline".format(pid)).read(8192)
## On linux, at least, argv is located in the stack. This is likely o/s
## independent.
## Open the maps file and obtain the stack address.
maps = open("/proc/{0}/maps".format(pid)).read(65536)
m = re.search('([0-9a-f]+)-([0-9a-f]+)\s+rw.+\[stack\]\n', maps)
if not m:
sys.stderr.write("Could not find stack in process\n");
sys.exit(1)
start = int("0x"+m.group(1), 0)
end = int("0x"+m.group(2), 0)
## Open the mem file
mem = open('/proc/{0}/mem'.format(pid), 'r+')
## As the stack grows downwards, start at the end. It is expected
## that the value we are looking for will be at the top of the stack
## somewhere
## Seek to the end of the stack minus a couple of pages.
mem.seek(end-(2*PAGESIZE))
## Read this buffer to the end of the stack
stackportion = mem.read(8192)
## look for a string matching cmdline. This is pretty dangerous.
## HERE BE DRAGONS
m = re.search(cmdline, stackportion)
if not m:
## cause this is an example dont try to search exhaustively, just give up
sys.stderr.write("Could not find command line in the stack. Giving up.")
sys.exit(1)
## Else, we got a hit. Rewind our file descriptor, plus where we found the first argument.
mem.seek(end-(2*PAGESIZE)+m.start())
## Additionally, we'll keep arg0, as thats the program name.
arg0len = len(cmdline.split("\x00")[0]) + 1
mem.seek(arg0len, 1)
## lastly overwrite the remaining region with nulls.
writeover = "\x00" * (len(cmdline)-arg0len)
mem.write(writeover)
## cleanup
mem.close()
except OSError, IOError:
sys.stderr.write("Cannot find pid\n")
sys.exit(1)
Invoke the program by saving it, chmod +x it. Then doing ./whatever <pidoftarget>
If this works, it will produce no output. If it fails, it will complain about something and quit.
chmod +x
./whatever <pidoftarget>
gdb
Can you pass the argument from a file, accessible only by root or the required user?
It's a HUGE no-no to type passwords in the console, but last recourse...begin your line with a space so it doesn't appear in the history.
Maybe this works (?):
darkcoind masternode start `cat password.txt`
darkcoind masternode start `head -1`
password.txt
Unfortunately, if your darkcoind command expects the password as a command-line argument, then it will be exposed through utilities such as ps. The only real solution is to educate the developers.
darkcoind
While the ps exposure might be unavoidable, you could at least keep the password from being written out in the shell history file.
$ xargs darkcoind masternode start
CtrlD
$ xargs darkcoind masternode start
CtrlD
The history file should only record xargs darkcoind masternode start, not the password.
xargs darkcoind masternode start
ignorespace
$HISTCONTROL
You can keep the password out of your shell's history by executing the command from a new shell process, which you then immediately terminate. For example:
bash$ sh
sh$ darkcoind masternode start 'correct horse battery staple'
sh$ exit
bash$
Make sure sh is configured not to save its history in a file.
sh
Of course this doesn't address the other problems, such as the password being visible in ps. There are, I believe, ways for the darkcoind program itself to hide the information from ps, but that only shortens the window of vulnerability.
As others have stated, look into your shell history control for hiding the information from history.
But one thing nobody seems to have suggested yet is to mount /proc with the hidepid parameter. Try modifying your /proc line in /etc/fstab to include hidepid, like this:
hidepid
/etc/fstab
# <file system> <mount point> <type> <options> <dump> <pass>
proc /proc proc defaults,hidepid=2 0 0
For Bitcoin, the official developer answer is to use the provided python wrapper in contrib/bitrpc/bitrpc.py (github):
contrib/bitrpc/bitrpc.py
It asks for a password in a secure way if you use the command walletpassphrase, for example. There are no plans to add interactive functionality to bitcoin-cli.
It asks for a password in a secure way if you use the command walletpassphrase, for example. There are no plans to add interactive functionality to bitcoin-cli.
walletpassphrase
bitcoin-cli
and:
bitcoin-cli will remain as-is and not gain interactive functionality.
bitcoin-cli will remain as-is and not gain interactive functionality.
Source: #2318
Unlock wallet:
$ python bitrpc.py walletpassphrase
Change passphrase:
$ python bitrpc.py walletpassphrasechange
For darkcoin it works anlogue:
By posting your answer, you agree to the privacy policy and terms of service.
asked
1 year ago
viewed
8050 times
active
4 months ago | http://serverfault.com/questions/592744/how-to-hide-a-password-passed-as-command-line-argument/592755 | CC-MAIN-2015-22 | refinedweb | 1,753 | 66.44 |
Main class of the Observability Analysis plug-in. More...
#include <Observability.hpp>
Main class of the Observability Analysis plug-in.
Definition at line 54 of file Observability.hpp.
Implement this to tell the main Stellarium GUI that there is a GUI element to configure this plugin.
Reimplemented from StelModule.
Execute all the drawing functions for this module.
Reimplemented from StelModule.
Display acronychal and cosmical rising/setting.
Display date of the full moon.
Has any effect only if the Moon is selected.
Display nights when the object is above the horizon after darkness.
Display when selected object is in opposition.
Display today's events (rise, set and transit times).
Return the value defining the order of call for the given action For example if stars.callOrder[ActionDraw] == 10 and constellation.callOrder[ActionDraw] == 11, the stars module will be drawn before the constellations.
Reimplemented from StelModule.
get the current font color:
get current font size:
Get the user-defined altitude of the visual horizon.
get Show Flags from current configuration:
Get the user-defined Sun altitude at twilight.
Initialize itself.
If the initialization takes significant time, the progress should be displayed on the loading bar.
Implements StelModule.
Read (or re-read) settings from the main config file.
Default values are provided for all settings. Called in init() and resetConfiguration().
Restore and reload the default plug-in settings.
Save the plug-in's configuration to the main configuration file.
Set the color of the font used to display the report.
Applies only to what is drawn on the viewport.
Set the size of the font used to display the report.
Applies only to what is drawn on the viewport.
Set the angular altitude of the visual horizon.
Set the angular altitude below the horizon of the Sun at twilight.
This determines the boundaries of day/night for observation purposes.
invertedAppearanceproperty of QSlider.
Controls whether an observability report will be displayed.
Update the module with respect to the time.
Implements StelModule.
Definition at line 66 of file Observability.hpp. | http://stellarium.org/doc/0.15/classObservability.html | CC-MAIN-2017-51 | refinedweb | 335 | 54.08 |
From: Beman Dawes (bdawes_at_[hidden])
Date: 2006-06-08 12:51:09
Gennaro Prota wrote:
> On Sun, 04 Jun 2006 16:34:38 -0400, Beman Dawes <bdawes_at_[hidden]>
> wrote:
>
>> A refresh of the .zip file for the Endian library, based on comments
>> received so far, is available at
>>
>>
>> The docs are online at
>>
>>
>
> Hi Beman,
>
> I had a quick look and hope to do a more careful analysis in the next
> days. Nonetheless I have some not very useful comments:
>
> * as far as I know (I have been absent from the list for long time, so
> please correct me if this has changed again) the license reference
> text we use now doesn't contain "use, modification, and distribution",
> despite what says. The adopted
> version is the one reported at
>
Fixed. lib_guide.htm corrected, too.
> * there is no guarantee that an unsigned char has 8 bits...
The C and C++ standards specify char, signed char, and unsigned char all
have exactly 8 bits, AFAIK.
> * I fear I'm missing something but does unrolled_byte_loops really
> "unroll" loops at compile time? It seems to me it just uses (run-time)
> recursion.
The depth of recursion is controlled at compile time. The runtime calls
are presumably optimized away by inlining. You would have to look at the
generated code and/or run some tests to see if there is any abstraction
penalty.
In any case, that is an implementation detail, as indicated by being in
namespace detail. It can be replaced with something else if need be.
> * integer_cover_operators initial section reports
> "integer_operations.hpp", presumably as filename,
Fixed.
> and seem to have
> many superfluous includes.
Fixed.
> The guard macro name also seems
> inconsistent.
Fixed.
> More importantly, is it intentional that stream input
> and output only consider ostream and istream (no wide versions, no
> templates, etc.)?
Yep, that needs to be fixed. I suspect the current version reflects
compiler problems cica 1999. I've added a "TODO" comment to the code in
case so it won't be forgotten in case I don't get to it right away.
> * (minor) the example omits fclose()
It was omitted for brevity. I've now added it.
> * though the Wikipedia article seems to be, at the time I'm writing,
> in a decent state, it might easily degrade in the future (I've
> experience this myself; no ranting :)); OTOH we can't include it into
> the boost files, due to the Wikipedia license. It might be worth
> writing something ourselves, at least in the long run, or link to a
> specific version of it, with a word of caution that any newer versions
> have not been verified by the boost members.
Yes, reference to the Wikipedia in docs is something we need to discuss.
The articles are often extremely well written and authoritative, and it
save a lot of work (and then later maintenance) to link to them. But as
you say, we have no way to know if an article might degrade in the future.
My current feeling is that the advantages of linking to a well-written
Wikipedia entry outweigh the disadvantages, but it is an open question
that other Boosters need to think about.
Thanks for the comments and corrections!
--Beman
Boost list run by bdawes at acm.org, gregod at cs.rpi.edu, cpdaniel at pacbell.net, john at johnmaddock.co.uk | http://lists.boost.org/Archives/boost/2006/06/106024.php | CC-MAIN-2016-30 | refinedweb | 557 | 73.07 |
Manage repository webhooks via the web interfaceEstimated reading time: 2 minutes
Prerequisites
- You must have admin privileges to the repository in order to create a webhook.
- See Webhook types for a list of events you can trigger notifications for using the web interface.
Create a webhook for your repository
In your browser, navigate to
https://<dtr-url>and log in with your credentials.
Select Repositories from the left navigation pane, and then click on the name of the repository that you want to view. Note that you will have to click on the repository name following the
/after the specific namespace for your repository.
Select the Webhooks tab, and click New Webhook.
- From the drop-down list, select the event that will trigger the webhook.
Set the URL which will receive the JSON payload. Click Test next to the Webhook URL field, so that you can validate that the integration is working. At your specified URL, you should receive a JSON payload for your chosen event type notification.
{ "type": "TAG_PUSH", "createdAt": "2019-05-15T19:39:40.607337713Z", "contents": { "namespace": "foo", "repository": "bar", "tag": "latest", "digest": "sha256:b5bb9d8014a0f9b1d61e21e796d78dccdf1352f23cd32812f4850b878ae4944c", "imageName": "foo/bar:latest", "os": "linux", "architecture": "amd64", "author": "", "pushedAt": "2015-01-02T15:04:05Z" }, "location": "/repositories/foo/bar/tags/latest" }
Expand “Show advanced settings” to paste the TLS certificate associated with your webhook URL. For testing purposes, you can test over HTTP instead of HTTPS.
Click Create to save. Once saved, your webhook is active and starts sending POST notifications whenever your chosen event type is triggered.
As a repository admin, you can add or delete a webhook at any point. Additionally, you can create, view, and delete webhooks for your organization or trusted registry using the API. | https://docs.docker.com/ee/dtr/admin/manage-webhooks/use-the-web-ui/ | CC-MAIN-2019-26 | refinedweb | 286 | 55.64 |
Hi everyone,
I am working with a presentation were I have an iPhone and in the phone I have a seperate .png image that
represant a twitter feed etc. I want the feed to scroll behind and not shown out-side the phone. I've seen a
video and what he does is enable the "allow objects on slide to layer with master" but nothing happens for me.
I would really appriciate if you can help/ post a step by step how to do it. Obviously I am missing something.
Thanks,
Alex
you will need to create an alpha graphic of the image:
Import the iPhone image into an image editing application (Photoshop/Paintshop)
use a selection tool to select where the phones screen is
delete
delete all of the detail surrounding what is outside the phones black frame using the erasor tool
save as a tiff
import into Keynote and images placed behind the phone will show
Retrieving data ... | https://discussions.apple.com/thread/4894474?tstart=0 | CC-MAIN-2014-23 | refinedweb | 160 | 65.66 |
Recently I came across this code fragment:
// look for element which is the smallest max element from
// a given iterator
int diff = std::numeric_limits<int>::max();
auto it = nums.rbegin();
auto the_one = nums.rbegin();
for (; it != given; ++it) // this terminates
{
int local_diff = *it - *given;
// if the element is less than/equal to given we are not interested
if (local_diff <= 0)
continue;
if (local_diff < diff)
{
// this update the global diff
diff = local_diff;
the_one = it;
}
}
std::max_element
auto the_one = std::min_element(nums.rbegin(), given, [given](int a, int b) { bool good_a = a > *given; bool good_b = b > *given; return (good_a && good_b) ? a < b : good_a; });
The trick is to write a comparison function that declares any "good" element (one that's greater than
*given) to compare smaller than any "not good" element. Two "good" elements are compared normally; two "bad" elements are always declared equivalent. | https://codedump.io/share/6RHLRD3ijvCj/1/stl-algorithm-for-smallest-max-element-than-a-given-value | CC-MAIN-2017-13 | refinedweb | 141 | 52.8 |
Does Neutron network node have fip namespace?
Hello,
I have 4 node Kilo installation with DVR and OVS. When I assign floating IP to VMs, fip namespace gets created on the compute host where VM is hosted. This consistently happens on all compute nodes as expected, except to the one with neutron server (network node). That host does have snat namespace, but not fip namespace. Is this expected?
The reason I am interested is that VMs hosted in the network node do not have working floating IP. VM successfully gets FIP assigned, but the VM is not reachable (ping, ssh) via floating IP. I do have security group rules setup properly. VMs on other nodes with the same security group are ping/ssh'able. I'd like to know if absence of fip namespace on the networking node is a root cause, or is it expected networking node to have only snat namespace, but not fip namespace.
Thanks,
Nodir | https://ask.openstack.org/en/question/79795/does-neutron-network-node-have-fip-namespace/?sort=votes | CC-MAIN-2019-30 | refinedweb | 159 | 73.98 |
I am trying to use python to help me crack Vigenère ciphers. I am fairly new to programming but I've managed to make an algorithm to analyse bigram frequencies in a string of text. This is what I have so far:
import nltk, string
from nltk import bigrams
Ciphertext = str(input("What is the text to be analysed?"))
#Removes spacing and punctuation to make the text easier to analyse
def Remove_Formatting(str):
str = str.upper()
str = str.strip()
str = str.replace(' ','')
str = str.translate(str.maketrans({a:None for a in string.punctuation}))
return str
Ciphertext = Remove_Formatting(Ciphertext)
#Score is meant to increase if most common bigrams are in the text
def Bigram(str):
Common_Bigrams = ['TH', 'EN', 'NG',
'HE', 'AT', 'AL',
'IN', 'ED', 'IT',
'ER', 'ND', 'AS',
'AN', 'TO', 'IS',
'RE', 'OR', 'HA',
'ES', 'EA', 'ET',
'ON', 'TI', 'SE',
'ST', 'AR', 'OU',
'NT', 'TE', 'OF']
Bigram_score = int(0)
for bigram in str:
if bigram in Common_Bigrams:
Bigram_score += 1
return Bigram_score
Bigram(Ciphertext)
print (Bigram_score)
Traceback (most recent call last):
File "C:/Users/Tony/Desktop/Bigrams.py", line 36, in <module>
print (Bigram_score)
NameError: name 'Bigram_score' is not defined
You could make Bigram_score global, like this:
def Bigram(string): # don't override str global Bigram_score Common_Bigrams = ['TH', 'EN', 'NG', 'HE', 'AT', 'AL', 'IN', 'ED', 'IT', 'ER', 'ND', 'AS', 'AN', 'TO', 'IS', 'RE', 'OR', 'HA', 'ES', 'EA', 'ET', 'ON', 'TI', 'SE', 'ST', 'AR', 'OU', 'NT', 'TE', 'OF'] Bigram_score = 0 # that 0 is an integer is implicitly understood for bigram in string: if bigram in Common_Bigrams: Bigram_score += 1 return Bigram_score
You could also bind the returned result from the
Bigram function to a variable, like this:
Bigram_score = Bigram(Ciphertext) print(Bigram_score)
or:
print(Bigram(Ciphertext))
When you assign values to variables in a function, they are local and bound to that function. If a function returns anything, the returned value must be bound to a variable to be reused properly (or used directly).
This is an example of how it works:
spam = "spam" # global spam variable def change_spam(): spam = "ham" # setting the local spam variable return spam change_spam() print(spam) # prints spam spam = change_spam() # here we assign the returned value to global spam print(spam) # prints ham
In addition, your for loop loops over unigrams instead of bigrams. Let us take a closer look:
for x in "hellothere": print(x)
This will print unigrams. We therefore rename the
bigram variable in your code to see where there are some logical problems.
for unigram in string: if unigram in Common_Bigrams: print("bigram hit!")
Since there are no unigrams that are identical with any bigrams,
"bigram hit!" will never be printed. We could try to get bigrams with a different approach, using a while loop and an index number.
index = 0 n = 2 # for bigrams while index < len(string)-(n-1): # minus the length of n-1 (n-grams) ngram = string[index:index+n] # collect ngram index += 1 # important to add this, otherwise the loop is eternal! print(ngram)
Next, just include in the loop what you want to do with the bigram. | https://codedump.io/share/RzaoVRXRngh1/1/using-python-to-analyse-bigrams-in-a-string-of-text | CC-MAIN-2017-13 | refinedweb | 509 | 56.18 |
I had a great time at my talk PDC2009 talk, but i was disappointed that I could not demo in both C# and VB… So here is the next best thing: A full play-by-play of the demo, but all in VB! Enjoy.
What you need to get started:
I am starting off with the new Business Application Template that gets installed with RIA Services.
This new template includes:
For this demo, I am going to used a customized version of the template..
After you create the project, you see we have a simple solution setup that follows the “RIA Application” pattern. That is one application that happens to span a client (Silverlight) and server (asp.net) tiers. These two are tied such that any change in the Silverlight client is reflected in the server project (a new XAP is placed in client bin) and appropriate changes in the server result in new functionality being exposed to the Silverlight client. To parts of the same application.
I started out with an Entity Framework model. RIA Services supports any DAL including Linq2Sql, NHibernate as well as DataSets and DataReader\Writer. But EF has made some great improvements in .NET 4, so I felt it was a good place to start.
So here is the EF model I created. Basically we have a set of restaurants, each of which has a set of plates they serve. A very simple model designed many to show off the concepts.
Then we need to place to write our business logic that controls how the Silverlight client can interact with this data. To do this create a new DomainService.
Then select the tables you want to expose:
Now, let’s look at our code for the DomainService…
In line 10 – we are enabling this service to be accessed from clients.. without this, the DomainService is only accessible from on the machine (for example for an ASP.NET hosted on the same machine).
In line 11: we are defining the DomainService – you should think of a DomainService as just a special kind of WCF Service.. one that is higher level and has all the right defaults set so that there is zero configuration needed. Of course the good news is that if you *need* to you can get access to the full richness of WCF and configure the services however you’d like.
In line 12: you see we are using the LinqToEntitiesDomainService. RIA Services supports any DAL including LinqToSql or NHibernate. Or what I think is very common is just POCO.. that is deriving from DomainService directly. See examples of these here…
In line 14: We are defining a Query method.. this is based on LINQ support added in VS2008. Here we define the business logic involved in return data to the client. When the framework calls this method, it will compose a LINQ query including paging, sorting, filtering from the client then execute it directly against the EF model which translate it into optimized TSQL code. So no big chunks of unused data are brought to the mid-tier or the client.
Now let’s switch over the client project and look at how we consume this.
in Views\Home.xaml we have a very simple page with just a DataGrid defined.
now let’s flip over to codebhind..
Notice we have a MyApp.Web namespace available on the client. Notice that is the same namespace we defined our DomainService in..
So, let’s create a local context for accessing our DomainService. First thing you will notice is that VS2010 Intellisense makes it very easy to find what we want.. it now matches on any part of the class name.. So just typing “domainc” narrows our options to the right one..
In line 2, notice there is a property on context called Restaurants. How did we get that there? Well, there is a query method defined on the DomainService returning a type of type Restaurant. This gives us a very clean way to do databinding. Notice this call is actually happening async, but we don’t have to deal with any of that complexity. No event handlers, callbacks, etc.
In line 4, while the whole point of RIA Services is to make n-tier development as easy as two-tier development that most of us are used to, we want to make sure the applications that are created are well behaved. So part of this is we want to be explicit when a network call is being made.. this is not transparent remoting. Network calls must be explicit. In this line we are mentioning which query method to use as you might define more than one for the same type with different logic.
Now we run it..
This is very cool and simple. But in a real world case, i am guessing you have more than 20 records… sometimes you might have 100s, or thousands or more. You can’t just send all those back to the client. Let’s see how you can implement paging and look at some of the new design time features in VS2010 as well.
Let’s delete that code we just wrote and flip over to the design surface and delete that datagrid.
Drop down the DataSources window (you may need to look under the Data menu for “Show Data Sources”
If you are familiar with WinForms or WPF development, this will look at least somewhat familiar to you. Notice our DishViewDomainContext is listed there with a table called Restaurant. Notice this is exactly what we saw in the code above because this window is driven off that same DomainContext.
Dropping down the options on Restaurant, we see we have a number of options for different controls that can be used to view this data… of course this is extensible and we expect 3rd party as well as your custom controls to work here. Next see the query method here that is checked. That lists all the available options for query methods that return Restaurant.
Now if we expand the view on Restaurant, we see all the data member we have exposed. This view gives us a chance to change how each data member will be rendered. Notice I have turned off the ID and changed the Imagepath to an Image control. Again this is an extensible and we expect 3rd party controls to plug in here nicely.
Now, drag and drop Restaurant onto the form and we get some UI
And for you Xaml heads that want to know what really happens… Two things. First if the DomainDataSource is not already created, one is created for you.
Finally, the DataGrid is created with a set of columns.
Then setup a grid cell by click 4/5ths of the way down on the left grid adorner. Then select the grid, right click, select reset layout all.
.. add poof! VS automatically lays out the DataGrid to fill the cell just right.
Now, personally, I always like the Name column to come first. Let’s go fix that by using the DataGrid column designer. Right click on the DataGrid select properties then click on the Columns property..
In this designer you can control the order of columns and the layout, etc. I moved the image and name fields to the top.
Now, let’s add a DataPager such that we only download a manageable number of records at a time. From the toolbox, simply drag the datapager out.
We use our same trick to have VS auto layout the control Right click on it and select Reset Layout\All.
That is cool, but there is a big gap between the DataGrid and the DataPager.. I really want them to be right. This is easy to fix. Right click on the grid adorner and select “Auto”..
Perfect!
Now, we just need to wire this up to the same DataSource our DataGrid is using “connect-the-dots” databinding. Simply drag the Restaurant from the DataSources window on top of the DataGrid.
For you Xaml heads, you’ll be interested in the Xaml this creates..
Notice, we don’t need to create a new DomainDataSource here… we will use the one that is already on the page.
Now, we are doing an async call.. so let’s drag a BusyIndicator from the new Silverlight 4 Toolkit.
We need to write up the IsBusy to the restaurantDomainDataSource.DomainContext.IsLoading… Luckily there is some nice databinding helper in VS2010. Select properties, then IsBusy, then DataBinding.
Again, for you Xaml heads, the Xaml that gets generated is pretty much what you’d expect.
and once it is loaded…
Very cool… that was a very easy was to get your data. Page through it and notice that with each page we are going back all the way to the data tier to load more data. So you could just as easily do this on a dataset of million+ records. But what is more, is that sorting works as well and just as you’d expect. It doesn’t sort just the local data, it sorts the full dataset and it does it all way back onto the data tier and just pulls forward the page of data you need to display.
But our pictures are not showing up… let’s look at how we wire up the pictures. The reason they are not showing up is that our database returns just the simple name of the image, not the full path. This allows us to be flexible about the where the images are stored. The standard way to handle this is to write a value converter. Here is a simple example:
Now, let’s look at how we wire this converter to the UI. First, let’s use the Document Outline to drill through the visual tree to find the Image control.
Then we select the properties on the image and wire up this converter. If you have done this in Xaml directly before, you know it is hard to get right. VS2010 makes this very easy!
Oh, and for you Xaml heads… here is what VS created..
and
Now let’s look at how we drill down and get the details associated with each of these records. I want to show this is a “web” way… So I’ll show how to create a deep link to a new page that will list just the plates for the restaurant you select.
First we add a bit of Xaml to add the link to the datagrid..
And to implement the button click handler…
Here we are getting the currently selected Restaurant, then we cons up a new URL to the page “Plates”. We pass a query string parameter of restaurantId…
Now, let’s build out the Plates page that will the list of Plates for this restaurant. First let’s great a a Plates page. Let’s add a new Plates under the Views directory.
Now we need to define a query to return the Plates. Notice that only the data you select is exposed. So we get to go back to the server, to our DishViewDomainService and add a new query method.
Now we go back to the client, and see your DataSources window now offers a new datasource: Plates.
Now, just as we saw above, I will drag and drop that data source onto the form and i get a nice datagrid alreayd wired up to a DomainDataSource.
Then, with a little formatting exactly as we saw above, we end up with…
And when we run it… First, you see the link we added to the list of Restaurants..
Clicking on anyone of them navigates us to our Plates page we just built.
This is cool, but notice we are actually returning *all* the plates, not just the plates from the restaurant selected. To address this first we need modify our GetPlates() query method to take in a resource id.
Now, back on the client, we just need to pass the query string param…
Now, we run it and we get the just the plates for the restaurant we selected.
what’s more is we now have a deep link such that it works when I email, IM or tweet this link to my buddy who happens to run a different browser ;-)
Ok… now for a details view… Let’s do a bit more layout in the Plates.xaml. First, let’s split the form in half vertically to give us some cells to work in.
In the bottom left we will put the details view to allow us to edit this plate data. Let’s go back to the DataSources window and change the UI type to Details.
Dragging that Details onto the form… we get some great UI generation that we can go in and customize.
In particular, let’s format that Price textbox as a “currency”… using the new String Formatting support in Silverlight 4.
And again, for you Xaml heads… this created:
Now, let’s add an image to the other side. Simply drop an Image control on the form and select Reset Layout\All
Now we can easily change the image to be “Uniform”
Now we need to write up the binding here so that as selection changes, this image is update. Luckily, that is very easy to do. Simply drag and drop from the Data Sources window…
Then we need to wire up our converter just as we saw before..
Run it…
That looks great!
But when we try edit something, we get this error..
Ahh, that is a good point, we need to go back and explicitly define a Update method to our DomainService on the server.
In line 2, notice we take the NumberUpdates and increment by one. it is nice that we send the entry entity back and forth, so we can do entity level operations very easily.
Next in line 3, we pull out the original value.. .this is the plate instance as the client saw it before it was updated.
In line 4-7, we first check to see if the price has changed, if it has, we add a fee of one dollar for a price change.
Finally in line 8-9, we submit this change to the database.
Now we just need to drop a button on the form.
Then write some codebehind..
What this is going to do is find all the entities that are dirty (that have changes) and package them up and send them to the server.
Now notice if you make a change price to the data and hit submit the NumberUpdates goes up by one and the the price has the one dollar fee added.
Then submit.. NumberUpdates is now 63 and the price is $73.84..
Then if you set a breakpoint on the server, change two or three records on the client. Notice the breakpoint gets hit for each change. We are batching these changes to make an efficient communication pattern.
Great.. now let’s look at data validation.
We get some validation for free. for example Calorie Count is a int, if we put a string in, we get a stock error message.
If we want to customize this a bit more, we can go back to the server and specify our validation there. It is important to do it on the server because you want validation to happen on the client for good UI, but on the server for the tightest security. Following the DRY principle (Don’t Repeat Yourself) we have a single place to put this validation data that works on the client and the server.
The data validation attributes are a core part of .NET with ASP.NET Dynamic Data and ASP.NET MVC using the exact same model.
But what if they are not expressive enough for you? For example, say I have a custom validation I have for making sure the description is valid.. To do that, I can write some .NET code that executes on the server AND the client. Let’s see how to do that. First I create a class on the server..
Notice the name here PlateValidationRules.shared.cs…. the “.shared” part is important… it is what tells us that this code is meant to be on the client and the server.
In this case, i am saying a valid description is one that has 5 more more words
Then to wire this up to the description property…
Then running the app, we see all our validations…
Lots of times in business applications we are dealing with valuable data that we need to make sure the user is authentication before we return in. Luckily this is very easy to do with RIA Services. Let’s go back to our DomainServices on the server and add the RequiresAuthentication attribute.
Then when you run the application..
So let’s log in… I don’t have an account created yet, luckily the Business Application Template supports new user registration. All this is based on ASP.NET Authentication system that has been around sense ASP.NET 2.0.
Here we are creating a new user…
And now we get our data…
Now, that we have a user concept.. why don’t we add one more setting to let the user customize this page. So we edit the web.config file to add a BackgroundColor.
And we go into the User.cs class on the server and add our BackgroundColor.
Now, back on the client, let’s build out UI using the DataSources window just as we have seen above. But this time, I have created a very simple ColorPicker control in order to show that it is possible to use your own custom control.
Drag and drop that onto the form..
Then change the binding to be TwoWay using the databinding picker.
Then I think we need a nice header here with the User name in it. To so that, let’s add a TextBlock, set the fontsize to be big. Then do connect the dots databinding to write up to the user name.
Then let’s use the string format databinding to customize this a bit..
Next we put a Submit button.
Now when we run it… we can modify the user settings.
The really cool part is that if the user goes to another machine and logs in, they get the exact same experience.
Wow, we have seen a lot here.. We walked through end-to-end how to build a Business Application in Silverlight with .NET RIA Services. We saw the query support, validating update, authorization and personalization as well as all the great new support in VS2010. Enjoy! | http://blogs.msdn.com/b/brada/archive/2009/11/27/pdc09-talk-building-amazing-business-applications-with-silverlight-4-ria-services-and-visual-studio-2010-now-in-visual-basic.aspx?Redirected=true | CC-MAIN-2015-27 | refinedweb | 3,124 | 81.43 |
(list(list(str))) must be a sequence of tokens.
y (list(list(list(str))) important).
Examples
from ignite.metrics import Rouge m = Rouge(variants=["L", 2], multiref="best") candidate = "the cat is not there".split() references = [ "the cat is on the mat".split(), "there is a cat on the mat".split() ] m.update(([candidate], [references])) print(m.compute())
{'Rouge-L-P': 0.6, 'Rouge-L-R': 0.5, 'Rouge-L-F': 0.5, 'Rouge-2-P': 0.5, 'Rouge-2-R': 0.4, 'Rouge-2-F': 0.4}
New in version 0.4.5.
Changed in version 0.4.7:
updatemethod has changed and now works on batch of inputs.
- | https://pytorch.org/ignite/v0.4.8/generated/ignite.metrics.Rouge.html | CC-MAIN-2022-27 | refinedweb | 110 | 75.37 |
[Date Index]
[Thread Index]
[Author Index]
Many keys not working under Linux Mandrake 10.1
Hi all,
I just installed Mathematica 5.01 under Linux Mandrake 10.1, and many
keys are not working in the graphical interface: cursors (beep), delete
(square drawn), back (square drawn), shift+return (just a return), etc.
Additinally, I cannot select the text with the mouse. All this makes the
graphical interface essentially unusable.
I don't know if this may have something to do with the fact that
Mandrake 10.1 uses unicode as default.
I have looked at the Mathematica FAQ and searched this group and the web
with google, without any result.
Any idea?
Many thanks in advance,
Daniel Arteaga | http://forums.wolfram.com/mathgroup/archive/2004/Dec/msg00369.html | CC-MAIN-2015-06 | refinedweb | 118 | 68.57 |
Gesturn Serial 🚨
Gesturn Serial
Pax Soft de muestreo de frente que a primera vista no podrás reafirmar su paga. Pablo escribió: Nota . Desde antes de la instalación del servidor, es de matriz 3.0, y ya todo funciona normal.
Instala Y no Instala. Instala nuevamente el Kernel, es el mismo kernel que en Beta . Ubuntu 11.04 – softbuilder.ptwiki.org .
A detailed comparison of Microsoft PowerPoint vs. PowerPoint 2007Â . it does not explain the detailed interface. [ By: Mike Brown ]Â .
Pact A contract is an agreement that establishes the relationship between the agent, the buyer and seller.. there are many different kinds of contracts such as employment contracts, rental contract, lease, credit card contract, and many others.
Total learning courses in 200-500 pages (Instructor’s Manual included) in PDF format. Full text searchable. After you enroll and complete the course, you will get a discount on any book you purchase within.
Con una sola llave, la lectora de digital, graba de serie o graba de la pelógrafica digital y amigable, etc. Un programa de gesto X funciona como un controlador.
Extremely Fast and Precise Visual Data Recovery. De “BS” quiere decir “Benefitsoft”. Benefitsoft v5 is an absolute Data recovery software which provides easy-to-use graphical interface and.
L’homme est menu par RAS évidemment. Unineste, GES, harddisk, gesturn, ePhipps .
A full system scan can also be used to diagnose hardware issues with your system. Use Mdrbtux to monitor and troubleshoot hardware performance issues at the system level.
Facebook 2011 serial key reddit UPDATE – 10/31/2013Â . The mass-produced version of the popular streaming game.
Critical Errors The following is a list of the CWE-103, CWE-297, CWE-330, and CWE-355. only possible way to prevent the use of such libraries is to properly check the input parameters to the functions that use them. 1. I stumbled upon recently a similar
· MMORPG-RPG-MMORPG-MMORPG Roms and maps for sms gobi and tmb. gesturn serial Crack Mac.  .
You can also find a [crack only] full cracked Gesturn Serial Crack Free download. Using the following crack will allow you to activate gesturn serial quickly and easily with an simple key. .
. Vb Serial Number Without Any Software To Crack Mode.Q:
Set a pull request description in Github
I’m reviewing the Pull Requests and I would like to set the description for all of them before accepting them.
Is it possible to set a description for them by default in the pull request?
A:
There is a config option for this.
In the config file you find the setting hidden from public view.
It’s easy to add a setting like this to your.git/config:
[branch “master”] remote = origin
merge = refs/heads/master
merge = refs/heads/master
merge = refs/heads/master
merge = refs/heads/master
The last line will add the description on every pull request.
Q:
Nested FOR loops, merge/combine results
I have two lists, from two separate loops. The first list has 3 items with a 0 value. The second list has 2 items with a 1 value. I want to be able to loop through both lists and combine the values so that I get one list with 3 items.
List 1
0 0
0 0
1 1
List 2
1 0
0 0
Output
0 0
1 1
The first element in the result has to be the maximum of 0 and 1.
I am not sure how I would code the a nested for loop to do this.
I have tried following, but to no avail.
var myList = db.Test.GroupBy(x => x.List1).Select(group => group.Max());
var test = group.Select(x => x.List2).Max();
myList.AddRange(test);
A:
It appears as if you are looking to pull out all the pairs that meet a certain criteria for a given criteria. I would do it like this:
using System;
using
0cc13bf012
Save time, save money, and share the joy with more of your friends. Go ahead and share this with your friends on Facebook, Twitter, or email.
That’s all it takes. If you’ve learned one thing from this video, let it be this. Be excellent to each other.To all those who have asked about my plans to run for public office, the answer is a resounding yes!
For nearly a decade, I have been one of the top five most visible elected officials in Metropolitan Nashville.
I am proud of what we have accomplished during my time in the Tennessee General Assembly (the past 12 years) and in city government (9 years).
I have received several awards recognizing my dedication to the people of Nashville and Metro government.
In my current role as Vice Mayor of Nashville, I have had the opportunity to serve the people of the vibrant Nashville area.
I am deeply passionate about Nashville and the issues facing our great city. We will continue to build upon the incredible strides made under Mayor Barry and have ambitious plans to turn Nashville into a great place to live, raise a family and work, where our youth can aspire to something greater.
To all of you who have supported me with your votes, phone calls and encouragement over the years, I promise that if elected your voice will be heard. I will fight for you every day.The present invention relates generally to the field of osmosis and, more particularly, to a solution for the separation of H.sub.2 O from oxygen and carbon dioxide.
Osmosis has been widely used to provide an inexpensive, safe, and simple means of producing purified water. However, it is difficult to provide a device capable of providing essentially pure water under pressure.
Traditional methods for producing purified water from tap water use membranes to separate out the low pressure components of tap water, such as H.sub.2 O. However, such membranes can produce a solution of only a low solute concentration. A high solute concentration is desirable in purified water production.
Accordingly, there is a need for an apparatus which can produce essentially pure water with high solute concentration, but which is capable of being operated under pressure without requiring the production of exotic membranes or the use of special designs. In the present study, we noted a less than 10% reduction in the OS of patients with CHD who received high-dose statin treatment (rosuvastatin) compared to those without stat
A:
I had the same issue as you, i researched a lot and finally i found the solution
First of all, when you open this file then you can see “PK” there
“PK……..” is the key of your Serial number
But i couldn’t understand what is “EXE.LTM” in the file, i searched a lot for that and i found that it is a exe file that is the updated version of the serial number, you can get this file from
So i just copied this file from
In my case the serial number was 1.0.9.0
So i replaced the “1.0.9.0” with my serial number “1.8.2.0” from there “PK” and i copied the EXE.LTM file and renamed it as “1.0.9.0.exe.ltm” and it worked and don’t need to change serial number again
I hope this helps you
Perfect Strangers
Perfect Strangers is an American sitcom that ran from September 24, 1990 to February 4, 1994. Created by Candice Rialson, and produced by Castle Rock Entertainment, the series stars Mark Linn-Baker and Valarie Pettiford as a married couple whose relationship is tested by the constant communication that occurs between them. The show is a spinoff of the ABC sitcom Fish, and is a first-season production of the Fox Broadcasting Company. It originally aired on the Fox network in the United States.
Premise
Mark and Vanessa Wainwright are married couple. They live in their home, where their constant communication is a source of tension. Mark receives a message from a mysterious woman who calls herself Vera, and discovers she actually is his long-lost sister.
The Wainworthys visit Vera, who has moved in with her estranged daughter. Mark soon learns that Vera is in dire financial straits; he considers buying her a house and helping her to get back on her feet, but the Wainworthys have other ideas. Mark has trouble keeping their relationship under wraps, while a budding romance between Vanessa and their neighbor’s son further complicates things. After Mark initially rejects the | https://setewindowblinds.com/gesturn-serial/ | CC-MAIN-2022-40 | refinedweb | 1,429 | 64.41 |
CodePlexProject Hosting for Open Source Software
Whenever I run my orchard project from VS2010 it fails and says type or namespace contrib could not be found (this is for the keepalive module). This used to work fine. If I take out the entire containing folder of this module, I get the same problem but
with another random module (yes, I tested).
Why does this happen and how can I fix it?
Does it build from VS?
Nope, fails with the same message/error.
You are using the full source code, right?
Well, I opened the website in VS2010 (installed Orchard via web pi). I didn't get the source from here.
That's why. If you want to be able to compile from visual studio, you need the full source code.
Ok, I downloaded the src and opened the .sln (inside src folder). Is this really the way to go to be able to edit the project from VS2010? I will always need to edit the project from VS2010 as this is how I will make new designs with css etc. Is there not
a less complex way?
This solution has like 50 projects, isn't this overkill just for me to do some minor changes? Alternatively, is there a way for me to create new themes and css without VS2010?
Thanks
You can create themes and modules without VS, yes, but if you are using VS, the full source is the friendliest environment. If you do not want to use the full source code, just remember to never attempt to build from VS and instead let the application do
its dynamic compilation thing. VS then acts as a glorified text editor, but you won't get much IntelliSense, you won't be able to debug most of the code, etc.
Hi,
I get you, I made my own theme outside of vs2010, I didn't really think earlier.
Quick question, while I am here: I want to add a background image to the theme, so that will be in the body tag. The image is in an images folder under the theme on the server. What url would I use to point to the file?
Also, how do I get rid of the site name text (where it says Orchard etc)?
To add a background image, just tweek the css, not the layout.
And to remove the site name, you can use placement.info (see the documentation for that). By using the Shape Tracing module it should be easy for you to figure what shape has to be hidden.
I am tweaking the css as opposed to the layout.The background-image property will need a url to the image on the server (http:// ...). I need to know what this will be? The image is in Themes/MyTheme/Images/bg.jpg
relative urls are css based, so it should be something like ../images/bg.jpg
Are you sure you want to delete this post? You will not be able to recover it later.
Are you sure you want to delete this thread? You will not be able to recover it later. | http://orchard.codeplex.com/discussions/268068 | CC-MAIN-2017-13 | refinedweb | 522 | 83.36 |
import "kylelemons.net/go/esource"
esource.go
var ( // ContentType is sent as the content type for event source handlers ContentType = "text/event-stream;charset=utf-8" // BufferSize is the number of events to buffer per connection before dropping BufferSize = 256 // DefaultBacklog is the default number of events to keep in memory DefaultBacklog = 256 )
type Event struct { ID int // set by the esource library Type string // event type (may not contain newlines or colons) Data interface{} // string (sent raw) or object (will be json encoded) or nil (nothing) }
An Event represents data that can be sent to an EventSource
WriteTo writes the wire encoding of the event to the given wire.
type EventSource struct { // Events receives events to be sent to all listening connections. Events chan<- Event // contains filtered or unexported fields }
An EventSource represents a stream of events that can handle multiple clients.
All methods on EventSource are goroutine-safe, as is sending messages on the Events channel. Methods may not be called and Events may not be sent after the Close method has been called.
func New() *EventSource
New creates a new EventSource.
func (es *EventSource) Close() error
Close causes the EventSource to shut down all connections. The final messages will be flushed to clients asynchronously.
func (es *EventSource) ServeHTTP(w http.ResponseWriter, r *http.Request)
ServeHTTP serves the client with events as they come in, and with any stored events
func (es *EventSource) SetBacklog(backlog int)
SetBacklog adjusts the number of messages that will be maintained in memory in order to be able to catch up clients which reconnect. If more events have been stored than the given backlog, the excess events will be discarded immediately.
func (es *EventSource) Tee(startID int) ([]Event, chan Event)
Tee delivers the events as they would go to a client.
Package esource imports 7 packages (graph) and is imported by 1 packages. Updated 2018-03-10. Refresh now. Tools for package owners. | https://godoc.org/kylelemons.net/go/esource | CC-MAIN-2018-51 | refinedweb | 320 | 67.89 |
Bugz everywhere!!! I must squash them!
Spot the bug :
for (unsigned int i = (unsigned int)((int)list.size() - 1) ; i >= 0 ; --i) {
printf("%u\n" , i);
}.
If size() returns 0, then i would be 4 billion (too lazy to look up the number), assuming the cast to unsigned treats negative numbers that way.
I feel like that's not the bug you're asking us to find though.
---Febreze (and other air fresheners actually) is just below perfumes/colognes, and that's just below dead skunks in terms of smells that offend my nose.MiquelFire.redIf anyone is of the opinion that there is no systemic racism in America, they're either blind, stupid, or racist too. ~Edgar Reynaldo
#include <SDL2/SDL.h>
#include <SDL2/SDL_timer.h>
int main(int argc, char *argv[])
{
SDL_Init(SDL_INIT_EVERYTHING);
SDL_Window* win = SDL_CreateWindow("Welcome to SDL",
SDL_WINDOWPOS_CENTERED,
SDL_WINDOWPOS_CENTERED,
1000, 1000, 0);
SDL_Delay(2000);
}
"For in much wisdom is much grief: and he that increases knowledge increases sorrow."-Ecclesiastes 1:18[SiegeLord's Abode][Codes]:[DAllegro5]:[RustAllegro]
When i reaches 0 and it substracts 1, it wraps around to the maximum value of unsigned int. Therefore, the loop never ends.
GCC knows!
<source>:4:43: warning: comparison of unsigned expression in '>= 0' is always true [-Wtype-limits]
(strangely, clang does too but it's not reported, even with -W -Wall)
SDL_Init(SDL_INIT_EVERYTHING);
Ohhh, can we have al_init_everything()? Instead of:
al_init();
al_init_image_addon();
al_install_keyboard();
al_install_mouse();
al_init_primitives_addon();
al_install_joystick();
al_init_acodec_addon();
al_install_audio();
al_init_font_addon();
al_init_ttf_addon();
Maybe with a bonus version that also creates a display and timer and event queue with everything attached, and a call to al_reserve_samples?
queue = al_init_everything_ex(1280, 720, 60);
// can get the created display with al_get_current_display()
--"Either help out or stop whining" - Evert
That #call-to-action button::before to prevent image loading when hover/clicked causing a very brief flicker...
---ItsyRealm, a quirky 2D/3D RPG where you fight, skill, and explore in a medieval world with horrors unimaginable.they / she
You can do what I did. I wrapped them up in a function and used flags.
//pseudo code
int init(int flags)
{
if (!al_init()) return -1
if (flag & FLAG_IMAGE_ADDON) ...
}
YouTube Channel
The correct code would have been :
for (unsigned int i = list.size() ; i > 0 ; --i) {
printf("%i\n" , (int)i - 1;
}
It's not often you see underflows, but they're there.
EDITEagle init code (verbatim)
Allegro5System* a5sys = GetAllegro5System();
if (EAGLE_FULL_SETUP != a5sys->Initialize(EAGLE_FULL_SETUP) {
EagleWarn() << "Not all modules initialized. Warning.\n";
}
EagleGraphicsContext* win = a5sys->CreateGraphicsContext(800,600 , EAGLE_WINDOWED | EAGLE_OPENGL);
if (!(win && win->Valid())) {
EagleCritical() << "Failed to create window.\n";
}
3 line setup for a window. It serves me right. No more lame queue creation and registration every time you want a window with input. Multiple thread safe windows and more.
....Eagle anyone?....no? well ok then.
----------------------------------------------------Please check out my songs:
That was not an example of a bug, just init code.
Post your bugs!
{"name":"612991","src":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/8\/8\/88c3874f8b5efb365312ba84dabe7fe5.png","w":462,"h":201,"tn":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/8\/8\/88c3874f8b5efb365312ba84dabe7fe5"}From the init code of a microcontroller
Sweet. Hope that microcontroller didn't do anything important.
Ohhh, can we have al_init_everything()
Then I also want al_destroy_everything()
Then I also want al_destroy_everything()
That exists but only people above our pay-grade are allowed to used it.
Here's a bit of a shocker that I did not know about until today, from man abs
SYNOPSIS
#include <stdlib.h>
int
abs(int i);
DESCRIPTION
The abs() function computes the absolute value of the integer i.
RETURN VALUES
The abs() function returns the absolute value.
So far, so good, but then:
BUGS
The absolute value of the most negative integer remains negative.
That's because signed integers have an extra negative number compared to positive numbers, for example, for an 8 bit value, we have -128 to 127.
That's because signed integers have an extra negative number compared to positive numbers, for example, for an 8 bit value, we have -128 to 127.
You know this and I know this. But I'm sure I've never written code to account for it
x = abs(x);
if (x >= 0) {
something(x);
} else {
error();
}
I don't think there's a better option either, returning zero or INT_MAX or anything else would also lead to silent errors. And C doesn't usually raise a signal for integer arithmetic (? does it?)
I'm trying to think if a way in which the negative number issue with abs would matter anyway. With signed 8-bit, if -128 is a possible value, what's stopping you from getting -150 before you call abs? I think the times you need to worry about the minimum number being passed to abs, you have to worry about the value being out of range for the integer type you are using anyway. | https://www.allegro.cc/forums/thread/618435 | CC-MAIN-2022-33 | refinedweb | 807 | 56.45 |
On Mon, Apr 07, 2003 at 06:34:17PM +1000, Rusty Russell wrote:> Oh good: a serious question. Why don't we drop the personality field> in struct task_struct and just use exec_domain? Then the flags could> be unfolded from the personality number, and placed in a "flags"> element in struct exec_domain, the personality() macro would vanish,> the set_personality() macro would vanish, and things would be> generally clearer?The personality number is exposed through sys_personality, so unfortunatelywe can't get rid of it. I still wonder what crack the person inviting thisscheme was smoking, though..> That applies to any kernel mod, of course. qemu is much more usable> (ie. it's sanely packagable) with this functionality, ie. it's pretty> much a requirement for increasing adoption.You can just easily let it run in a chroot or separate namespace,you just won't get second look semantics. (Personally I think that'sa benefit, but some people disagree with this).-To unsubscribe from this list: send the line "unsubscribe linux-kernel" inthe body of a message to majordomo@vger.kernel.orgMore majordomo info at read the FAQ at | http://lkml.org/lkml/2003/4/7/201 | CC-MAIN-2017-34 | refinedweb | 187 | 58.08 |
Hi Nik,
thanks for replying. I looked for namesspaces that's for the entries
itself but not for how the file will look like or how it is created. Of
course I could apply some xslt afterwards ... but I wonder if their is a
plugin like way to do that.
Konstantin
On Mon, 2009-05-04 at 12:30 +1000, Nik wrote:
> Konstantin Rekk wrote:
> > Hello,
> >
> > I wonder if there is a way to influence the way install is creating
> > ivy.xml from maven repositories, for example by providing a template or
> > similiar or pluging in some custom strategy?
> >
> I'm not sure exactly what you're trying to change, and I'm certainly not
> an expert on this, but have you looked at the "namespace" example in the
> "build your own repository" tutorial?
>
> Cheers!
> Nik
>
> PS: Apologies for the delayed - I sent the original from the wrong id. | http://mail-archives.apache.org/mod_mbox/ant-ivy-user/200905.mbox/%3C1241464176.17268.2.camel@myhome%3E | CC-MAIN-2015-11 | refinedweb | 149 | 70.53 |
Quickstart: Use your own notebook server to get started with Azure Machine Learning
Use your own Python environment and Jupyter Notebook Server to get started with Azure Machine Learning service. For a quickstart with no SDK installation, see Quickstart: Use a cloud-based notebook server to get started with Azure Machine Learning.
This quickstart shows how you can use the Azure Machine Learning service workspace to keep track of your machine learning experiments. You will run Python code that log values into the workspace.
View a video version of this quickstart:
If you don’t have an Azure subscription, create a free account before you begin. Try the free or paid version of Azure Machine Learning service today.
Prerequisites
- A Python 3.6 notebook server with the Azure Machine Learning SDK installed
- An Azure Machine Learning service workspace
- A workspace configuration file (.azureml/config.json).
Get all these prerequisites from Create an Azure Machine Learning service workspace.
Use the workspace
Create a script or start a notebook in the same directory as your workspace configuration file (.azureml/config.json).
Attach to workspace
This code reads information from the configuration file to attach to your workspace.
from azureml.core import Workspace ws = Workspace.from_config()
Log values
Run this code that uses the basic APIs of the SDK to track experiment runs.
- Create an experiment in the workspace.
- Log a single value into the experiment.
- Log a list of values into the experiment.
from azureml.core import Experiment # Create a new experiment in your workspace. exp = Experiment(workspace=ws, name='myexp') # Start a run and start the logging service. run = exp.start_logging() # Log a single number. run.log('my magic number', 42) # Log a list (Fibonacci numbers). run.log_list('my list', [1, 1, 2, 3, 5, 8, 13, 21, 34, 55]) # Finish the run. run.complete()
View logged results
When the run finishes, you can view the experiment run in the Azure portal. To print a URL that navigates to the results for the last run, use the following code:
print(run.get_portal_url())
This code returns a link you can use to view the logged values in the Azure portal in your browser.
Clean up resources
Important
You can use the resources you've created here as prerequisites to other Machine Learning tutorials and how-to articles.
If you don't plan to use the resources that you created in this article, delete them to avoid incurring any charges.
ws.delete(delete_dependent_resources=True)
Next steps
In this article, you created the resources you need to experiment with and deploy models. You ran code in a notebook, and you explored the run history for the code in your workspace in the cloud.
You can also explore more advanced examples on GitHub or view the SDK user guide.
Feedback | https://docs.microsoft.com/en-us/azure/machine-learning/service/quickstart-run-local-notebook | CC-MAIN-2019-30 | refinedweb | 465 | 64.61 |
Flutter is a cross-platform development framework that allows us to create iOS and Android apps using a single programming language called Dart, which was released by Google itself.
I would like to share a few things I wish I would have known before starting Flutter as an iOS developer.
Dart programming language
Like Android uses Java/Kotlin and iOS uses Objective C/Swift programming languages to build Android and iOS apps, Flutter uses Dart programing language. You can Get Started from here with learning Dart.
Dart supports all the features for the Object-oriented programing paradigm(OOP). It is a C-like language with brackets and semicolons. It is uneasy to grasp for swift developers, but it is not hard to learn and use.
DartPad and CodePen
In iOS we have Playground, to test our Swift code. Similarly, we have DartPad and CodePen for the Dart programming language.
DartPad: It is an online editor that runs Dart programs directly in our browser and also renders a real preview of a screen/widget. It’s an easy way to test some of the business logic of Flutter apps. We can experiment with our Dart code in this editor.
CodePen: CodePen is an online editor for HTML, CSS and JavaScript. Recently it was announced that CodePen supports Flutter. One of the advantage of CodePen over DartPad is that DartPad uses GitHub gists to publicly share our code while in CodePen we can share our code directly by sharing Url.
IDEs
For Android developers, it’s easy as Flutter supports Android Studio. For iOS devs - maybe not harder, but a little different than Xcode. Flutter is available on different IDEs. The two main code editors are:
Android Studio(IntelliJ): It’s a complete software with everything already integrated. You have to download Flutter and Dart plugins and set up Flutter SDK to start.
VSCode: It is used for developing Flutter and Web applications. It is lightweight and fast. You should first install Dart and Flutter SDK extensions from VS Code market and then set up your SDK
For more detail click here
Widgets
Flutter uses the concept of the Widgets which can be used to build complex user interfaces. It is easy to create our own widgets or customize existing widgets. You can browse a catalog of Flutter’s widgets here and view, for example, Material Design widgets for Android and Cupertino widgets for iOS.
Flutter uses declarative UI. SwiftUI looks a lot like Flutter but SwiftUI requires iOS 13 and works only with Apple Products. Whereas Flutter is not dependent on OS version and works cross-platform i.e Flutter works with the earlier version of iOS.
Every component in Flutter is known as a Widget. The Flutter apps are created by combining these widgets (like building blocks) to form a widget tree. Even the final app we get is also a widget.
For Example - Text Widget
Text( 'Hello World', style: TextStyle( fontSize: 18.0, color: Colors.grey[600], ), )
Note: Every program starts with main function which is the entry point of our application.
Stateless and Stateful widget
The Flutter UI is basically a tree of stateless or stateful widgets.
Stateless Widgets:These widgets are immutable, so they cannot change their state during runtime. i.e won’t change when a user interacts with them.
For example - Text, Icon, etc are the stateless widgets that will remain static.
Stateful widget:These widgets are mutable, they change over time. These widgets can change their state multiple times and can be redrawn on to the screen any number of times while the app is in action.
For example - Checkbox, Radio, etc are the stateful widgets that change as a user interacts with them.
JIT (Just-In-Time)
Dart uses JIT compilation. Flutter allows for fast app reloading by providing a Hot Reload option. You don’t have to restart the app for every change. Just press the
Hot Reload button on the toolbar or press
cmd-s(Save All) to the running Dart VM to send incremental changes of source code, which will reload the changes on device or simulator in few seconds.
Dependency management
The dependency management for iOS depends on CocoaPods or Carthage. Flutter uses its own dependency management system called Pub. The
pubspec.yaml file is inbuilt with the Flutter apps so that it’s easy to add new dependencies as needed for the development.
For example - I want to use the Equatable Flutter package.
Note: For every Flutter package please check out the installing option. For an equatable package, I’ll copy the text from here and paste it in pubspec.yaml.
My pubspec.yaml file will look like this
dependencies: equatable: ^1.1.1
and then run command
pub get on the terminal to install the package.
For using Assets and Fonts: Drag and drop your assets and fonts in your app and add them to pubspec.yaml file.
For example - I’ve created two folders:
assets and
fonts and inside, I’ve added the image
image1.jpg and font
IndieFlower-Regular.ttf. My pubspec.yaml file will look like this:
assets: - assets/image1.jpg fonts: - family: IndieFlower fonts: - asset: fonts/IndieFlower-Regular.ttf
and then run command
pub get on terminal to use them.
Importing files and packages
If you want to use any files or packages in your current file, then you have to import that file or package.
For example - I want to use the
equatable package. Then I will import like this:
import 'package:equatable/equatable.dart';
Flutter example
You can install Flutter SDK by following instructions from here
Create New Flutter Application. You can see the Sample App that Flutter has created for us and when you run it looks like this:
If you compare the simulator screenshot and code with the above tree, I hope you will understand the basics of UI structure. The code looks like this:
import 'package:flutter/material.dart'; void main() { runApp(MyApp()); } class MyApp extends StatelessWidget { @override Widget build(BuildContext context) { return MaterialApp( title: 'Flutter Demo', theme: ThemeData( primarySwatch: Colors.blue, visualDensity: VisualDensity.adaptivePlatformDensity, ),), ), ); } }
References
Ray Wenderlich - Getting started with Flutter | https://engineering.monstar-lab.com/2020/04/21/Things-iOS-developer-should-know-before-starting-flutter | CC-MAIN-2020-45 | refinedweb | 1,024 | 65.73 |
Chatting
Chatting how to invoke the code from JTextArea to send Socket.getInputStram()&Sockeck.getOutputStream
|
Hibernate Tutorial |
Spring Framework Tutorial
| Struts Tutorial...;
JAVA SECTION
Java
Tutorials |
Java Code... | JDBC Tutorial
| EJB
Tutorials | JSF Tutorial |
WAP Tutorial |
embedding a chatting code in jsp page - JSP-Servlet
embedding a chatting code in jsp page i need to know that how can i embed my chatting code in java networking in my jsp page
retail invoice and billing source code in struts
retail invoice and billing source code in struts Hi.
I need source code for "retail invoice and billing source code in struts", Please help me in doing so. Please It's important and urgent
JavaScript array index of
Download Source code...JavaScript array index of
In this Tutorial we want to describe that makes you to easy to understand
JavaScript array index of. We are using JavaScript
one to many video chatting in web application
one to many video chatting in web application Hi all....I am developing a web application,where video chatting is its one of the main feature.Can... technology.If possible give me the code for the same
Shopping Cart Index Page
Modules in a application
Working Of An Application
Download Source Code
Download Source Code (As WAR file
calendra.css source code - Java Beginners
calendra.css source code hello i need the source code... and year are getting displayed Hi Friend,
Try the following code...;
background-color: #EEE;
display: none;
position: absolute;
z-index: 1;
top: 0px
Search index
Search index how to write code for advanced search button
Pointing last index of the Matcher
;^29
DownLoad Source Code...
Pointing last index of the Matcher
... and also indicate the last index of the matcher using expression.For this
JavaScript array index of
JavaScript array index of
... to easy to understand
JavaScript array index of. We are using JavaScript...)index of( ) - This return the position of the value that is hold
Source code
Source code source code of html to create a user login
chatting Server
chatting Server I want to develop a chatting server in jsp using mysql as database.What I need for that.
Please tell me
source code
source code hellow!i am developing a web portal in which i need to set dialy,weekly,monthly reminers so please give me source code in jsp
source code
source code how to use nested for to print char in java language?
Hello Friend,
Try the following code:
class UseNestedLoops{
public static void main(String[] args){
char[][] letters = { {'A', 'B'}, {'C','D
Java Chatting
Java Chatting Hai Sir,
Give me some idea about how to do chatting program in java.I am familiar with java web applications.Pleaes help me sir.I... their homepage.But now i want to give chatting facility to my user with admins.Kindly
Struts - Struts
Struts hi,
I am new in struts concept.so, please explain example login application in struts web based application with source code .
what are needed the jar file and to run in struts application ?
please kindly
Struts - Struts
compelete code.
thanks Hi friend,
Please give details with full source code to solve the problem.
Mention the technology you have used...Struts Hello
I like to make a registration form in struts inwhich
OGNL Index
Introduction of OGNL in struts.
Object Graph Navigation Language... code more readable.
It acts as a binding language between GUI elements and model objects.
The Struts framework used a standard naming context for evaluating
Struts - Struts
with source code to solve the problem.
For read more information on Struts visit...Struts Hello
I have 2 java pages and 2 jsp pages in struts
registration.jsp for client to register user
registeraction.java to forward
org.apache.commons.dbcp.DbcpException - Struts
org.apache.commons.dbcp.DbcpException I have wrox book struts source code(employee)
When call the index.jsp,it shows exception like:
how...)
at org.apache.jsp.index_jsp._jspService(index_jsp.java:56
source code for the following question
source code for the following question source code for the fuzzy c-means
Download and Build from Source
Of An Application
Download Source Code...
Download and Build from Source
Shopping cart application developed using Struts 2.2.1 and MySQL can be
downloaded from
Java source code
Java source code How are Java source code files named
index - Java Beginners
;Hi Friend,
Try the following code:
import java.io.*;
import java.awt.
index
PHP Based Chatserver - Design concepts & design patterns
PHP Based Chatserver Hey i want to create a Chat server like this one : could someone plz tell me were can i get a chatserver
jsp code - JSP-Servlet
(which runs on client side). This application is using for chatting in LAN. To start chatting you must be connected with the server after that your message can... visit to :
Thanks
source code in jsp
source code in jsp sir...i need the code for inserting images into the product catalog page and code to display it to the customers when they login to site..pls help
struts internationalisation - Struts
code to solve the problem :
For more information on struts visit...struts internationalisation hi friends
i am doing struts iinternationalistaion in the site
Source Code - Java Beginners
JavaScript array remove by index
code of array remove by index in
JavaScript is as follows:
javascript_array... Source Code...
JavaScript array remove by index
Finding start and end index of string using Regular expression
Source Code...
Finding start and end index of string using Regular expression... the way for finding start and end index of the string using
regular expression
Download Struts
/download.cgi page.
Downloading source code:
If you are interested in the source code of the Struts
framework you can download the source code from
http... index page
Struts 2 Tutorials
Struts 1 Tutorial
Best Open Source Software
(and sometimes incorrectly) called freeware, shareware, and "source code," open... of intellectual property assets in the form of source code for both reference... impatient can consult the index below.
Open source' software
Index Out of Bound Exception
Index Out of Bound Exception
Index Out of Bound Exception are the Unchecked Exception... passed to a
method in a code. The java Compiler does not check the error during
Open Source Jobs
the source code is available to the general public for use and/or modification from its original design free of charge. Open source code is typically created... that source code must be available. ``If it's not source, it's not software - History of Struts 2
for navigational code. All these together makes Struts an essential framework for building...
Struts 2 History
Apache Struts is an open-source framework that is used for developing Java web application. Originally
Source code of a website in HL and JSP.
Source code of a website in HL and JSP. I want the source code of a website of 10 pages with database connectivity. Source code should be in HTML and JSP. Thanks
Struts <s:include> - Struts
the source code the content is blank and is not included.
am i going wrong somewhere? or struts doesnt execute tags inside fetched page?
the same include code... with source code to solve the problem
and visit to :
What is Struts
and their associated Java classes.
Struts is open-source and uses Java... tutorials at the index
page of Struts Tutorials...Apache Struts is used to create Java web applications using Java Servlet API
Foreach loop with negative index in velocity
Index: -2
Download
code...
Foreach loop with negative index
in velocity
... with negative index in velocity.
The method used in this example
struts opensource framework
struts opensource framework i know how to struts flow ,but i want struts framework open source code
java source code - Java Beginners
java source code write a program to read the value of n as total number of friend relatives to whom the person wants to call
Need source code - Swing AWT
Need source code Hai,
I need a idea and code for developing the project "Face Recognition" with the backend as My-sql....
Thanks & Regards
Advertisements
If you enjoyed this post then why not add us on Google+? Add us to your Circles | http://www.roseindia.net/tutorialhelp/comment/89776 | CC-MAIN-2015-18 | refinedweb | 1,365 | 64.81 |
AN034 Singleton
On Particle devices, using the singleton pattern is often handy. A singleton class only has a single instance per application, and is protected against creating more. This is common when interacting with a hardware peripheral where there can only be one of them, or other code where you only want one class instance.
Why a singleton?
Say, for example, you're communicating with a LCD display for your device. If you have a class to manage the display state and communicate with it, you probably only want one instance of the class. Not only will multiple instances take up valuable RAM, they could cause concurrent access to corrupt the display.
But why not a global?
A common design in Arduino is to create a global variable for the class in your main application file. This works, however there are some caveats:
The main issue is with global object constructors. There are numerous limitations on what you can include in a global object constructor because the order of initialization is not guaranteed by the C++ compiler. It's completely non-deterministic, so making even minor changes will sometimes cause the order to change unexpectedly. This can also be an issues on compiler upgrades.
Additionally, once more than one module needs the object, things start to get tricky. You need to pass an object reference to each module that needs it, which can run into a circular dependency problem. Accessing the global with
extern can run into the global object constructor ordering issue.
What is the solution?
The solution is to have each class maintain its own object pointer, which is allocated on the heap when first used. An object method returns this singleton instance.
Since global object construction is not used, all of the caveats pertaining to that are no longer an issue.
And since the object is not globally allocated, you can include the singleton in a library and if no code uses it, the linker will remove the code from your application, saving space. This is handy if you have code that's different on Wi-Fi and cellular, but you build on both. Or have code that's specific to Gen 2 or Gen 3 devices and build for both.
How do I do it?
This is not the only way you can implement the singleton pattern, however it's similar to how it's used in the Tracker Edge reference firmware, and it's one I've used in numerous libraries and is known to work well. The code walk-through corresponds to the code generated by the code generator, below.
Main application file
Your main application file will probably look something like this, but with more code.
#include "MyClass.h" SYSTEM_THREAD(ENABLED); SerialLogHandler logHandler; void setup() { MyClass::instance().setup(); } void loop() { MyClass::instance().loop(); }
- Include your header file, in this case,
#include "MyClass.h".
- From
setup()call
MyClass::instance().setup().
- From
loop()call
MyClass::instance().loop().
Not all applications will need both setup and loop, however you never really know when you might need it in the future and having both ready in every app will make things easier later if you need them. The overhead is very small.
MyClass::instance()
This construct is used for the singleton instance.
It's declared like this in the .h file:
static MyClass &instance();
and implemented like this in the .cpp file:
MyClass &MyClass::instance() { if (!_instance) { _instance = new MyClass(); } return *_instance; }
If the static class member
_instanceis NULL, then one is allocated with
new. If it already exists, then the existing instance is returned quickly.
_instanceis a pointer (
MyClass *) but the
instance()method returns a reference (
MyClass &).
Both reference the existing object (not making a copy), but using a reference (
MyClass &) allows the caller to use
MyClass::instance().setup()instead of
MyClass::instance()->setup(). Both work, and it somewhat of a stylistic choice to which you prefer.
Some may notice that _instance is dereferenced without checking for NULL. This is intentional because if that allocation fails, you have a really serious out of memory condition, and propagating the error up greatly complicates all of the code because Particle devices do not have exceptions enabled. The code will cause a SOS+1 hard fault on out-of-memory, but this will typically occur during
setup() where if you will likely discover this during development and it will be obvious that something is very wrong.
Also, technically the implementation is not thread-safe. However, the way you use it is to instantiate it from early in setup(), before other threads are created, so in practice it will work properly if you use it in the way that is recommended.
Protected constructors
Just to make sure you don't accidentally try to instantiate
MyClass as a global, on the stack, or with new. The constructor is declared
protected. (
private would have worked a well). This will cause a compilation error if you use the singleton incorrectly.
protected: /** * @brief The constructor is protected because the class is a singleton * * Use MyClass::instance() to instantiate the singleton. */ MyClass(); /** * @brief The destructor is protected because the class is a singleton and cannot be deleted */ virtual ~MyClass();
For example:
main.cpp:6:9: error: 'MyClass::MyClass()' is protected within this context 6 | MyClass myClass; | ^~~ In file included from main.cpp:1: MyClass.h:45:2: note: declared protected here 45 | MyClass(); | ^~~~~~~ main.cpp: In function 'void __static_initialization_and_destruction_0(int, int)':
Copy prevention
Another common programming error is trying to copy a pointer to the class to a variable or copying by reference. You shouldn't do that and should always call
MyClass::instance() and that's prevented with these two lines:
/** * This class is a singleton and cannot be copied */ MyClass(const MyClass&) = delete; /** * This class is a singleton and cannot be copied */ MyClass& operator=(const MyClass&) = delete;
Thread support
Another common scenario is when you want to also implement a worker thread for your code, one per singleton class.
setup() (with thread)
While the plain boilerplate
MyClass::setup() doesn't do anything, the thread version does. It initializes the mutex to protect shared resources and creates the thread.
The constant
3072 is the size of the stack (3K). You can adjust this up or down as desired.
void MyClass::setup() { os_mutex_create(&mutex); thread = new Thread("MyClass", [this]() { return threadFunction(); }, OS_THREAD_PRIORITY_DEFAULT, 3072); }
Thread function as a class member
This code is a handy trick:
[this]() { return threadFunction(); }
The declaration of the thread function is
std::function<os_thread_return_t(void)>. It's a function with this declaration:
os_thread_return_t myFunction(void);
It cannot be a C++ member function that's not declared
static because the
this pointer is not available to the callback.
Since the parameter is a
std::function, however, it can be a C++11 lambda, which is what the expression
[this]() { return threadFunction(); } is.
It captures the
this pointer, then uses it to call the threadFunction() which is a C++ member function.
Another way to solve this problem is to create a static member function like this and pass
threadFunctionStatic when creating the thread.
static void threadFunctionStatic(void) { MyClass::instance().threadFunction(); }
Mutex wrappers
The code generator also creates lock methods:
/** * @brief Locks the mutex that protects shared resources * * This is compatible with `WITH_LOCK(*this)`. * * The mutex is not recursive so do not lock it within a locked section. */ void lock() { os_mutex_lock(mutex); }; /** * @brief Attempts to lock the mutex that protects shared resources * * @return true if the mutex was locked or false if it was busy already. */ bool tryLock() { return os_mutex_trylock(mutex); }; /** * @brief Unlocks the mutex that protects shared resources */ void unlock() { os_mutex_unlock(mutex); };
These are compatible with
WITH_LOCK().
For example, you might have code like this to make sure only one thread can access your peripheral device at a time.
uint8_t MyClass::readStatusRegister() { WITH_LOCK(*this) { return readRegister(REG_STATUS); } }
thread function
Finally, you put the code you want to run in the
threadFunction. It's a class member so it has access to all class members (including the mutex). It typically runs forever - you never return from it.
In order to yield CPU time to other threads, you either call
os_thread_yield() or
delay(), both of which will yield the CPU.
os_thread_return_t MyClass::threadFunction(void) { while(true) { // Put your code to run in the worker thread here os_thread_yield(); } }
Code generator
It's not difficult to write the necessary boilerplate code, but it is an annoying repetitive task. You can use the tool below to generate the singleton and optional thread code to use as the basis of your new class. | https://docs.particle.io/datasheets/app-notes/an034-singleton/ | CC-MAIN-2022-21 | refinedweb | 1,424 | 54.42 |
Abstractions in general
Abstraction is a result of a process to generalize the context and arrange and hide the complexity of the internals. The whole computer science is based on this idea and if you are a front-end developer, there are multiple layers of abstractions already under the code you are writing. Abstraction is a very powerful concept and it speeds up development hugely if done correctly.
We see abstractions all around us and not just in software development. For example, automatic transmission in a car has two gears, R, D. These shifts abstract the necessary action to make the car either forward or backward so that the user can focus on driving. For example, if a user wants to make a car to go backward, the only two actions the user needs to think is putting the shift into R(everse) and pressing a gas pedal.
The same goes for programming where we continuously use abstraction. It begins at a very low level where the charge of the electrical current is converted into zeros and ones and goes all the way up to the ideas of the application you are developing. On a higher level, abstraction can be for example functions that standardize certain processes or classes which create structures for the data.
In React abstractions are done by using composition. Higher-level components combine standardized lower-level components to be part of the user interface together. For example, a button could be part of the feedback form which can be part of the contact page. Each of the levels hides relevant logic inside the component and exposes necessary parts outside.
For example, if we have a component that is responsible for an accordion, we can reuse the same component instead of re-writing it when we want an accordion to be part of the screen. We may need to have a different design or a bit different functionality but as long as the accordion in a screen acts as accordion, we can reuse the base functionality.
The key to success with the composition is to find the right abstraction layers for the project's components. Too many and too few layers of abstraction risk having redundant code and decelerating development speed. Too large abstraction layers mean that smaller common code components are repeated in each component. At the same time, too small abstractions repeat the usage of the components more than needed and having too many layers of code will slow the initial development.
The proper levels of abstraction are hard to estimate before the significant parts of the application are ready and incorrect abstraction levels are the usual a cause for the need of refactoring later on. Defining the responsibilities of the components before development helps to reduce the amount of needed refactoring because it forces to justify the decisions. I can also suggest to create a bit too many abstraction layers than too few because layers are easier and cheaper to combine.
In our accordion example, we first decided to expose the reveal and collapse functionality and color theme outside which means that accordion isn't any more responsible for that. This also means that we expect those two properties to differentiate a lot between the screen. Analyzing and determining the responsibilities for the components will help out see how components should be built the way that they are composable for your application. For me, this became obvious when in the latest project I have been involved.
Case: Forms in frontend of enterprise application
Around a year ago we started to build an application to speed up one of the company's processes. As usual with all these kinds of business applications, the software would handle user inputs to fill the necessary data and then turn it to a product. I'll use this project to showcase how the abstraction worked for us. I'm going to focus on how we build forms since they were the key for this software and they ended up being the best example of an abstraction that I have done.
Starting a project
Let's start with the starting point to get some understanding of the factors leading up to the decision we took. When the project began, the final state of the process was unknown like it usually is in agile development. Nonetheless, this allowed us to deal with a lot of uncertainty when defining abstracts, leading to much more careful analysis before the components were defined.
In the context of forms, the base requirements were that we could have multiple of forms with different inputs. For me, this meant that we should make the form components extendable to as many situations as we could think while keeping the core as standard as possible.
How we abstracted forms
Before we could start building the abstractions, we needed to understand the purpose of the forms. In our case, they are part of the process where a user can either create new data or alter the current data. While most of the data points are independent of each other, we still wanted to ensure that we can handle dependency either between the form fields or between a form field and a value from the server.
The purpose of the fields is also to limit the given set of values. Data types are the general cause to limit the input. For example, when requesting a number input, we should limit users' ability to give something else. We also should be able to limit the input to a certain list of values by either limiting the input or validating the input.
This process showed that we should have two abstractions; form and form field. Besides that, we noticed that we may have different types of fields if we want to limit the input in different ways.
Form
Based on the previous process description we decided that the form in our case will be responsible for handling the state of the form data and validations. It should be also possible to give initial values and trigger the submit. The form shouldn't care where initial values come from or what happens on submit which means that these two should be exposed.
const Form = ({ initialValues, onSubmit, children }) => { return children({ ... }) }
Field
For the fields, we defined that we would need different types of limits for what the user can inputs. If there would be just a couple of different options it would make sense to include the logic inside the abstraction. For us, it was obvious from the beginning that we would have a lot of different types of data so we should expose the logic outside. And this wouldn't be only the logic but also UI part of each limit. For example, when we want user only to choose from the list, we should create a UI (ie. a drop-down) for that.
All field elements also had some common elements like a label on the top or the side of the input and possible error or information message under the input. These we decided to include inside the abstraction since we expected these to be part of the all form fields.
The result of these two decisions ended up creating two different abstractions. A field that is responsible for the data and surroundings of the input and an input type that is responsible to show the input field. Each of the different input types like TextInput would be their components which would all fill the same responsibility but a different way.
const Field = ({ name, label, inputComponent: Input, inputProps }) => { const value = undefined /* Presents the value */ const onChange = undefined /* Changes the value */ return ( <React.Fragment> {label} <Input name={name} value={value} onChange={onChange} {...inputProps} /> </React.Fragment> ) } // Text input in here is an example // The props would be the same for all inputTypes const TextInput = ({ name, value, ...props}) => (...) const App = () => ( <Form> <Field label='Test input' name='TestElement' inputComponent={TextInput} /> </Form> )
Executing the abstraction
After we got the abstractions and requirements for those abstractions ready, it was clear that our setup is universal so someone else should have solved the problem already. Using a ready-made package would ease our job because we wouldn't have to build everything from scratch. After some exploration, we ended up using Formik inside our abstraction.
I would like to note that we are not exposing Formik to our application fully but only on Form and Field level. Formik is only filling the functionality of the abstraction, not creating it for us. This gives us an option to replace the package if we ever need something different in the future and we can also extend our abstraction beyond what Formik provides. The downside of this practice is that we need to write additional integration tests to ensure that Formik works along with our components as it should.
Creating input types
The last piece from the form setup was the input types. Since on the Field level we exposed the input, we would need to have a separate component to fill the responsibility.
It became very obvious while we had created some of these input types that besides data types (ie. text, number, date), the input type component depends on how we want to limit users' selection. For example text, input and group of radio items serve the same purpose but limit the selection very differently. We ended up having roughly 20 different input types in our application. The reason for so many components was that we wanted to abstract each input separately. For example text and number, input looks almost the same but they act differently. For the developer, it would be also easier to distinguish the inputs if they are different components.
This didn't make us repeat a lot of code since the input components were composed of smaller components. I have liked very much the way atomic design splits components because it describes the abstraction layers reasonably well and helps to keep components composable.
For inputs we created two abstraction layers:
- Atoms - single functionality component like the design of the input field, functionality of a tooltip popup.
- Molecules - composes atoms to build higher-level items like in our case input type component.
In our case, for example, the input component was reused between half of the input components because it was so generic. Probably the best example of having composable atoms in our case is Datepicker.
Datepicker example
In the beginning, we used the browser way to handle dates but since we wanted to have the same looking field in all browsers, we decided to do our own. After exploring the available packages and we decided to use fantastic @datepicker-react/hooks hooks and create our design on top of that.
Since we already had a lot of atoms developed, we only needed to create the calendar design which took something like 1.5 days to do from start till the end including tests. In my opinion, this demonstrates the power of the well-chosen abstraction layers which help to generalize the small component into composable atoms.
Conclusions
Generic abstract and composable components speed up development as each new feature also generates reusable components. Once we started developing the Datepicker, this became obvious to us. We've already had all the other components except the calendar itself.
Defining responsibilities for the abstracted components eases up selecting the exposed and hidden logic inside the component. It makes the conversation more constructive within the team as we end up talking about architecture rather than implementation. For example, we specified at the beginning that we expose the input component outside of our Field component. The strongest reasoning for this was that we may end up with a significant amount of different types of fields and we don't want to limit usage inside the field.
Structuring the abstraction layers with some rules helps to declare the responsibilities and connection between abstraction layers. We used atomic design as a base for these rules. It defines five abstraction layers and gives them high-level responsibilities. This helps in the beginning to establish components which have the same abstraction level.
Thanks for reading this. If you have had same experience or have any comments or questions, I would gladly hear them.
Discussion (4)
Thanks for the amazing article. I built a similar library to manage forms on my own which is more or less the same concept (Form, Field, etc) and works fine. The only issue I faced was related to image uploader with thumbnail because onSubmit it updates the state and it re-renders the fields again and images were flickering.
I will give formik a try, probably it will solve my problem.
Thanks :)
I have been using and trying a punch of different form packages and for me Formik has worked the best so far.
Great article. It feels really nice to read. Thanks.
Big thanks! :) | https://dev.to/akirautio/abstractions-in-react-and-how-we-build-forms-50d8 | CC-MAIN-2021-49 | refinedweb | 2,155 | 51.68 |
Print ArrayList from another Class - java
Evening everyone,
I am writing a code to allow students to search for internships. I have a class for Semesters, a class for Students(where student input is taken and stored into an ArrayList and the actual iSearch class. My code is basically doing everything I need it to do, except I have hit a brain block in trying to figure out the best way to output my ArrayList from the Student class out at the end of my program in the iSearch Class.
I am fairly new to Java, so if I haven't explained this correctly please let me know. I am trying to get the ArrayList's of student information to output at the end of the while loop in the iSearch Class.....so
To make this easy. Is it possible to print an Arraylist from another class.
A better way to solve this is to create a Student object for each student. In your current class the ArrayLists you are creating are deleted after every method call, since it is not referenced anymore.
Here is how I would do it:
Student Class:
public class Student {
String firstName;
String lastName;
String interest;
public Student(String firstName, String lastName, String interest) {
this.firstName = firstName;
this.lastName = lastName;
this.interest = interest;
}
public String getFirstName() {
return firstName;
}
public String getLastName() {
return lastName;
}
public String getInterest() {
return interest;
}
}
In your iSearch class you create an ArrayList of students, which lets you add your students:
ArrayList<Student> students = new ArrayList<Student>();
do {
String firstName = input.next();
String lastName = input.next();
String interest = input.next();
students.add(new Student(firstName, lastName, interest));
} while (YOUR_CONDITION);
Then you can display each student by iterating through the ArrayList and accessing the getter and setter methods:
students.foreach(student -> {
System.out.println(student.getFirstName());
System.out.println(student.getLastName());
System.out.println(student.getInterest());
});
Editing this a little will help you to solve your problem, but this is the basic solution.
Related
why is my my class giving me an error for the return?
Now i got it set as a constructor, however I am unsure how to actually use this. I want to be able to store the first name, last name and degree level. I need it to continue to run until I stop it and continue with more of the program. import javax.swing.*; import java.util.ArrayList; public class Tutor { public Tutor(String firstName, String firstName, String degreeLevel) { firstName = firstName; lastName = firstName; degreeLevel = degreeLevel; } public static void main (String[] args) { String fName; String lName; String level; String ans; ArrayList<String> listOfTutor = new ArrayList<String>(); for (int i = 0; i<listOfTutor.size();); } } } Edit import javax.swing.*; import java.util.ArrayList; public class Tutor { String firstName; String lastName; String degreeLevel; public Tutor(String firstName, String lastName, String degreeLevel) { this.firstName = firstName; this.lastName = firstName; this.degreeLevel = degreeLevel; } public static void main (String[] args) { String fName; String lName; String level; String ans; ArrayList<Tutor> listOfTutor = new ArrayList<Tutor>(); for (int i = 0; i<3;); } } }
You did a lot of wrong there: First: If Tutor is a Method: You have to set a Return Type to your Method. public static String Tutor(...) This way your Method returns your values correctly. Second: If Tutor should be your Class: Then you have to rename either your class to Tutor or your Constructor to CalculateATutor. A constructor never has a Return Type and never contains a return-Statement. So this way you have to delete your return-Statement in your Constructor. public CalculateATutor(String firstName, String lastName, String degreeLevel) { this.firstName = firstName; this.lastName = lastName; this.degreeLevel = degreeLevel; } Third: The usage of your Class Tutor (if it is a class) is wrong String ans; List<Tutor> myTutor = new ArrayList<Tutor>(); //You have to specify Tutor in your Template-Class for (int i = 0; i<myTutor.size; i++) { ans = JOptionPane.showInputDialog(null,"Enter Tutor's Last Name, First Name, and Highest Level of Degree:"); //Here you have a lot to do because you get one inputstring with all 3 Elements //You have to split the input or get 3 seperate inputs // We assume you have your correct input here right now with Strings fname, lname, level Tutor t = new Tutor(lname,fname,level); myTutor.add(t); } } EDIT: To your new Question: You have to declare local variables into the class. public class TestClass{ String lastName; public TestClass(String lastName){// this is the Constructor this.lastName = lastName; } } This way you can store the Variables.
You need getting the error because the Tutor() function is returning a value, but no return type is given in the method declaration. If you want your function to return a String: public String Tutor(String firstName, String lastName, String degreeLevel) ^^^^^^ There are actually many problems in the code currently. I believe what you're trying to do is make Tutor() a constructor. If that's the case, it's declaration should be: public CalculateATutor(String firstName, String lastName, String degreeLevel) because CalculateATutor is the name of the class. It should not return anything. Additionally, these lines: this.firstName = firstName; this.lastName = lastName; this.degreeLevel = degreeLevel; will not work the way you want. If you're attempting to set class fields, you need to declare the fields in your class first. Like this: public class CalculateATutor { String firstName; String lastName; String degreeLevel; ... }
public String Tutor(String firstName, String lastName, String degreeLevel) ^ missing as you are returning String return(lastName +", "+ firstName +" "+ degreeLevel); Instead our answers try to understand compiler's error message: error: invalid method declaration; return type required ^ function declaration is wrong Also says return type required So you forgot return type of function. Where function name is public Tutor()
public Tutor(String firstName, String lastName, String degreeLevel) should be public String Tutor(String firstName, String lastName, String degreeLevel)
The error message is telling you what to do. all Java methods/functions have to be declared with a return type. In this case it appears to be a String, so it becomes public String Tutor() If you dont want it to return anything then it is public void getMiau()
Add return type to method. As you posted you are returning String without giving return type of method. So add String as return type of method. If you try to return a value from a method that is declared void, you will get a compiler error. public String Tutor(String firstName, String lastName, String degreeLevel) { ..... return(lastName +", "+ firstName +" "+ degreeLevel); }
You're treating Tutor like a method. If Tutor is indeed a method, you don't have a return type associated with it. Also where are firstName, lastName, and degreeLevel getting declared at in the class? It looks to me like there maybe other issues than just that -- keep in mind.
Your code is really messed. You have a class named CalculateATutor, inside it something looks like a constructor but named Tutor and you use it inside your main function as a regular class. First, you need to understand what you want to do (and maybe read about classes and constructors). But for your question: If you want to have a method named Tutor, you need to add return type to the method signature; public String Tutor(String firstName, String lastName, String degreeLevel) { this.firstName = firstName; this.lastName = lastName; this.degreeLevel = degreeLevel; return(lastName +", "+ firstName +" "+ degreeLevel); } If you're trying to create a constructor, you need to use the class name and remove the return statement: public CalculateATutor(String firstName, String lastName, String degreeLevel) { this.firstName = firstName; this.lastName = lastName; this.degreeLevel = degreeLevel; }
Your Tutor method is returning a string, but you haven't declared it as having a return type. Try: public String Tutor(String firstName, String lastName, String degreeLevel)
It's not clear if Tutor is supposed to be a method or a constructor. If it is supposed to be a constructor, you are declaring it in a class named CalculateATutor, which won't work. You also did not write the constructor as a constructor (it should not have a return statement). You can fix this in several ways: Change the class name to Tutor. Change the constructor name to CalculateATutor. Move the Tutor constructor to an inner class of CalculateATutor named Tutor.
1) you're using the this. keywork to refer to class variables that you haven't defined 2) you seem to have called the class CalculateATutor but the constructor for the class Tutor, they should be the same, so something like this: import javax.swing.*; public class Tutor //NOTE CORRECTED CLASS NAME { String firstName; String lastName; String degreeLevel public Tutor(String firstName, String lastName, String degreeLevel) { this.firstName = firstName; this.lastName = lastName; this.degreeLevel = degreeLevel; } public static void main (String[] args) { String ans; List<Tutor> Tutor = new ArrayList<>(); for (int i = 0; i<Tutor.size; i++) //Tutor.size==0, will never run, I can't correct as I have no idea what you want to happen { ans = JOptionPane.showInputDialog(null,"Enter Tutor's Last Name, First Name, and Highest Level of Degree:"); Tutor = ans; //I have no idea whats going on here but Tutor should be initialised like new Tutor(string,string,string) } } }
Unable to display object array using get(index)
I am trying to display the different objects in an ArrayList. In my project context, one student is one object. I used an ArrayList to store all the different student objects and I am having problems reading the ArrayList. <% String student_name = request.getParameter("studentName"); ArrayList<Object[]> studentList = new ArrayList<Object[]>(); if(student_name != null && student_name.length() > 0) { PreparedStatement preparedStatement = con.prepareStatement("Select * from users where firstname LIKE ? "); preparedStatement.setString(1, "%" +student_name+ "%"); ResultSet resultSet = preparedStatement.executeQuery(); while (resultSet.next()) { String first_name = resultSet.getString("firstname"); String last_name = resultSet.getString("lastname"); String email = resultSet.getString("email"); Object[] student = {first_name,last_name,email}; studentList.add(student); session.setAttribute("studentObject",studentList); //System.out.println("First Name: " + first_name + "," + "Last Name: " + last_name); System.out.println(studentList.get(0)); } When I try to display (studentList.get(0)), all I see is "[Ljava.lang.String;#XXXX" How do i get it to display the different student objects based on the index ?
At first, It will be more idiomatic in Java to define your own class Student. Write an extractor to that class, define toString method and it will be great. Java requires you to define toString method to any type of object that will be printed. So, you have to define toString for your Student class. But you are using an array. Java doesn't have toString method defined for Arrays. So I would propose you to do something like this. (I'm a bit on rush so code may contain some mistakes: // At first it could be better to define a structure // that represents a student // class must be defined in separate file like Student.java // Student.java public class Student { // constructor for the Student object public Student(final String firstName, final String lastName, final String email) { this.firstName = firstName; this.lastName = lastName; this.email = email; } private String firstName; private String lastName; private String email; #override String toString() { return firstName + " " + lastName + " " + email; } // getters public String getFirstName() { return firstName; } public String getLastName() { return lastName; } public String getEmail() { return email; } // setters public void setFirstName(final String firstName) { this.firstName = firstName; } public void setLastName(final String lastName) { this.lastName = lastName; } public void setEmail(final String email) { this.email = email; } } // end of Student.java file /////////////////////////////////////////// final ArrayList<Student> studentList = new ArrayList<Student>(); .... // your code ResultSet resultSet = preparedStatement.executeQuery(); while (resultSet.next()) { // creating a new student with new keyword final Student currentStudent = new Student( resultSet.getString("firstname"), resultSet.getString("lastname"), resultSet.getString("email") ) // you are adding a student object to the list studentList.add(currentStudent); session.setAttribute("studentObject",studentList); // that should work // toString method will be called implicitly System.out.println(studentList.get(0)); } // So you will have a list of students // that will be accessable in the following manner: studentList.get(0).getFirstName; studentList.get(1).setFirstName("New name"); If you want a different behaviour you may call those fields directly, or modify the behavior of toString method Java also assumes that you're using camelCase notation, you may find in in the style guide. Hope it helps.
Try java.util.Arrays class: System.out.println(Arrays.toString(studentList.get(0)));
Currently you are printing out the Object[] which is not exactly human readable. I would suggest creating a new class called Student. Then have three member variables firstName, lastName, and email. Also create a toString() method for this new class. Then you can have an ArrayList of Students. This should simplify everything for you.
You have at least two options: Implement an object corresponding to Object[] student: In this class you may override Object's toString(), and implement it as to wish to present the data. NOTE: this is very relevant to you because when printing studentList.get(0) you actually print call Object's default toString() which returns the reference to the object. For more information regarding default Object.toString() here. The simplestway is to use Arrays.toString(): System.out.println(Arrays.toString(studentList.get(0)));
It looks like you're not trying to display a String as you expect, you're trying to display an array of Objects. You could try : System.out.println(studentList.get(0)[0]); You'll have an idea
JAVA - HELP adding comparable interface and arrays into my class
I got a lab assignment dealing with arrays, sorting them and adding comparable interface to my two classes. I have to modify a Customer class so it implements a comparable interface. Then I have to sort an array of objects created by this class. These are the steps outlined by my worksheet: open the customer and SortedCustomersApp java files (see below): public class Customer { private String email; private String firstName; private String lastName; public Customer(String email, String firstName, String lastName) { this.email = email; this.firstName = firstName; this.lastName = last; } } This is the sorted customers app: import java.util.Arrays; public class SortedCustomersApp { public static void main(String[] args) { } } add code to the customer class to implement the comparable interface. The compareTo method you create should compare the email field of the current customer with the email field of another customer. To do that you cant use the < or > operators because the email field is a string. Instead, use the compareToIgnoreCase method of the string class. This method compares the string it's executed on with the string that's passed to it as an argument. If the first string is less than the 2nd string, this methods returns a negative integer. if the first string is greater than the second string, it returns a positive integer. And if the 2 strings are equal, it returns 0. 3.Add code to the SortedCustomersApp class that creates an array of Customer objects that can hold 3 elements, and create and assign Customer objects to those elements. Be sure that the email values you assign to the objects aren't in alphabetical order. Sort the array. code a "for each" loop that prints the email, firstName, and lastName fields of each Customer object on a separate line. compile and test the program This program needs to have user input for email, firstName, and lastName but when I tried adding user input to the customer app I got errors saying I cant convert a string to scanner type, but the user inputs need to be a string so that's also a problem.
you implement Comaprable in order to define for Collections.sort() what criteria you use compare instances.For example if I was to compare students by their grades: public class Student implements Comparable<Student>{ int age; int grade; //this method is used in Collections.sort() to determine what is bigger //for me its grades that matter so that's what I do in code #override compareTo(Student other){ if(this.grade>other.grade){ return 1; }else if(grade<other.grade){ return -1; } return 0; } } then you just create an ArrayList students for example and call Collections.sort(students) EDIT: to answer you question in comments. If you use a Collection like ArrayList you would call Collections.sort() , if you use a regular array, then Arrays.sort(). In both cases the Objects to be sorted need to implement Comparable just like I showed you.
You can compare two String's lexicographically calling compareTo method on String object, code looks like this public class Customer implements Comparable<Customer>{ private String email; public Customer(String email) { this.email = email; } public void setEmail(String email) { this.email = email; } public String getEmail() { return email; } #Override public int compareTo(Customer otherCustomer) { return this.email.compareToIgnoreCase(otherCustomer.email); } #Override public String toString() { return "Customer{" + "email='" + email + '\'' + '}'; } } You can sort list of objects using Collections.sort method List<Customer> list = new ArrayList<>(); list.add(new Customer("abc#bc.com")); list.add(new Customer("des#bc.com")); list.add(new Customer("bbc#bc.com")); list.add(new Customer("aec#bc.com")); Collections.sort(list);
modified customer class public class Customer implements Comparable<Customer>{ : public int compareTo(Object obj) { Customer cus = (Customer) obj; // write your comparison code here // return 1, 0, or -1 on the basis of your requirement } : } Then perform Collection.sort(customerList); in main method to sort the data. There is two ways to take String as an input from user: 1) Buffered Reader BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); String email = reader.readLine(); // email, firstname etc. 2) Scanner Class Scanner input = new Scanner(System.in); String email = input.next(); Now create an Customer object and add setter method to set the value.
Why won't this print anything but null?
Why won't this print anything but null? I am attempting to add new objects that are created as you answer the question and then add them to an array which I can access at a later time. public static void main(String[] args) { // TODO code application logic here addastudent(); } private static void addastudent(){ ArrayList<Object> students = new <Object> ArrayList(); Scanner user = new Scanner(System.in); System.out.println("First Name: " ); String fname = user.next(); System.out.println("Last Name: "); String lname = user.next(); System.out.println("Major: "); String major = user.next(); System.out.println("GPA: "); double gpa = user.nextDouble(); student a = new student (fname,lname,major,gpa); students.add(a); System.out.println(students); } Edit: Thank you for pointing out the toString() problem. That was it. I had forgot I told the toString() to return Null. I hate it when you miss something that simple... Thanks guys again
There are several problematic items in this code. You should overwrite toString in the Student class. Otherwise it will use toString of Object, which will print something like "Student#148ccb8". Ensure the constructor of Student assigns all its field with the given parameters. You didn't provide the code, but it should look something like this: public class Student { private String firstname; private String lastname; private String major; private double gpa; public Student( String firstname, String lastname, String major, double gpa) { this.firstname = firstname; this.lastname = lastname; this.major = major; this.gpa = gpa; } #Override public String toString() { return "Student [firstname=" + firstname + ", lastname=" + lastname + ", major=" + major + ", gpa=" + gpa + "]"; } } And some minors: Class names in Java should start with a capital letter. So it's Student and not student. Creating an ArrayList for when creating a single Student instance is not appropiate (yet), but makes sense when you extend the code to severeal Student instances. Using generics with Object is not using them at all! When using Collection classes, usually declare your variable to the common supertype. With the last two points it's: List<Student> students = new <Student>ArrayList();
Change ArrayList<Object> students = new <Object> ArrayList(); To ArrayList<student> students = new ArrayList<student>(); Add overided toString method in Student class. Hint! If you are using eclipse IDE then select your student class and go to Source menu and select generate toString method from there.
First of all, please follow Java Naming Conventions and rename your method to addStudent, also please change student class to Student. In this line, ArrayList<Object> students = new <Object> ArrayList(); you're creating an ArrayList object, which's called students, Object is very generic, try to be more specific and change it to: ArrayList<Student> students = new <> ArrayList(); Finally, you're printing the object, and not the content. In order to print the content, you need to iterate on students array list and print each object, after you override equals in Student class.
If that is the full code the issue is that you have no student class. In order to use the student class you have to tell your program what it is. Here is a simple student class to start you off. public class Student { private String fname; private String lname; private String major; private double gpa; public Student(String fname, String lname, String major, double gpa) { this.fname = fname; this.lname = lname; this.major = major; this.gpa = gpa; } } I haven't compiled this code but it looks like it should work. NOTE: You will need to change new student (fname,lname,major,gpa); to new Student (fname,lname,major,gpa); (Notice the case change)
students variable (ArrayList) should be an instance variable, not local variable. According to above code, you will always end up with only single student in the list because you re-create the ArrayList each time when the method addastudent is called.
How to load an ArrayList with instances of an Object I created
NOTE: I edited my code to how I think people are trying to tell me but it still doesn't give me my desired output. Now my output is "examples.search.Person#55acc1c2" however many times I enter new first and last names. At least it's making it through the code with out crashing lol I am learning how to use ArrayLists and need to load an Array list with instances of an Object I created. I know how to do this with an array but for this assignment I need to do it with an ArrayList. Here's an example of what I need to do. // my "main" class package examples.search; import java.util.ArrayList; import dmit104.Util; public class MyPeople { public static void main(String[] args) { ArrayList<Person> people = new ArrayList<Person>(); Person tempPerson = new Person(); String firstName; String lastName; char choice = 'y'; int count = 1; // fill my ArrayList do { people.add(tempPerson); // I have a Util class that has a prompt method in it firstName = Util.prompt("Enter First Name: "); lastName = Util.prompt("Enter Last Name: "); tempPerson.setFirstName(firstName); tempPerson.setLastName(lastName); count++; choice = Util.prompt( "Enter another person? [y or n]: ") .toLowerCase().charAt(0); } while (choice == 'y'); // display my list of people for(int i = 0; i < people.size(); i += 1) { System.out.print(people.get(i)); } } } // my Person class which I am trying to build from public class Person { // instance variables private String firstName; private String lastName; // default constructor public Person() { } public String getFirstName(){ return firstName; } public void setFirstName(String firstName) { this.firstName = firstName; } public String getLastName() { return lastName; } public void setLastName(String lastName) { this.lastName = lastName; } } I've tried it a number of ways but no matter what my ArrayList doesn't fill up. Like I mentioned I can do it no problem with an array or even if I had a loaded constructor method but I don't. In my actual assignment I am supposed to do it with the set methods. I have looked everywhere and cannot find the solution for my problem and being friday my instructor isn't in. Thank you so much in advance Leo
You have an ArrayList<Person>, but that alone only defines a list of potential Person instances. But so far, each of the list entries is null. The get(i) returns null, and the following null.setFirstName(..) causes a NullPointerException. So you need to create the instances of Person that are supposed to go into the list: firstName = Util.prompt("Enter First Name: "); Person p = new Person(); //create the instance people.add(p); //add the instance to the list p.setFirstName("..."); //set any values
You'll have to create a Person and then add it to the ArrayList. for (int i = 0; i < count; i++) { Person person = new Person(); person.setFirstName("Foo"); person.setLastName("Bar"); people.add(person); }
Its crashing because your line people.get(i).setFirstName(firstName); is first trying to what is at index i, but you have not set anything yet. Either first set people[i] to a empty Person, or make a person using firstName and lastName, and add it to people using people.add(person);
Now you are storing the Person Object into an ArrayList and printing that Object. To print the firstname and lastName when you print the Person object, you will have to override toString method. Add the following code in your Person class public String toString(){ return String.format("[Personn: firstName:%s ,lastName: %s]", firstName,lastName); }
As for the second question you had, you have to override the toString() method in the Person class. The outputs you are getting, such as examples.search.Person#55acc1c2 is the default toString() method from the Object class, which is defined as class#hashCode | https://java.develop-bugs.com/article/10000160/Print+ArrayList+from+another+Class | CC-MAIN-2021-21 | refinedweb | 4,205 | 57.27 |
program does not somewhere allocate and deallocate a little memory thousands of times, which can cause this issue. Alternately, download and run a freeware program called rambooster, I think this may help. The best fix is not to use dynamic memory anywhere you don't have to (won't fit on the stack, or other reasons like run time determined size, etc).
If you truely do run out of memory, the "beyone dual processor" versions of windows (2k and/or xp?) can have more than 2gb memory, somewhat more expensive).
Also, what do you mean "make sure the program takes advantage of the full memory available" ??? Do you want to query the OS to find out how much memory is installed, and allocate a fixed percentage of it?
if nebeke is correct, then you have a problem. 2bg of memory is a whole LOT of memory. unless you are processing a very long segment of a graphical input, and I mean hours worth of input, You have a memory leak in your program.
your source code might help
Protecting your business doesn’t have to mean sifting through endless alerts and notifications. With WatchGuard Total Security Suite, you can feel confident that your business is secure, meaning you can get back to the things that have been sitting on your to-do list.
There are no efficiencies gained by using "new" vs. malloc, unless you intend on writing your own new handler....
Posting code will be a problem - its a pretty large program, that has been "evolving" some time now, worked on by several people in the academy (you get the picture).
I don't have the exact numbers (how much mem exactly I'm trying to allocate) but I know its way less than what I have. This since calloc fails when I try to allocate memory to copy a certain array. The new array is as large as the existing one. Task manager tells me I still have way memory left, but it still fails.
Anything?
Cann't you send some information for hard-disk?
If nebeker is correct, did you see how many Virtual Memory you are using?
oleber : Have around 5gig swap file. I think that should be enough for my needs.
makerp : I'll have to try that but it'll take me time. Will get back to you on that today-tomorrow.
I understand that there is no general known issue with memory limitations, right? There is no hidden switch labeled "let me use everything you got" that I haven't been pushing?
Hmm... I had wild idea. Try to allocate memory with CreateFileMapping.
The maximum physical addressing space is 4GB in 386 protected mode.
C code:
/* an example */
#include <stdlib.h>
#include <stdio.h>
int main()
{
void *largeP;
unsigned int uSize; /* unsigned int is 4bytes(32-bit) in VC++6.0 */
uSize = 0x80000000 - 1; /* 2G-1 */
largeP = malloc( uSize );
if( largeP == NULL )
{
printf("Ok");
free( largeP );
}
else
printf("Falied");
return 0;
}
Doesn't malloc use heap not stack?
Thanks all,
Frost | https://www.experts-exchange.com/questions/20329223/Huge-memory-requirments.html | CC-MAIN-2018-26 | refinedweb | 508 | 74.29 |
Agenda
See also: IRC log
<trackbot> Date: 11 March 2009
<Bob> good morning
<Bob> We are working on the phone
<li> hi everyone
<Bob> we have audio
<Bob> scribe: Vikas
<DaveS> Good morning
Asir: Use CVS notification for a checkin...to review.
<dug> for some reason why cvs won't send in my cvs update comments
<Yves> also I can make a snapshot at a specific location, easy to do
<dug> well, just doing a cvs diff by date works too
Asir: Use CVS labels and compute automatic diff.
<Yves> yes, we could do a "make snapshot" "make tags" etc...
<asir> what about a diff version
Bob: make a snapshot once a
month.
... Asir help the editors to compute the diffs
<Yves> there should be a diffspec.xsl as well
<Yves> is indeed only for bugzilla now, I can make it extended to add cvs commits
<scribe> ACTION: Yves, notification setups [recorded in]
<trackbot> Sorry, couldn't find user - Yves,
<scribe> ACTION: Yves notification setups [recorded in]
<trackbot> Created ACTION-38 - Notification setups [on Yves Lafon - due 2009-03-18].
The working group agrees for monthly review of snapshots.
Asir: Sugegst to have summary of change logged at bottom of spec.
s/sugegst/suggest
Resolution: Add change log at bottom of each spec.
Bob: Executive summary of changes log for public?
Dug: Who will maintain it?
Bob: Look into the executive
summary option later.
... First snapshot review - April 1st
Resolution: First snapshot review - April 1st.
<Bob> Revisit 6400 due to request for overnight review
<Bob> proposal at
Li: Change subscription & port to Subscription & Porttype.
<li> change SubscriptionEndPort to SubscriptionEndPortType
Resolution: change SubscriptionEndPort to SubscriptionEndPortType
6400 resolved.
Geoff: Proposed close with no action
Dug: Want to keep GetMetadataResponse for consistency across spec.
<li> EndTo endpoint cannot use wrap interface to receive SubscriptionEnd message because it is a protocol message, not an event message
<dug> <mex:GetMetadataResponse ...>
<dug> <mex:MetadataSection...> ... </mex:MetadataSection> *
<dug> xs:any *
<dug> </mex:GetMetadataResponse>
<Bob> For minutes edit, move Li's comment above start of issue-6500 discussion
Alternative proposal by Dug above
<Bob> It was noted that extensibility is already in the schema, but not in the text
<Bob> Dug: In that case it gets down to just re-naming the element
Daves, Asir asking for use cases.
<Bob> Dave: What are the use-cases for extending the response?
Katy: Don't rename mex:metadata.
<dug> Katy: go back to original proposal
Bob: Any objection to the proposal.
Geoff: Object, 6398 need to be looked at first.
Gil: No need to add dependency on 6398.
Bob: Any objection on the new proposal.
Geoff, Asir object, asking for more time
Doug Ashok : How much time is required.
Dug: Agains adding dependency of 6398 in 6500.
Gil: Time line to put forward formal objection for 6398?
Bob: Will look at 6500 later.
<Katy>
<Yves> why defining Dialect as an attribute and not as a child element of wst:GET ?
<Katy>
<dug> yves - could be done that way - but there some concern from MSFT folks when we first worked on that they wanted to be able to detect an unknown dialect asap and an attribute was easier than going down one level.
<Yves> dug - what is the namespace of Dialect attribute then? having a wstr:dialect element sounds easier as an extension point than adding an attribute in wst: everytime you want to do such add-on
<dug> well, since we believe that RT will be fundamental to T's use it makes sense to have it part of the same namespace
Geoff: Why are we doing it, as of now there are no issues raised regarding WS-Transfer and WS-RT complexity.
Dug: WS-RT only makes sense in presence of WS-Transfer.
<Bob> Dug argues (amongst other things), that RT reduces the need for transactional support, since it would reduce collisions
<Bob> Dave: If they were written together then the inconsistencies would be resolved, but then ought to be split
<DaveS> 1) Generally splitting is better.
<DaveS> But:
<DaveS> 2) Consistency is needed between Tx and RT. Merging will fix these.
<DaveS> 3) Prevention of rouge extensions that duplicate RT function.
<DaveS> 4) Interaction semantics between the two capabilities is more transparent.
<DaveS> 5) Encourage wider uptake of the full capability of Tx + RT.
<DaveS> - Develop together and the split
<DaveS> - Restrict transfer as we split them so as to capture semantic interaction,
<Zakim> asir, you wanted to talk about the history
<Wu> "<DaveS> - Develop together and the split" - Do you mean "Develop together and then split"
Asir: -Duplication, overlap, needs to be handled on case-by-case bases.
<DaveS> yes: Develop the specs together to clarify semantics, overlap, common issues. Then split if the result really looks to complex.
<Bob> ac bob
Bob: Against fully merging the two spec.
<Katy> Adding to Dave's list above
<Katy> 6) From Editorial and WG point of consolidating proposals across the 2 specs is far easier (wrt time and effort) when they are merged
<Yves> is dialect fragment or conneg?
<dug> http has fragment support
<Bob> http frags are a user agent function
<Zakim> asir, you wanted to respond to Doug
<Zakim> Yves, you wanted to say is dialect fragment or conneg?
<dug> +1 to yves - transfer is missing a ton of http features
<asir> +1 to Yves for using SOAP extensions
<asir> that is what Resource Transfer does today
Katy: IBM has implementation of WS-RT.
<Geoff> +1 to dug for RT not being as mature at T
<dug> bob - I was referring to the http range headers not the user-agent stuff
<Katy> My comment was: we were reluctant to implement rt due to bp compliance issues with the wst base spec
Daves: Obligation of smooth transpiration for present implementation.
<Yves> if it is a fragment, should it be part of the EPR?
Bob: Important consideration
1 - Common stuff should be commonly defined.
2- RT Fragments, is an extension; is it a common operation; is it a optional operation.
3- Some RT Features have questions, problems, unclear, broken
<Geoff> is the value of doing this work, greater than the amount of work required to achieve it?
Bob: Do the working group consider frags as extension.
<scribe> ACTION: Katy produce a document on frag support as an extension. [recorded in]
<trackbot> Created ACTION-39 - Produce a document on frag support as an extension. [on Katy Warr - due 2009-03-18].
<fmaciel> ok
<Bob> we are re-starting
<asir> I promised to add my statements on 6413 to the IRC
<asir> here it is
<asir> If there are any overlap between T and RT, those should be identified as separate issues and resolved
<asir> If there are any duplication between T and RT, those should be identified as separate issues and resolved
<asir> If there are any inconsitencies between T and RT, those should eb identified as separate isseus and resolved
<asir> if any of the current RT issues apply to Transfer, the WG will address them across specs
<asir> We acknowledge the 2 possible cases - simple use case and non-simple use case. We have seen umpteen impls of the simple use case and we have plenty of interop evidence. We do not not seen any implementations of the non-simple use case.
<asir> If any of the RT issues (filed by Microsoft) apply to Transfer then the WG would consider that and address it as well. This is similar to how the WG processed 6428 against Eventing whose resolution was applied to all 5 specifications
<asir> Re bunding specs will increase market adoption and interop - this is a myth. Market adopts value not required and optional features. Bundling is not the solution
<asir> Re WS-Man created a domain specific fragment transfer - RT was born in 2006. WS-Man was born in 2002. It is common for a feature to be born in a domain specific way and then promoted in a generic manner at a later date
<asir> RT did not carry the consensus of the authors during its dev and submission (only IBM and Intel submitted, Microsoft and HP did not).
<asir> There wasn't consensus to add RT to the charter ...
<asir> RT frag transfer is an extension of Transfer (from the SOAP Processing Model point of view)
<asir> In order to not burden current dependant specs on Transfer we believe that the extension should be in a separate specification
<Bob> scribe: Katy
Asir: Ashok polinted out may not
get response for tag
... from tag
... Bob suggested waiting to last call
... we are concerned about time and following the Tag discussion
... What we could do is put each issue in bugzilla and consider proactively addressing each of the issues
... then Bob could take these issues to the tag
... We volunteer to get these issues out and propose draft resolutions
Ashok: There are 2 issues 1) why
WS use EPRs rather than URIs? What answer should we give?
... 2) We could consider what does a naked HTTP GET on the URI return?
Gil: Think we should address any issues at LC and not pre-empt
DaveS: Don't want unecessary energy spent on this.
Asir: Understood, concerned about potential blocking issue
Bob: Being prepared is good. I am
hearing mixed discussions regarding how much preemptive work
should be done
... If we use the issue process (this is public and debated and requires closure before last call).
... These are not proper issues - other ways to approach
DaveS: We can prepare a document
and discuss at next F2F
... I will work with you on this.
Ashok: Issues in a WG are opened against documents, what would these issues be opened against
Asir: WS-T (2) and WS-RT (1)
Ashok: What could we say here
Asir: We could say: for 1st
issue: This has been considered by the ws-ra working group and
this is what we have decieded (unified voice)
... for 2 propose: SOAP response pattern binding to HTTP GET
<Yves> see
<scribe> ACTION: Asir/Dave to collaborate on a discussion document about how to proceed [recorded in]
<trackbot> Sorry, couldn't find user - Asir/Dave
<scribe> ACTION: Asir and DaveS to collaborate on a discussion document about how to proceed [recorded in]
<trackbot> Created ACTION-40 - And DaveS to collaborate on a discussion document about how to proceed [on Asir Vedamuthu - due 2009-03-18].
Dug: Propose same solution that we accepted for WS-Eventing subscription end
<dug> proposal:
<dug> and change EnumEndPort to EnumEndPortType
Bob: no objects
RESOLUTION: 6399 resolved
<dug> proposal:
<dug> an amendment:
Gil: described issue
... Dealing with filters that will never evaluate to true - event sources should try to indicate this
Geoff: As Doug said, we need to ensure that it is clear that the generation of this fault is only at subscribe time
Wu: Concerned that the client may use this to test what the event source supports - interop issues
Gil: This is for simple situations where the filter is easily understood
<Bob> It is possible for the request to contain a filter that will not evaluate to true for the lifetime of the Subscription. Although this condition cannot be detected for all dialects, implementers are advised to check for it when possible and, in response to the Subscribe request message, OPTIONALLY to a Subscribe request
<Bob> message generate a wse:EmptyFilter fault.
<dug> It is possible for the Subscribe request to contain a filter that will not evaluate to true for the lifetime of the Subscription. Although this condition might not always be detectable, implementers are advised to check for it when possible and, in response to a Subscribe request message, OPTIONALLY, generate a wse:EmptyFilter fault.
Wu: not sure about 'impls advised to check for this'
Gil: It is just advice
Wu: But this is not preferred
Li: I recognise that this is a very annoying situation but it's hard to imagine how implementations could check this - e.g. xpath
Gil: This is intended for filter
dialects with finite values. Just when it's possible. Impls
could do basic checks
... A key thing is to advise subscribers that an extra fault could be gen'd when it is clear that there will never be notification messages
Wu: I am concerned with wording still - 'advised' text
<scribe> ACTION: Gil work with Wu on text for 6595 [recorded in]
<trackbot> Sorry, couldn't find user - Gil
<scribe> ACTION: gpilz work with Wu on text for 6595 [recorded in]
<trackbot> Created ACTION-41 - Work with Wu on text for 6595 [on Gilbert Pilz - due 2009-03-18].
Gil: Outlined key aspects.
EventTypemsg in its own schema plus attribute
extensibility
... in wsdl dfn notifyEventMessage has hdr notify verb and body notify element
... in soap binding hdr part is bound to soaphdr and body bound to soap body
... Motivation was to put metadata in header. wse:NotifyVerb in header - tooling will expose this verb as a parameter
... for e.g. msg bus scenario
dug: This proposal splits the
service level data between the body and the headers
... This concerns me and I would like some time to discuss with implementation teams
... 1 week's delay
Wu: I propose separate this into 2 issues: 1 agree to have standard interface and separate issue of where to put the action
Geoff: Agreeing with Doug again! Would like time to consider also
gpi: we need crisp texts prior to closing this issue, this proposal is just the form
Wu: Let's close what we have decided and separate out a new action in order to deal with the extended proposal
Gil: The current proposal is not complete for incorporating into the document. Would be nice to have text describing when wrapped would be good.
Wu: Explanationary text should be in primer
Gil: reference to format in appendix would help
Wu: we can create text changes
<gpilz> other probs with current text for 6429: (a) text discusses including the "concrete WSDL" in wse:NotifyTo, how is this done?
<scribe> ACTION: Wu to examine current spec and generate new text for group review [recorded in]
<trackbot> Created ACTION-42 - Examine current spec and generate new text for group review [on wu chou - due 2009-03-18].
Li: Could the verb be a ref param?
Gil: No because the notification type is a constant across the lifetime of the subscription
<gpilz> (b) text says "concrete WSDL can be retrieved by the Event Source use WS-MEX" how?
Li: Agree with Wu that we should close this issue and treat the enhancement as a sep one
Li: This is the proposal that treats the format as an element (rather than an attribute)
Dug: Would like to see text describing processing order - filter should be on unformated event
Wu: Agreed this is a good comment. Another issue though.
<scribe> ACTION: Dug to open a new issue for this [recorded in]
<trackbot> Created ACTION-43 - Open a new issue for this [on Doug Davis - due 2009-03-18].
Geoff: What if can't support format element
Dug: It is an optional element
that must be understood
... text decribes that the implied value is unwrapped
... must process or send a fault - not just ignore
Asir: It needs adding to migration path
<asir> migrationPathNeeded
<Yves> "The keyword migrationPathNeeded has been added."
<asir> All hail to the power of consensus!
RESOLUTION: 6428 is resolved
Li: Subscribe has authentication
and authorisation costs so overhead if you need to
unsubscribe/resubscribe
... 3 way handshake required
... pause and resume will reduce this cost
<Bob> Thanks, Yves!
Dug: On overflow do you retain
1st 5 or last 5
... for interop should specify
Dug: Consider adding a line one way and change it later if required?
Geoff: Do we need to discuss the value of adding pause and resume?
Wu: value of pause and resume is
highlighted in web services roadmap document (item 5)
... We think this is useful. I am sensitive to Geoff's comment so we could make this an optional feature
Dug: 2 things that should add to
proposal. 1) clarify whether buffering of msgs happens
before/after filtering
... 2) Retain parameter on pause and response. I would prefer the pause to fail if the request cannot be granted
Geoff: would like time to consider
<asir> perhaps, in another specification
Ashok: This is extra functionality, not fundamental to the core spec
DaveS: If client does not have pause/resubscribe then can it attain same function by unsubscribe/subscribe
<Bob> k
Wu: pause/resume is a short hand so does not break interop (as it's a shorthand for unsub/sub) but retain message number is not shorthand
gpilz: how would I know whether event source supported pause resume?
Dug: policies
Wu: this is optional
More time for decision requested
<scribe> ACTION: Li to address Doug's 3 concerns [recorded in]
<trackbot> Created ACTION-44 - Address Doug's 3 concerns [on Li Li - due 2009-03-18].
<Bob> break until 2:45 EDT
<dug> Li you there?
<li> msg dug yes
<dug> just saw your note - I'll reply to that
<li> msg dug thanks
RESOLUTION: 6498 Resolved as defined in proposal (editors update uri name)
Dug: Mex dialect=group of things
that service should return to client to indicate what's needed
for communication
... but what if the service has metadata that the client might need (but client doesn't know about)
... At extensibility to enable service to add this 'extra' metadata stuff
... on top of that add 'all' dialect
... then worry about default
Geoff: Our 'whateverdialect' = Doug's Mex dialect
<dug> 'whateva' used to mean "random - even zero"
Geoff: also think that there
should be a just mex dialect
... mex=the mex dialects
... whatever=the mex dialects plus optional extras
... mex=mex defined dialects crucial=mex plus other stuff that need to talk to service
gpilz: Should rename 'mex'
<gpilz> 'mex' should be renamed 'defined'
gpilz: Confusion is when a bag of dialects is named the same as a dialect itself
<gpilz> from smallest to largest (schema | wsdl | policy | policyAttacment), defined (set of previous), crucial (defined plus sections requester may not know about), all (everything available to the provider)
Dug: The 4 dialects in the metadata spec are fairly arbitrary. Also they can be gotton by separate requests. So the 'mex' (or 'defined') dialects is not much use.
<dug> none = mex = the stuff the services thinks the client needs to talk to it - minimum = tables in mex
<dug> all (new uri) = everything under the sun the client is allowed to see - ie. dialect=*
asir: Interop testing refer to proposal for 6420 (closed as dup of this one). This proposal talks about min
Dave: I like the idea that the
service knows what you need to talk to it
... eg if I don't need policy documents - why would I return them?
<marklittle> Hi Bob
<Bob> Hi
Dug: There's a difference between returning anything and what's required by the client to talk
<Bob> ?
<Bob> Katy requests time to conferr with the mothership
Katy: Concerned about the overlap
of these dialects - the same information may be passed back in
policy and wsdl dialects - a huge amount of data in
duplicate
... Puts great requirements on service and large data transfer
<Zakim> asir, you wanted to answer Katy's q
<DaveS> If we had only all and default (meaning what the service thinks the client needs), what interop or migration problems does this raise?
Ashok: Not clear where policy documents should be returned on receipt of policy dialect
Katy: policy and policy attachment dialact not clearly defined
Asir: Policy references give the
link to the policy documents
... policy dialect is not useful on its own but is useful in a wider exchange
Dug: concerned that we are overengineering and will confuse people
<asir> well .. at the discretion of a provider .. you may or may not return duplicates
Dug: no longer a for-loop service needs to interpret
<asir> other specifications may define these dialects ..
Geoff: Don't let us forget the key issue - the communication bootstrap 'what do I need to talk to you'
<asir> but for the standards that have already sailed and relevant to WS should be specified in this doc
gpilz: just two different things 1) individual dialacts and 2) bootstrap info
bob: we need to write up and
understand
... few primer words to describe expected usage
... (primer like - might be doesn't need to be in primer)
katy: Issue for describing dialect uri's
s/uris/uri's
bob: The critical set is what the provider needs to communicate?
consensus to this.
bob: do we agree that 'all' is useful?
dug: Use case metadata browser
ashok: or another non-specified dialect (e.g. legal)
consensus
bob: is it true that a provider can provide optimisation?
consensus to this.
bob: Waht about the current 'mex'
which is a subset of all?
... do we need to define this piece called 'mex'?
<asir> that was awesome Bob!
<dug> none==critical, all=all, allow for list of dialects
<Bob> Agreement:
<Bob> no dialect == everything that the provider considers important with the ability to optimize
<Bob> dialect="ALL" == all known metadata with ability to optimize
<Bob> one can specify a dialect list on the getmetaadatarequest
RESOLUTION: issue 6404 resolved
Geoff: This may no longer be
valid now that we are specifying the format
... But clarifies if the (optional) content is not there, then the service decides
Dug: Is this a duplicate?
Asir: it's superceded by another issue
RESOLUTION: superceded by 6405, no editorial action required. Issue closed.
Yves: Part of semantic alignment between http and transfer. Work out whether you can retry a request
asir: concerned that the contents of the table is not there - i.e. for each operation state what is safe and what is not
<asir> also we need to see the wording from RFC 2616
<Yves> proposal is getting inspiration from
<asir> agree .. suggest that we prep a concrete proposal prior to closing
Dug: clarification required. Yves - is there something in the spec that would lead you to believe that the transfer get is not safe?
Yves: The spec says nothing so it is not clear.
Bob: and proposal was inspired by RFC 2616
Dug: The spec already implies to me that there is no side effects to a get. What is broken?
Yves: Nothing broken, would just like this explicitly stated
<asir>
Asir: proposal above
<Yves> after a first delete, you may have an error, but in both cases the resource won't be there ;)
<Yves> but it would be abusive to say that the second delete would result in an operation on a resource
<Yves>
Asir: Should steal 2616 def - Get is idempotent and safe; put and delete are idempotent
<Yves> "A sequence that never has side effects is idempotent, by definition
<Yves> so doing nothing on a second delete is idempotent
<Bob> +1 Yves
Dug: I agree that we should have the table and as an editor would like the whole text so can just cut-and-paste
<scribe> ACTION: Yves to create red-line text for this issue [recorded in]
<trackbot> Created ACTION-45 - Create red-line text for this issue [on Yves Lafon - due 2009-03-18].
<Geoff> thanks everyone, thanks Bob and host IBM, signing off now...
<asir> +1
Geoff and Asir request time to think.
<Bob> short break
<dug>
<Ashok> This document is also available in these non-normative formats: XML, XHTML with visible change markup, Independent copy of the schema for schema documents, A schema for built-in datatypes only, in a separate namespace, and Independent copy of the DTD for schema documents. See also translations.
<Ashok>
<Yves>
<Yves> is the best play to find out
Dug: propose namespace still
points to rddl, rddl points to everything, end of spec
reference to xsd is a direct uri
... (as in proposal above)
RESOLUTION: Resolved 6641 as described
bob: Request everyone checks IRC minutes for corrections/modifications/ommissions
This is scribe.perl Revision: 1.133 of Date: 2008/01/18 18:48:51 Check for newer version at Guessing input format: RRSAgent_Text_Format (score 1.00) Succeeded: s/snapshort/snapshot/ FAILED: s/sugegst/suggest/ Succeeded: s/Ty;e/Type/ Succeeded: s/SubscriptionEndPortTye/SubscriptionEndPortType/ Succeeded: s/Fof/For/ Succeeded: s/Aris/Asir/ Succeeded: s/issue/issues/ Succeeded: s/that/the/ Succeeded: s/born in 2004/born in 2002/ Succeeded: s/in response/in response to the Subscribe request message/ Succeeded: s/discussion/decision/ Succeeded: s/the provider/a provider/ Succeeded: s/shuld/should/ FAILED: s/uris/uri's/ Succeeded: s/6420/6404/ Found Scribe: Vikas Inferring ScribeNick: Vikas Found Scribe: Katy Inferring ScribeNick: Katy Scribes: Vikas, Katy ScribeNicks: Vikas, Katy Default Present: Yves, Li, [IBM], fmaciel Present: Yves Li [IBM] fmaciel Agenda: WARNING: No meeting chair found! You should specify the meeting chair like this: <dbooth> Chair: dbooth Found Date: 11 Mar 2009 Guessing minutes URL: People with action items: asir dave daves dug gil gpilz katy li wu yves[End of scribe.perl diagnostic output] | http://www.w3.org/2009/03/11-ws-ra-minutes.html | CC-MAIN-2013-48 | refinedweb | 4,166 | 57.61 |
As with all men and many cats, I derive particular pleasure from having my back scratched. When I say “particular pleasure”, I mean that I am absolutely crazy for it. I just can’t get enough of it. Unfortunately, it is very tiresome for the person doing the scratching, so I never could get anyone to last very long. Even my girlfriend’s valiant efforts have been woefully inadequate.
When I realized that no person would indulge my odd fetish without costing me extraneous sums of money, I did what any reasonable man would. I decided to build my very own robot minion to do my bidding. My bidding, of course, was that my back was to be tirelessly and ceaselessly scratched. It was obvious that the easiest and best way to do this was with my trusty LEGO Mindstorms kit, which I hadn’t touched until then, due to a distinct lack of imagination.
Immediately, I set forth to design the hardware of my robot sidekick. Many designs went through my head, from “robotic arm” to “creepy crawling robot” to “full-size android”. However, I only had the bricks that came with the Mindstorms kit, three servos, a few sensors and didn’t want any backtalk, so most of the designs were right out. The designs that seemed the most reasonable were two.
The candidate designs
One was the arm, which would have two points of rotation at the base, one to rotate the arm left and right, and one to rotate it up and down (azimuth and altitude, for those of you who have no idea what I meant), and would probably not really cover my entire back, would require stabilization so as not to fall over, and would require a few bricks too many. The second design that came to mind was a plotter-like design, with a square within which an object would be moved, and which could address a Cartesian plane, i.e. could move to any
(x, y) point specified.
I was going to go with the arm, but the design sounded tedious, so I delayed working on it. Then, one day, a new design came to me in a dream, Kekule-style! I dreamt of three coplanar spheres, touching each other and intersecting at a single point (okay, two, but I only needed the one). Immediately, I woke up, hastily scribbled “note to self: dream of more interesting things” on the notepad I always keep by my bed for occasions like these, and went back to sleep.
The three spheres that intersected at a single point was a rather elegant design for this problem. It would require a frame that was an equilateral triangle, one servo at each edge of the triangle (to serve as the centers of the spheres), and a piece of string on each servo, like a winch, that served as the radius of each sphere. The three strings would be tied together at the bottom, and by varying the lengths of the string (and thus the radii of the three spheres), any point in space could be addressed, and the scratcher could move anywhere on my back, if the triangle were large enough.
Building the design
This design had everything: It was very simple to build, required only three servos (which is exactly the number of servos in my disposal, how serendipitous!), was very simple to work with, and could address any point in space, within and below the confines of the triangle. A few minutes later, I had come up with an early prototype that worked rather well:
Some obvious improvements would be to take the servos away from the edges, put them in the middle and spool the string to the edges, to make the arms bear less stress (the servos are rather heavy). This design, as you can see, needs to be hung from above, as you can’t have anything below it or the scratcher won’t be able to move freely in space. Another improvement is to run the string through a hole in the LEGO girders, to avoid it unspooling from the edges of the winch or failing to spool back.
The build was generally very easy, I used two “thin wheel” (I’m sorry, I don’t know the LEGO part names) parts to get the desired angles on the triangle, and the rims of a dune buggy design for the winch. As I was looking for a way to affix the string to the rim so that it wouldn’t move, I noticed a small hole going from the outside of the rim to the inside, which was ideal for passing a string through. Knotting the string a few times on the other side made sure it would not come loose. I don’t know if that’s what that hole is for, but I can’t imagine any other use (wait, I just imagined one: It’s for getting air out of the tyres if you press on them). Regardless, it was a lucky discovery and I thanked my stars for it.
With the hardware ready, it was time to move on to the software.
Writing the controller software
To write the software, there were two main choices: I could either write it in a language that would run on the brick itself (such as NXC, which is a variant of C, or Java, which required flashing custom firmware on the brick), or I could write it on the PC and use a library that controlled the brick from it. I decided to go with the latter first, as there’s a very good Python library available for this purpose, called nxt-python. This would enable me to quickly prototype something and perhaps rewrite it to run on the brick at a later time.
For my purposes, it was clear that I needed to address the space in Cartesian coordinates (it would be easier to keep the scratcher on the same horizontal plane this way by just having
z be constant), which meant that I needed to convert triplets of string lengths (or radii) to Cartesian coordinates, and vice-versa. Luckily, Wikipedia has a very good article on this process, which is called Trilateration (it’s the equivalent of triangulation, but with radii rather than angles). Conveniently, the article contains equations for converting between the two systems both ways.
Converting the equations to Python was trivial:
# Servo A is at 0, 0, 0 # Servo B is at 0, D, 0 # Servo C is at I, J, 0 # Or, D is the length of a side of the triangle in cm. D = 32.0 I = D / 2 J = 0.86 * D def radii_to_cartesian(r1, r2, r3): """Use trilateration to convert cartesian coordinates to radii.""" x = (r1 ** 2 - r2 ** 2 + D ** 2) / (2 * D) y = ((r1 ** 2 - r3 ** 2 + I ** 2 + J ** 2) / (2 * J)) - ((I * x) / J) z = math.sqrt(abs(r1 ** 2 - x ** 2 - y ** 2)) return x, y, z def cartesian_to_radii(x, y, z): """Use trilateration to convert cartesian coordinates to radii.""" r1 = math.sqrt(x ** 2 + y ** 2 + z ** 2) r2 = math.sqrt((x - D) ** 2 + y ** 2 + z ** 2) r3 = math.sqrt((x - I) ** 2 + (y - J) ** 2 + z ** 2) return r1, r2, r3
So, to convert the point (0, 0, 5) from the Cartesian coordinate system to the radii (in centimeters), I just need to call
cartesian_to_radii(0, 0, 5), which will return the lengths of each string (for the curious, they are
(5.0, 32.3, 32.2). This makes sense, as the scratcher will end up 5 cm directly below servo A, at equal distances from the other two servos). The robot is starting to shape up very nicely already.
Overcoming a few issues
One problem was converting the string length to degrees for the servos to move. Servos are addressed in degrees, so you can tell them to move by
180 or
-360, but what we need to know is how many centimeters to roll or unroll the string for. To find this, I measured the diameter
d of the winch and calculated it with the usual formula
πd. It came out to 60 degrees per cm, which was convenient, and I confirmed this by spooling a piece of string 10 times around the winch and measuring its length. This confirmed the theoretical result beautifully, so I could continue.
Another problem was calibrating and initializing the robot, as the three strings would already be extended to some length when the robot started up (i.e. each string would not be spooled all the way up, since they all have to meet at the scratcher initially). The robot knows nothing about the initial positions, so if it is ordered to go to the point
(16, 9.1, 19.7) (which corresponds to radii
(27, 27, 27)) it will try to unspool each string by 27 cm, even though the scratcher is already at that point to begin with. This was easy to overcome by just declaring the length of each string manually on initialization and then subtracting it from each new position, so that
(27, 27, 27) became
(0, 0, 0) and everything worked properly.
A third problem (I know, they never stop) was that each motion to a new point was given in absolute radii (e.g.
(30, 22, 14)), which meant that the scratcher will only need to move for the difference of the two distances, rather than the absolute length of the string again. In the previous example, to move to the given point from
(25, 22, 20), the scratcher actually needed to move by
(5, 0, -6) cm on each servo. This was initially accomplished by keeping the current position of the scratcher in memory and subtracting that from the new one to find the delta, but I subsequently found out that each servo knows how far it has moved since the program started, and I just subtracted the motor-reported position instead, which improved accuracy.
The final code for that part looked like this:
# These are absolute radii, thanks to motcont. radii = (r1, r2, r3) #]
The robot was ready for a first run! Here it is, performing ten motions and stopping:
Avoiding oscillations
The motor moving functions built into the NXT brick (the Mindstorms computer that controls all the servos and sensors) are prone to oscillation, so the movements would be a bit jerky at the end, and nxt-python depended on reading the motors’ states to know when to stop them, which would mean that it wasn’t as accurate as software running on the brick itself. However, I discovered that nxt-python supported Motor Control, which is a very useful NXC program that runs directly on the brick to control the motor with great accuracy and produce very smooth movement.
Running on the brick
At this point, the robot was working very well, but there was still some work to be done. The code needed to be able to run on the brick, both for portability and because I wanted to see how easy NXC was to program for. However, I knew very little C and absolutely no NXC at the time, so the task seemed daunting. I regularly find myself thinking back to that lazy summer afternoon now, which seems like mere hours ago (because it was), and laugh at my youthful inexperience.
Learning NXC wasn’t as hard as I expected, I had to get used to the type system and the fact that indentation doesn’t define blocks (curse you, C!), but I quite like static typing and structs now. Translating the program took at most half an hour, and integrating it with motcont and debugging a few issues (hint: use
MotorBlockTachoCount() to get the motor’s tachometer reading, don’t waste two frustrating hours with
MotorTachoCount() like I did) took another three.
For a small comparison between the two approaches, here is the same code listing in Python and NXC:
def move_to_radii(self, r1, r2, r3): "Move to the given radii, relative to the starting position." # These are absolute radii, thanks to motcont. radii = (r1, r2, r3) # Sanity checks. radii = [max(radius, 5) for radius in radii] #] ports = (PORT_A, PORT_B, PORT_C) for port, degrees in zip(ports, degrees): self.motcont.move_to(port, self.power, int(degrees), smoothstart=1, brake=1) while not all(self.motcont.is_ready(port) for port in ports): time.sleep(0.1) def move_to(self, x, y, z): print "Moving to", x, y, z r1, r2, r3 = cartesian_to_radii(x, y, z) print "Moving to radii", r1, r2, r3 self.move_to_radii(r1, r2, r3)
void wait_for_motors() { // Wait for all the motors to stop moving. while(taskArunning) { Wait(50); } while(taskBrunning) { Wait(50); } while(taskCrunning) { Wait(50); } } void move_to_radius(const byte &port, float radius) { // Move to the given (absolute) radius. long degrees = radius * CM; int powersign = 1; // Subtract the motor's current position from the desired one to get // the absolute position. degrees = degrees - MotorBlockTachoCount(port); if (degrees < 0) { degrees = abs(degrees); powersign = -1; } // Move to that position. switch(port) { case OUT_A: motorParamsA.power = powersign * POWER; motorParamsA.tacholimit = degrees; taskArunning = true; start MoveA; break; case OUT_B: motorParamsB.power = powersign * POWER; motorParamsB.tacholimit = degrees; taskBrunning = true; start MoveB; break; case OUT_C: motorParamsC.power = powersign * POWER; motorParamsC.tacholimit = degrees; taskCrunning = true; start MoveC; break; } } void move_to_radii(radii input) { // Move to the given radii, relative to the starting position. // Subtract the new position from the initial position. Since the software // doesn't know we're at some point (x, y, z) to begin with, it treats the // starting position as (0, 0, 0). The calculation here compensates for that. input.r1 = input.r1 - INITIAL_RADII.r1; input.r2 = input.r2 - INITIAL_RADII.r2; input.r3 = input.r3 - INITIAL_RADII.r3; ResetScreen(); TextOut(0, LCD_LINE1, "Moving to:"); NumOut(0, LCD_LINE2, input.r1); NumOut(0, LCD_LINE3, input.r2); NumOut(0, LCD_LINE4, input.r3); // Move. move_to_radius(OUT_A, input.r1); move_to_radius(OUT_B, input.r2); move_to_radius(OUT_C, input.r3); // Wait for all the motors to stop moving. wait_for_motors(); } void move_to(point input) { // Sanity check. if (input.z < 5) input.z = 5; // Move to the specified Cartesian point. radii target = cartesian_to_radii(input); move_to_radii(target); }
You can see that the NXC code is more verbose, with about half the blame resting on NXC’s verbosity compared to Python, and the other half on the fact that
nxt-python abstracted some things very nicely from us. However, both listings are reasonably easy to read and understand, and both were rather easy to write, even for someone with no previous familiarity with NXC.
The NXC documentation (at 1500 pages) is very sparse, though complete. The library functions are not very well documented (see the
MotorBlockTachoCount vs
MotorTachoCount debacle above), which was a bit frustrating when trying to find out why things didn’t work, and the community is very small as well, so searching the internet didn’t yield too much in that respect. Hopefully this post will be helpful to those who come after me, that they may stand on the shoulders of giants.
A short while after, the complete NXC program was uploaded to the brick and was running beautifully. I added some touches like graceful reset when pressing the center button, raising and lowering the plane of motion with the left/right buttons, etc. Here is the finished thing in all its geeky glory:
And that’s pretty much it for this project! The next step is to make it larger and better and scratchier. I still haven’t tested it on me, but I hope it works, otherwise this whole project will have been an abject failure and an exercise in futility.
You can find the sources for both the Python and NXC versions (you know, to build your own or whatnot) at the back-scratcher GitHub repository. If you have any comments, feedback or insight on things I did wrong, leave a comment below! | https://www.stavros.io/posts/developing-back-scratching-robot/ | CC-MAIN-2017-39 | refinedweb | 2,662 | 66.37 |
Hallo everyone.
Newbie here, trying to learn.
I have some data points on the (x,y) field that are supposed to be cotegorised into two categories denoted here with X and O like this
import numpy as np import matplotlib.pyplot as plt x1 = np.array([0.1,0.3,0.1,0.6,0.4,0.6,0.5,0.9,0.4,0.7]) x2 = np.array([0.1,0.4,0.5,0.9,0.2,0.3,0.6,0.2,0.4,0.6]) c=np.array([ 1,1,1,1,1,0,0,0,0,0 ]) plt.plot(x1[c==0], x2[c==0], 'bo') plt.plot(x1[c==1], x2[c==1], 'rx')
Now I want to find a way so I can find the “best fitting curve” separating those like this
First I though maybe I try nearest neighbor method but I’ve been told it cannot apply here and that there’s a much simpler way to do it with an ANN but I can’t understand how.
Any ideas on what to use and/or how to do it?
Thank you everyone in advance! | https://discuss.pytorch.org/t/separate-data-points-into-two-categories/102601 | CC-MAIN-2022-21 | refinedweb | 194 | 82.95 |
- 06 Apr, 2021 16 commits
As noted by #19589, `stack` is not stateful and therefore must be passed `--nix` on every invocation. Do so. Fixes #19589.
Not only does this eliminate some code duplication but we also add a maximum core count to HLint's command-line, hopefully avoiding issue #19600.
- Simon Jakobi authored
See #17018.
- Łukasz Gołębiewski authored
It is incorrectly displayed in hackage as: `m1 <*> m2 = m1 >>= (x1 -> m2 >>= (x2 -> return (x1 x2)))` which isn't correct Haskell
In version 0.12.2.0 of vector when used with GHC-9.0 we rebox values from storeable mutable vectors. This should catch such a change in the future.
- Luite Stegeman authored
and not just the name on the binary on the `$PATH`.
Fixes #19616. This commit changes the `GHC.Driver.Errors.handleFlagWarnings` function to rely on the newly introduced `DiagnosticReason`. This allows us to correctly pretty-print the flags which triggered some warnings and in turn remove the cruft around this function (like the extra filtering and the `shouldPrintWarning` function.
This commit introduces a new `Severity` type constructor called `SevIgnore`, which can be used to classify diagnostic messages which are not meant to be displayed to the user, for example suppressed warnings. This extra constructor allows us to get rid of a bunch of redundant checks when emitting diagnostics, typically in the form of the pattern: ``` when (optM Opt_XXX) $ addDiagnosticTc (WarningWithFlag Opt_XXX) ... ``` Fair warning! Not all checks should be omitted/skipped, as evaluating some data structures used to produce a diagnostic might still be expensive (e.g. zonking, etc). Therefore, a case-by-case analysis must be conducted when deciding if a check can be removed or not. Last but not least, we remove the unnecessary `CmdLine.WarnReason` type, which is now redundant with `DiagnosticReason`.
-
In the common case where the list of ticks is empty, building a thunk just applies 'reverse' to '[]' which is quite wasteful.
- Oleg Grenrus authored
This allows Other Numbers to be used in identifiers, and also documents other, already existing lexer divergence from Haskell Report
To support proper parsing of arm64 targets, we needed to adjust the GHC_LLVM_TARGET function to allow parsing arm64-apple-darwin into aarch64. This however discared the proper os detection. To rectify this, we'll pull the os detection into separate block. Fixes #19173.
- 02 Apr, 2021 8 commits
- Sebastian Graf authored
It appears that the issue has already been fixed. Judging by the use of a pattern synonym with a provided constraint, my bet is on 1793ca9d. Fixes #19622.
Ticket #19576 noted that a test that failed in correctness (e.g. due to stderr mismatch) *and* failed due to a metrics change would report misleading stats. This was due to the testsuite driver *first* checking stats, before checking for correctness. Fix this. Closes #19576.
We don't want these failing merely due to performance metrics
Ensure that deb10-dwarf artifacts are preserved.
These now live in the ghc-tarballs/mingw-w64 directory. Fixes #19316.
- 01 Apr, 2021 16 commits
-
-
This commit further expand on the design for #18516 by getting rid of the `defaultReasonSeverity` in favour of a function called `diagReasonSeverity` which correctly takes the `DynFlags` as input. The idea is to compute the `Severity` and the `DiagnosticReason` of each message "at birth", without doing any later re-classifications, which are potentially error prone, as the `DynFlags` might evolve during the course of the program. In preparation for a proper refactoring, now `pprWarning` from the Parser.Ppr module has been renamed to `mkParserWarn`, which now takes a `DynFlags` as input. We also get rid of the reclassification we were performing inside `printOrThrowWarnings`. Last but not least, this commit removes the need for reclassify inside GHC.Tc.Errors, and also simplifies the implementation of `maybeReportError`. Update Haddock submodule
- Vladislav Zavialov authored
When the CharToNat and NatToChar type families were added, the corresponding axioms were not exported. This led to a failure much like #14934
As noted in my comment on #19058, this comment was previously a bit misleading in the case of stable branches.
Also make the HomeUnit optional to keep the field strict and prepare for UnitEnvs without a HomeUnit (e.g. in Plugins envs, cf #14335).
- Oleg Grenrus authored
- Remove GHC.OldList - Remove Data.OldList - compat-unqualified-imports is no-op - update haddock submodule | https://gitlab.haskell.org/ghc/ghc/-/commits/eac9d3764a35b6c219d74d750bad9d8e790cff77 | CC-MAIN-2021-21 | refinedweb | 717 | 55.03 |
XSetEventQueueOwner (3) - Linux Man Pages
XSetEventQueueOwner: set event queue owner on a shared Xlib/XCB connection
NAMEXSetEventQueueOwner - set event queue owner on a shared Xlib/XCB connection
SYNTAX
#include <X11/Xlib-xcb.h>
- void XSetEventQueueOwner(Display *dpy, enum XEventQueueOwner owner);
ARGUMENTS
- dpy
- Specifies the connection to the X server.
- owner
- Specifies the event queue ownership:
- XlibOwnsEventQueue (default)
- Xlib owns the event queue. Use the Xlib event-handling functions. Do not call the XCB event-handling functions.
- XCBOwnsEventQueue
- XCB owns the event queue. Use the XCB event-handling functions. Do not call the Xlib event-handling functions.
DESCRIPTIONWhile a client using Xlib/XCB can issue requests and handle their replies or errors with either Xlib or XCB, only one can own and handle the event queue. By default, Xlib must own the event queue, for compatibility with legacy Xlib clients. Clients can call XSetEventQueueOwner immediately after XOpenDisplay to let XCB own the event queue instead. Clients may not call XSetEventQueueOwner at any other time, as this will potentially lose responses.
SEE ALSOXOpenDisplay(3), XGetXCBConnection(3),
Xlib - C Language X Interface | https://www.systutorials.com/docs/linux/man/3-XSetEventQueueOwner/ | CC-MAIN-2021-25 | refinedweb | 179 | 58.48 |
The QStaticText class enables optimized drawing of text when the text and its layout is updated rarely. More...
#include <QStaticText>
This class was introduced in Qt 4.7.
The QStaticText class enables optimized drawing of text when the text and its layout is updated rarely. = 0) :.
QStaticText will attempt to guess the format of the input text using Qt::mightBeRichText(). To force QStaticText to display its contents as either plain text or rich text, use the function QStaticText::setTextFormat() and pass in, respectively, Qt::PlainText and Qt::RichText.GLWidget.Matrix().().
Sets the text of the QStaticText to text.
Note: This function will cause the layout of the text to require recalculation.().
Sets the text option structure that controls the layout process to the given textOption.
See also textOption().().
Returns the size of the bounding rect for this QStaticText..
Assigns other to this QStaticText.
Compares other to this QStaticText. Returns true if the texts, fonts and text widths are equal. | http://idlebox.net/2010/apidocs/qt-everywhere-opensource-4.7.0.zip/qstatictext.html | CC-MAIN-2014-15 | refinedweb | 159 | 68.06 |
In the last article, we updated the enemy from a capsule to sprite art. In this article, we'll add art for our shield powerup.
Add SpriteRenderer
I'll add a child GameObject to the Player called Shield and add a SpriteRenderer component with the new shield sprite.
Since we need to activate and deactivate the shield GameObject, I'll reference it in the Player script where we are handling powerup activation. Then, I'll assign the shield GameObject in the inspector.
public class Player : MonoBehaviour { ... [ ] private GameObject shieldPrefab; ... }
In a previous post, we added the
shieldsRemaining variable which we can reuse here to know whether or not the shield should be active. I'll create a new method called
HandleShieldDisplay that we'll call from the
Update method.
private void HandleShieldDisplay() { if (shieldsRemaining > 0 && !shieldPrefab.activeSelf) { shieldPrefab.SetActive(true); } }
private void Update() { RespondToMovement(); RespondToAttack(); HandleShieldDisplay(); }
In the
ProtectedByShield method, we'll call
SetActive(false) if we no longer have shields remaining.
private bool ProtectedByShield() { if (shieldsRemaining > 0) { shieldsRemaining--; return true; } else { shieldPrefab.SetActive(false); } return false; }
Here's the result.
Summary
We're done! We'll add more polish to the shield later, but for now, it's functional and we can finally visualize the shield when the powerup is activated.
Take care.
Stay awesome. | https://blog.justinhhorner.com/adding-shield-art | CC-MAIN-2022-27 | refinedweb | 216 | 57.98 |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.