qid int64 1 74.7M | question stringlengths 12 33.8k | date stringlengths 10 10 | metadata list | response_j stringlengths 0 115k | response_k stringlengths 2 98.3k |
|---|---|---|---|---|---|
171,727 | How do i delete all the tables in the schema on Apache Derby DB using JDBC? | 2008/10/05 | [
"https://Stackoverflow.com/questions/171727",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/15100/"
] | For actual code that does this, check [CleanDatabaseTestSetup.java](http://svn.apache.org/viewvc/db/derby/code/trunk/java/org.apache.derby.tests/org/apache/derbyTesting/junit/CleanDatabaseTestSetup.java?view=markup) in the Derby test suite section of the Derby distribution. | I think most db providers don't allow DROP TABLE \* (or similar).
I think the best way would be to SHOW TABLES and then go through each deleting in a loop via a resultset.
HTH. |
29,926 | **Location**: Northern China
**Height**: I guess it's over 15m, about 20m.
**Note**: All leaves would fall out in the winter.
[](https://i.stack.imgur.com/NaNLy.jpg)
[](https://i.stack.imgur.com/c5TA5.jpg) | 2016/11/20 | [
"https://gardening.stackexchange.com/questions/29926",
"https://gardening.stackexchange.com",
"https://gardening.stackexchange.com/users/16267/"
] | Thanks! @Bamboo, @stormy, @Stephie
I have known it.
It's **Populus alba**.
See here → [Wiki](https://en.wikipedia.org/wiki/Populus_alba) | I think this is Alnus rubra or Red Alder. A very tough tree. |
64,559 | I'm currently 16 and have been invited to attend a National Youth Conference for National Security in Washington DC this upcoming fall. I just moved in with my mom and this trip isn't exactly ideal for us financially. My mom said I was more than welcome to go on the trip as long as I came up with the money. I could make the money over the summer but the enrollment deadline is June 24. I've made a Go Fund Me page but I don't think that will help in time. I'm not sure how old I must be to take out a loan or anything about the process. Any help/advice is appreciated in this situation | 2016/05/28 | [
"https://money.stackexchange.com/questions/64559",
"https://money.stackexchange.com",
"https://money.stackexchange.com/users/42685/"
] | At your age, the only place you are going to get a loan is from relatives. If you can't... Go to next year's conference. Missing it this year might feel like a disaster, but it really, really isn't. | In general, you would have to be the age of majority (generally, 18) to take out a loan. Additionally, your credit rating must be sufficient for the bank or loan company to be comfortable loaning you money. |
64,559 | I'm currently 16 and have been invited to attend a National Youth Conference for National Security in Washington DC this upcoming fall. I just moved in with my mom and this trip isn't exactly ideal for us financially. My mom said I was more than welcome to go on the trip as long as I came up with the money. I could make the money over the summer but the enrollment deadline is June 24. I've made a Go Fund Me page but I don't think that will help in time. I'm not sure how old I must be to take out a loan or anything about the process. Any help/advice is appreciated in this situation | 2016/05/28 | [
"https://money.stackexchange.com/questions/64559",
"https://money.stackexchange.com",
"https://money.stackexchange.com/users/42685/"
] | To explain *why* you have to be 18: If you are not 18, then any contract that you sign can be voided (made invalid) by either you or your parents. So it would be completely legal for you to go to the bank, ask for a $1000 loan, and for the bank to give you the loan. But then you could spend the money, and tell the bank "sorry, I changed my mind, I don't want that loan, and sorry again, but the money is gone". At that point, there would be nothing the bank could do to get their money back.
Obviously, banks don't like this, so they won't lend you money. | In general, you would have to be the age of majority (generally, 18) to take out a loan. Additionally, your credit rating must be sufficient for the bank or loan company to be comfortable loaning you money. |
44,041 | I have two workstations A and B connected to the same L3 switch at 1Gbps. Workstation A generates an MPEG2-TS UDP video stream at **10Mbps** data rate. Workstation B receives this stream correctly. The switch is connected to an edge router via 100Mbps port.
Workstation C, which is on the other end of a private WAN, receives poor quality video stream: the first N lines of the image are good quality (N randomly changes) and the other lines suffers severe pixel blocks. WAN link capacity is 20Mbps.
The fact the first N lines are always good quality made me think it is not random packet loss. However I didn't understand at all why a 10Mbps stream could saturate a 20Mbps link.
To my surprise, after limiting NIC on workstation A to 100Mbps, workstation C could correctly receive and display the video stream. Why? | 2017/09/11 | [
"https://networkengineering.stackexchange.com/questions/44041",
"https://networkengineering.stackexchange.com",
"https://networkengineering.stackexchange.com/users/27712/"
] | The likely cause of this is small buffers in the switch combined with poor design of the video streaming application.
Most likely the video streaming application doesn't send a paced stream of packets but instead passes a whole frame worth of packets to the OS at once. The buffers in the client OS and the edge router are big enough to handle this but the buffers in the switch are not.
Workstation A sends that burst of packets to the switch at 1Gbps but the switch can only send it to the edge router at 100MBps. The buffer in the switch is too small to handle the burst and so packets get dropped.
Dropping the link to 100Mbps on workstation A means that packets no longer pile up at the switch because the input and output ports are running at the same speed.
You should be able to confirm this by looking at frame loss counters on the switch. | There are several possibilities:
1. Workstation C's cable causes errors = frame drops at gigabit speed or with all twisted pairs in use. Check the workstation's error counter at full speed under load. You can check either side for 1000BASE-T as pairs are used bidirectionally.
2. There is a congestion or buffering problem on the way to workstation C. Check routers and switches in between for errors/congestion.
3. There is a setup problem (jumbo frames, MTU mismatch or misdetection). |
13,997,755 | I'm wondering if it's possible to search for a certain line of a text using Xcode's Find & Replace feature, and fully delete the line so not even blank space is left over. Is this possible and if so how? | 2012/12/21 | [
"https://Stackoverflow.com/questions/13997755",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/875640/"
] | Copy the line you want to delete, including the newline character at the end of the line by triple-clicking on it (the selection should go all the way to the far right side of the editor pane). Perform a find and replace; paste the line into the the top field, and leave the replace field blank. Click Replace All. | On the latest Xcode you can just insert line break in the search field. Click on magnifying glass icon -> insert pattern -> Line Break
[](https://i.stack.imgur.com/OZvq2.gif) |
606,419 | Earlier today I asked wether it would be a good idea to develop websites using C#. Most of the answers pointed towards .NET and ASP. Currently I develop with PHP. I've dabbled with Python and RoR but I always come back to PHP. This is the first time I've looked at .NET and ASP. A bucket load of Google searches later I'm not really seeing much support for ASP online but then it all seems a bit Biased towards PHP/Apache/MySQL.
It looks like there's a fair amount of .NET and ASP folk around here so I figured it's worth a shot asking for their input in attempt to try and address the balance in my own head. It can't all be bad.
What advantages are there to .NET and ASP over PHP? | 2009/03/03 | [
"https://Stackoverflow.com/questions/606419",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/64586/"
] | Have a look at Phalanger. It is PHP running on the .Net Framework and has been making some huge strides in the last few months. Definitly worth investigating when coming from PHP.
[Phalanger](http://www.codeplex.com/Wiki/View.aspx?ProjectName=Phalanger) | I stopped using PHP before PHP5 was out so I my views on PHP are very outdated I suppose. Nevertheless, what I liked about C# (ASP.NET) was that it forced me into acquiring better programming practices (OO in particular). PHP4 was not object oriented. Maybe the later versions of PHP are different. The greatest obstacle I encountered when shifting from PHP to ASP.NET was understanding OO. If objects are not second nature to your programming style, you're likely to find out that your ASP.NET learning curve is going to be much shallower than it was with PHP. |
606,419 | Earlier today I asked wether it would be a good idea to develop websites using C#. Most of the answers pointed towards .NET and ASP. Currently I develop with PHP. I've dabbled with Python and RoR but I always come back to PHP. This is the first time I've looked at .NET and ASP. A bucket load of Google searches later I'm not really seeing much support for ASP online but then it all seems a bit Biased towards PHP/Apache/MySQL.
It looks like there's a fair amount of .NET and ASP folk around here so I figured it's worth a shot asking for their input in attempt to try and address the balance in my own head. It can't all be bad.
What advantages are there to .NET and ASP over PHP? | 2009/03/03 | [
"https://Stackoverflow.com/questions/606419",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/64586/"
] | Used:
>
> asp.net vs php site:stackoverflow.com
>
>
>
in Google search and got:
[ASP.NET vs. PHP](https://stackoverflow.com/questions/304948/aspnet-vs-php)
[The use of PHP vs ASP.net](https://stackoverflow.com/questions/543458/the-use-of-php-vs-asp-net-closed)
[PHP MVC (symfony/Zend) vs ASP MVC vs Spring MVC vs Ruby on Rails?](https://stackoverflow.com/questions/253785/php-mvc-symfony-zend-vs-asp-mvc-vs-spring-mvc-vs-ruby-on-rails)
[Career with PHP or with ASP.NET?](https://stackoverflow.com/questions/558124/career-with-php-or-with-asp-net) | I stopped using PHP before PHP5 was out so I my views on PHP are very outdated I suppose. Nevertheless, what I liked about C# (ASP.NET) was that it forced me into acquiring better programming practices (OO in particular). PHP4 was not object oriented. Maybe the later versions of PHP are different. The greatest obstacle I encountered when shifting from PHP to ASP.NET was understanding OO. If objects are not second nature to your programming style, you're likely to find out that your ASP.NET learning curve is going to be much shallower than it was with PHP. |
606,419 | Earlier today I asked wether it would be a good idea to develop websites using C#. Most of the answers pointed towards .NET and ASP. Currently I develop with PHP. I've dabbled with Python and RoR but I always come back to PHP. This is the first time I've looked at .NET and ASP. A bucket load of Google searches later I'm not really seeing much support for ASP online but then it all seems a bit Biased towards PHP/Apache/MySQL.
It looks like there's a fair amount of .NET and ASP folk around here so I figured it's worth a shot asking for their input in attempt to try and address the balance in my own head. It can't all be bad.
What advantages are there to .NET and ASP over PHP? | 2009/03/03 | [
"https://Stackoverflow.com/questions/606419",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/64586/"
] | Used:
>
> asp.net vs php site:stackoverflow.com
>
>
>
in Google search and got:
[ASP.NET vs. PHP](https://stackoverflow.com/questions/304948/aspnet-vs-php)
[The use of PHP vs ASP.net](https://stackoverflow.com/questions/543458/the-use-of-php-vs-asp-net-closed)
[PHP MVC (symfony/Zend) vs ASP MVC vs Spring MVC vs Ruby on Rails?](https://stackoverflow.com/questions/253785/php-mvc-symfony-zend-vs-asp-mvc-vs-spring-mvc-vs-ruby-on-rails)
[Career with PHP or with ASP.NET?](https://stackoverflow.com/questions/558124/career-with-php-or-with-asp-net) | I'd say it depends on your background and how much money you have to throw around too. ASP.net has some great features but you may not even need them depending on your project. The tools are expensive, the hosting is expensive.
PHP is great because you get a lot for free, but there are trade offs.
Personally I like .NET better because thats what I started off with, I feel like I can do more with less, but thats a personal preference. I'm sure some vet php developers feel the exact same way too. |
606,419 | Earlier today I asked wether it would be a good idea to develop websites using C#. Most of the answers pointed towards .NET and ASP. Currently I develop with PHP. I've dabbled with Python and RoR but I always come back to PHP. This is the first time I've looked at .NET and ASP. A bucket load of Google searches later I'm not really seeing much support for ASP online but then it all seems a bit Biased towards PHP/Apache/MySQL.
It looks like there's a fair amount of .NET and ASP folk around here so I figured it's worth a shot asking for their input in attempt to try and address the balance in my own head. It can't all be bad.
What advantages are there to .NET and ASP over PHP? | 2009/03/03 | [
"https://Stackoverflow.com/questions/606419",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/64586/"
] | Used:
>
> asp.net vs php site:stackoverflow.com
>
>
>
in Google search and got:
[ASP.NET vs. PHP](https://stackoverflow.com/questions/304948/aspnet-vs-php)
[The use of PHP vs ASP.net](https://stackoverflow.com/questions/543458/the-use-of-php-vs-asp-net-closed)
[PHP MVC (symfony/Zend) vs ASP MVC vs Spring MVC vs Ruby on Rails?](https://stackoverflow.com/questions/253785/php-mvc-symfony-zend-vs-asp-mvc-vs-spring-mvc-vs-ruby-on-rails)
[Career with PHP or with ASP.NET?](https://stackoverflow.com/questions/558124/career-with-php-or-with-asp-net) | I've come from a background in Perl/CGI, Classic ASP, and ASP.NET. I decided to take up PHP to see why there is such a tremendous following. I feel like I've taken a step backwards in the language scale and would rather code in .NET or Perl.
I think Jeff Atwood would up-mod me on this. |
606,419 | Earlier today I asked wether it would be a good idea to develop websites using C#. Most of the answers pointed towards .NET and ASP. Currently I develop with PHP. I've dabbled with Python and RoR but I always come back to PHP. This is the first time I've looked at .NET and ASP. A bucket load of Google searches later I'm not really seeing much support for ASP online but then it all seems a bit Biased towards PHP/Apache/MySQL.
It looks like there's a fair amount of .NET and ASP folk around here so I figured it's worth a shot asking for their input in attempt to try and address the balance in my own head. It can't all be bad.
What advantages are there to .NET and ASP over PHP? | 2009/03/03 | [
"https://Stackoverflow.com/questions/606419",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/64586/"
] | Used:
>
> asp.net vs php site:stackoverflow.com
>
>
>
in Google search and got:
[ASP.NET vs. PHP](https://stackoverflow.com/questions/304948/aspnet-vs-php)
[The use of PHP vs ASP.net](https://stackoverflow.com/questions/543458/the-use-of-php-vs-asp-net-closed)
[PHP MVC (symfony/Zend) vs ASP MVC vs Spring MVC vs Ruby on Rails?](https://stackoverflow.com/questions/253785/php-mvc-symfony-zend-vs-asp-mvc-vs-spring-mvc-vs-ruby-on-rails)
[Career with PHP or with ASP.NET?](https://stackoverflow.com/questions/558124/career-with-php-or-with-asp-net) | Here's a reason why you should keep using PHP:
<http://www.slideshare.net/eplawless/exception-safety-and-garbage-collection-and-some-other-stuff> |
606,419 | Earlier today I asked wether it would be a good idea to develop websites using C#. Most of the answers pointed towards .NET and ASP. Currently I develop with PHP. I've dabbled with Python and RoR but I always come back to PHP. This is the first time I've looked at .NET and ASP. A bucket load of Google searches later I'm not really seeing much support for ASP online but then it all seems a bit Biased towards PHP/Apache/MySQL.
It looks like there's a fair amount of .NET and ASP folk around here so I figured it's worth a shot asking for their input in attempt to try and address the balance in my own head. It can't all be bad.
What advantages are there to .NET and ASP over PHP? | 2009/03/03 | [
"https://Stackoverflow.com/questions/606419",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/64586/"
] | I'd say it depends on your background and how much money you have to throw around too. ASP.net has some great features but you may not even need them depending on your project. The tools are expensive, the hosting is expensive.
PHP is great because you get a lot for free, but there are trade offs.
Personally I like .NET better because thats what I started off with, I feel like I can do more with less, but thats a personal preference. I'm sure some vet php developers feel the exact same way too. | Have a look at Phalanger. It is PHP running on the .Net Framework and has been making some huge strides in the last few months. Definitly worth investigating when coming from PHP.
[Phalanger](http://www.codeplex.com/Wiki/View.aspx?ProjectName=Phalanger) |
606,419 | Earlier today I asked wether it would be a good idea to develop websites using C#. Most of the answers pointed towards .NET and ASP. Currently I develop with PHP. I've dabbled with Python and RoR but I always come back to PHP. This is the first time I've looked at .NET and ASP. A bucket load of Google searches later I'm not really seeing much support for ASP online but then it all seems a bit Biased towards PHP/Apache/MySQL.
It looks like there's a fair amount of .NET and ASP folk around here so I figured it's worth a shot asking for their input in attempt to try and address the balance in my own head. It can't all be bad.
What advantages are there to .NET and ASP over PHP? | 2009/03/03 | [
"https://Stackoverflow.com/questions/606419",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/64586/"
] | I'd say it depends on your background and how much money you have to throw around too. ASP.net has some great features but you may not even need them depending on your project. The tools are expensive, the hosting is expensive.
PHP is great because you get a lot for free, but there are trade offs.
Personally I like .NET better because thats what I started off with, I feel like I can do more with less, but thats a personal preference. I'm sure some vet php developers feel the exact same way too. | I stopped using PHP before PHP5 was out so I my views on PHP are very outdated I suppose. Nevertheless, what I liked about C# (ASP.NET) was that it forced me into acquiring better programming practices (OO in particular). PHP4 was not object oriented. Maybe the later versions of PHP are different. The greatest obstacle I encountered when shifting from PHP to ASP.NET was understanding OO. If objects are not second nature to your programming style, you're likely to find out that your ASP.NET learning curve is going to be much shallower than it was with PHP. |
606,419 | Earlier today I asked wether it would be a good idea to develop websites using C#. Most of the answers pointed towards .NET and ASP. Currently I develop with PHP. I've dabbled with Python and RoR but I always come back to PHP. This is the first time I've looked at .NET and ASP. A bucket load of Google searches later I'm not really seeing much support for ASP online but then it all seems a bit Biased towards PHP/Apache/MySQL.
It looks like there's a fair amount of .NET and ASP folk around here so I figured it's worth a shot asking for their input in attempt to try and address the balance in my own head. It can't all be bad.
What advantages are there to .NET and ASP over PHP? | 2009/03/03 | [
"https://Stackoverflow.com/questions/606419",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/64586/"
] | I've come from a background in Perl/CGI, Classic ASP, and ASP.NET. I decided to take up PHP to see why there is such a tremendous following. I feel like I've taken a step backwards in the language scale and would rather code in .NET or Perl.
I think Jeff Atwood would up-mod me on this. | I stopped using PHP before PHP5 was out so I my views on PHP are very outdated I suppose. Nevertheless, what I liked about C# (ASP.NET) was that it forced me into acquiring better programming practices (OO in particular). PHP4 was not object oriented. Maybe the later versions of PHP are different. The greatest obstacle I encountered when shifting from PHP to ASP.NET was understanding OO. If objects are not second nature to your programming style, you're likely to find out that your ASP.NET learning curve is going to be much shallower than it was with PHP. |
606,419 | Earlier today I asked wether it would be a good idea to develop websites using C#. Most of the answers pointed towards .NET and ASP. Currently I develop with PHP. I've dabbled with Python and RoR but I always come back to PHP. This is the first time I've looked at .NET and ASP. A bucket load of Google searches later I'm not really seeing much support for ASP online but then it all seems a bit Biased towards PHP/Apache/MySQL.
It looks like there's a fair amount of .NET and ASP folk around here so I figured it's worth a shot asking for their input in attempt to try and address the balance in my own head. It can't all be bad.
What advantages are there to .NET and ASP over PHP? | 2009/03/03 | [
"https://Stackoverflow.com/questions/606419",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/64586/"
] | I'd say it depends on your background and how much money you have to throw around too. ASP.net has some great features but you may not even need them depending on your project. The tools are expensive, the hosting is expensive.
PHP is great because you get a lot for free, but there are trade offs.
Personally I like .NET better because thats what I started off with, I feel like I can do more with less, but thats a personal preference. I'm sure some vet php developers feel the exact same way too. | I've come from a background in Perl/CGI, Classic ASP, and ASP.NET. I decided to take up PHP to see why there is such a tremendous following. I feel like I've taken a step backwards in the language scale and would rather code in .NET or Perl.
I think Jeff Atwood would up-mod me on this. |
606,419 | Earlier today I asked wether it would be a good idea to develop websites using C#. Most of the answers pointed towards .NET and ASP. Currently I develop with PHP. I've dabbled with Python and RoR but I always come back to PHP. This is the first time I've looked at .NET and ASP. A bucket load of Google searches later I'm not really seeing much support for ASP online but then it all seems a bit Biased towards PHP/Apache/MySQL.
It looks like there's a fair amount of .NET and ASP folk around here so I figured it's worth a shot asking for their input in attempt to try and address the balance in my own head. It can't all be bad.
What advantages are there to .NET and ASP over PHP? | 2009/03/03 | [
"https://Stackoverflow.com/questions/606419",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/64586/"
] | Used:
>
> asp.net vs php site:stackoverflow.com
>
>
>
in Google search and got:
[ASP.NET vs. PHP](https://stackoverflow.com/questions/304948/aspnet-vs-php)
[The use of PHP vs ASP.net](https://stackoverflow.com/questions/543458/the-use-of-php-vs-asp-net-closed)
[PHP MVC (symfony/Zend) vs ASP MVC vs Spring MVC vs Ruby on Rails?](https://stackoverflow.com/questions/253785/php-mvc-symfony-zend-vs-asp-mvc-vs-spring-mvc-vs-ruby-on-rails)
[Career with PHP or with ASP.NET?](https://stackoverflow.com/questions/558124/career-with-php-or-with-asp-net) | Have a look at Phalanger. It is PHP running on the .Net Framework and has been making some huge strides in the last few months. Definitly worth investigating when coming from PHP.
[Phalanger](http://www.codeplex.com/Wiki/View.aspx?ProjectName=Phalanger) |
25,996 | Say I have an X.509 cert and a private key that corresponds to it. I can import X.509 certs easily enough into Windows but what about private keys?
Is the only way I can do that by converting both the cert and the private key to a "Personal Information Exchange (PKCS #12)" file and importing that?
Maybe this question would be better on superuser.com? Either way, thanks! | 2012/12/26 | [
"https://security.stackexchange.com/questions/25996",
"https://security.stackexchange.com",
"https://security.stackexchange.com/users/15922/"
] | A PKCS12 (\*.p12, or \*.pfx) is absolutely the easy way. There are quite a few common tools out there for combining a key pair and certificate into a p12. My favorite is OpenSSL, since it works on every OS I've ever needed to use it on and it's reasonably standards compliant. [Here](https://www.google.com/#hl=en&tbo=d&sclient=psy-ab&q=creating+a+pkcs12+with+openssl&oq=creating+a+PKCS&gs_l=hp.3.2.0l3j0i30.1266.5892.0.8936.20.20.0.0.0.0.208.2028.13j6j1.20.0.les;eqn,rate_low=0-035,rate_high=0-035,min_length=2,cconf=1-2,second_pass=false,num_suggestions=1,ignore_bad_origquery=true,onetoken=false..0.0...1c.1.TwORQ-ztZbQ&pbx=1&bav=on.2,or.r_gc.r_pw.r_cp.r_qf.&bvm=bv.1355534169,d.dmQ&fp=a5dcfad2a6298f40&bpcl=40096503&biw=1229&bih=853)'s a diverse collection of pages on how, although mileage will vary based upon how your key pair and certificate are currently stored.
Also - most devices with an export capability will offer a PKCS12 generation option if the settings allow key export - its more or less the standard for most PKI enabled applications, and the few cases where this is not the norm (Java for example), there is still usually a conversion or export capability.
One note - if you have a case where your key is on a hardware token or module, you can still reference it from the Microsoft Cert Store - you just need to import the certificate and instruct Microsoft on where the key is stored... to do this, you need to follow the device's instructions for updating the certificate store. | Pub/priv key pairs should be imported into Windows using a PKCS12 (.p12/pfx) when you're using it as a client certificate. That's all there is to it here...
If you're importing it into IIS that's a bit different, but that doesn't seem to be what you're doing. Just in case - IIS requires a slightly different format than X.509 for its certificates; it requires a PKCS7 instead of generic X.509 because PKCS7 includes the signer certificates, whereas X.509 only has the individual certificate which has been signed. This differs from the typical Apache implemention where the signer certificates are included in a [trusted] cert bundle. |
109,351 | I have my D7000 set to use its second SD Card slot to back up and I am shooting in raw (NEF).
Every image is shown twice in playback mode, and when the images are imported to Photos (MacOS). This makes deleting individual images a pain.
As it is copying the images to both cards it makes some sense, but the menu says "backup" not "duplicate" so I would at least expect the internal firmware to understand and not show the images twice.
To clarify a little, when in playback/review mode, I see the images in chronological order, first for card 1 then again for card 2, so if I have taken images A, B and C I would see A1 -> B1 -> C1 -> A2 -> B2 -> B2 (1 and 2 represent the card slot).
So to delete image B I have to delete two images, once for each card.
Is this normal behaviour?
Firmware is
A 1.04
B 1.05
L 1.002 | 2019/07/06 | [
"https://photo.stackexchange.com/questions/109351",
"https://photo.stackexchange.com",
"https://photo.stackexchange.com/users/83136/"
] | After the clarifications, what you describe is normal behavior. I simply leave the backup card alone and format it entirely when I am certain I won't need the backup copies. If you are concerned that the card(s) will fill w/ unwanted pictures and stop being able to record then I would just get a larger backup card (2-4x the size of the primary card). | Have you [chosen a memory card slot for playback](http://download.nikonimglib.com/archive2/j0v3l00Dv39x01U97ft13W9kOV17/D7000_EU(En)06.pdf) (page 164)? Otherwise (page 163) "The most recent photograph will be displayed in the monitor", which I'm taking to mean in chronological order irrespective of card slot.
"Photo apps" is a very broad term, but if your software is importing everything from the camera it may also be adopting a chronological display order.
You might be able to get round this by manually selecting only one card slot for import, or by copying files from one card only to the directory used by the software. |
109,351 | I have my D7000 set to use its second SD Card slot to back up and I am shooting in raw (NEF).
Every image is shown twice in playback mode, and when the images are imported to Photos (MacOS). This makes deleting individual images a pain.
As it is copying the images to both cards it makes some sense, but the menu says "backup" not "duplicate" so I would at least expect the internal firmware to understand and not show the images twice.
To clarify a little, when in playback/review mode, I see the images in chronological order, first for card 1 then again for card 2, so if I have taken images A, B and C I would see A1 -> B1 -> C1 -> A2 -> B2 -> B2 (1 and 2 represent the card slot).
So to delete image B I have to delete two images, once for each card.
Is this normal behaviour?
Firmware is
A 1.04
B 1.05
L 1.002 | 2019/07/06 | [
"https://photo.stackexchange.com/questions/109351",
"https://photo.stackexchange.com",
"https://photo.stackexchange.com/users/83136/"
] | After the clarifications, what you describe is normal behavior. I simply leave the backup card alone and format it entirely when I am certain I won't need the backup copies. If you are concerned that the card(s) will fill w/ unwanted pictures and stop being able to record then I would just get a larger backup card (2-4x the size of the primary card). | That is perfectly normal behaviour based on the settings you described. If you want to reduce your time deleting duplicates on the computer, my suggestion would be to use a memory card reader and copy the images from a single card instead of copying the images through USB, using MTP(media transfer protocol). |
5,016,349 | Is there any way to restart Visual Studio 2010 (and possibly 2008 as well but not so important) manually and keeping the current state (i.e. all open solutions/projects and files)? Basically the same operation as when you install an extension and Visual Studio asks to restart itself. Occasionally Visual Studio gets confused after things like folder renames/moves, reference changes or the GUI editor throws a wobbly so it would be nice to be able to quickly restart the solution/project rather than close Visual Studio, reopen it and load the solution/project again. | 2011/02/16 | [
"https://Stackoverflow.com/questions/5016349",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/275751/"
] | I don't really like answering my own question but I found the [RestartStudio](http://visualstudiogallery.msdn.microsoft.com/f27f5495-3987-4e0f-8ce3-9a95efc05ce0) extension for Visual Studio 2010 that adds the restart option to the File menu and seems to work well. | [Visual Studio Restart](https://visualstudiogallery.msdn.microsoft.com/01f0a1ae-1513-48dd-9cf0-efb38419b480) is another plugin that works for Visual Studio 2013.
[Restart Visual Studio](https://marketplace.visualstudio.com/items?itemName=MarioHsiao.RestartVisualStudio) for 2015
[VSRestart2017](https://marketplace.visualstudio.com/items?itemName=vs-publisher-356819.VSRestart2017) for 2017
[Visual Studio Restart](https://marketplace.visualstudio.com/items?itemName=PaulMelia.VsRestart001) for 2017 & 2019
[Restart for Visual Studio 2022 Preview](https://marketplace.visualstudio.com/items?itemName=pedoc.RestartVisualStudioforvs2022preview) for 2022 |
50,524,391 | I am using jboss amq7.1/apache amq, When using replication as the HA policy for my cluster, it is documented that all data synchronization is done over the network, All persistent data received by the master broker is synchronized to the slave when the master drops from the network. A slave broker first needs to synchronize all existing data from the master broker before becoming capable of replacing it.
Per my understanding, if master broker is crashed instead of shutdown by administrator, no persistent data can be synced, therefore messages persisted in journal of master will be lost if the disk used by journal is broken, am I right? | 2018/05/25 | [
"https://Stackoverflow.com/questions/50524391",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/9207479/"
] | Your understanding is not correct.
All persistent data received by the master broker is replicated to the slave when the master broker receives it *so that* when the master broker drops from the network (e.g. due to a crash) the slave can replace the master.
Replicating the data from the master to the slave *when* the master drops from the network would completely defeat the purpose of high availability. | Actually, if HA is configured as Master/Slave, whether network or journal replicated, the receipt of a message to the broker is FIRST replicated and ONLY if successful, it will be confirmed as received to the client. |
18,485,750 | I am new to Erlang and besides reading books and manuals, I like to look at existing code. The site trapexit.org looked nice, but it is currently down.
Is there somebody out there that could restart the thing, or even better, is there a well maintained, up to date code repository somewhere else?
TIA | 2013/08/28 | [
"https://Stackoverflow.com/questions/18485750",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/1196579/"
] | [Erlang Central](https://erlangcentral.org/) has most of the content from Trapexit - check the Documentation tab. | Personally I'd look around at Bitbucket: <https://bitbucket.org/repo/all/relevance?name=erlang&language=erlang> or Github: <https://github.com/search?l=Erlang&q=erlang&ref=cmdform&type=Repositories>
But no, I do not know of any other Erlang-focused site similar to Trapexit |
27,627,964 | I have a symfony2 application also supporting REST. I would like to hear if it would be a good idea to go over the learning curve of angularjs or stick with jQuery and twig. It seems like twig already has some nice features similar to those in angularjs such as filters and stuff. Also if l use angular it will break symfon's MVC since I will most probably have less views . On the other hand I like the responsiveness of angular and it's like the new trend. Can you list some pros and cons in using angular in this scope?
**Update**
Thank you all for the detailed answers but I'm still missing the part where you say angularjs is not braking the server-side MVC. In a typical back-end MVC we have a bottom-up approach where the controller is communicating with the model to prepare the data to pass to the view. So my PostController will pass a list of Pot objects to the view and using twig I can nicely iterate over them and print their properties. On a typical angular application though, its the other way around. We have a top-down approach where the View starts with nothing and later communicates with the controller to get the data needed (typically in JSON format) to render different parts of the page. | 2014/12/23 | [
"https://Stackoverflow.com/questions/27627964",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/447738/"
] | * *Twig* is server-side, while *AngularJS* is client-side. You can't really compare it
* *AngularJS* is not breaking *Symfony*'s MVC. Symfony just serves another purpose: instead of providing a complete app, it only provides an API which can be used by angular.js
* If you want to use *AngularJS* because it's a new trend, don't do it. It makes no sense to follow a trend if you don't need it.
* *AngularJS* works pretty well with *Symfony*.
In the end, it completely comes down to the project. One project would benefit from using *AngularJS*, another will only make things more difficult. | AngularJS is a full MVC WebApplication Framework, while jQuery is more to add javascript functionality to particular parts of your website, with less code amount...
Angular is a great solution, but a bit more to learn, while jQuery is a bit less to learn...
It will depend on your skills and what kind of website you want to do...
For big WebApp I would suggest Angular, for just some JS enhencements use jQuery |
27,627,964 | I have a symfony2 application also supporting REST. I would like to hear if it would be a good idea to go over the learning curve of angularjs or stick with jQuery and twig. It seems like twig already has some nice features similar to those in angularjs such as filters and stuff. Also if l use angular it will break symfon's MVC since I will most probably have less views . On the other hand I like the responsiveness of angular and it's like the new trend. Can you list some pros and cons in using angular in this scope?
**Update**
Thank you all for the detailed answers but I'm still missing the part where you say angularjs is not braking the server-side MVC. In a typical back-end MVC we have a bottom-up approach where the controller is communicating with the model to prepare the data to pass to the view. So my PostController will pass a list of Pot objects to the view and using twig I can nicely iterate over them and print their properties. On a typical angular application though, its the other way around. We have a top-down approach where the View starts with nothing and later communicates with the controller to get the data needed (typically in JSON format) to render different parts of the page. | 2014/12/23 | [
"https://Stackoverflow.com/questions/27627964",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/447738/"
] | * *Twig* is server-side, while *AngularJS* is client-side. You can't really compare it
* *AngularJS* is not breaking *Symfony*'s MVC. Symfony just serves another purpose: instead of providing a complete app, it only provides an API which can be used by angular.js
* If you want to use *AngularJS* because it's a new trend, don't do it. It makes no sense to follow a trend if you don't need it.
* *AngularJS* works pretty well with *Symfony*.
In the end, it completely comes down to the project. One project would benefit from using *AngularJS*, another will only make things more difficult. | >
> I have a symfony2 application also supporting REST.
>
>
>
I'll assume you mean you have created RESTful data-driven api in Symfony that uses xml/json or some other data-centric non-html format? If not than I'm confused by this introduction since all websites overlap with REST in a generic way.
>
> I would like to hear if it would be a good idea to go over the learning curve of angularjs or stick with jQuery and twig.
>
>
>
By far the simplest approach (if you are already familiar with Symfony) is to leverage Twig to render your views and pepper it with jQuery for the client-side dynamic/async rendering. Angular adds more conceptual layers than Twig. For instance it duplicates model management in the client. Twig has very low impedance for mapping views to models whereas Angular views will require much more code to manage this mapping. In some cases this decoupling views from data can be a huge boon, if architected correctly. It depends on the needs of your team.
My recommendation would be to implement a small slice of your functionality in both Twig and Angular and keep in mind they have dramatically different runtime considerations and real world mechanics. The most important difference is that Angular ships as client-side only rendering and Twig ships as server-side only rendering. These are fundamentally different concepts. It should be noted there is no reason you can't pre-render Angular on on the server or have the browser render using Twig. These are advanced and non-standard approaches that aren't currently native features of either Twig or Angular, but are entirely possible as optimization steps.
The "snappiness" you attribute to Angular is largely an arbitrary function of specific html + css complexity in a given context and the magnitude of difference between state changes. Wether you put the primary burden of view rendering on the server or client you can properly optimize that solution to be unobtrusive to your user. **The issue is which side of the equation do you want to put your optimization efforts?**
>
> It seems like twig already has some nice features similar to those in angularjs such as filters and stuff. Also if l use angular it will break symfony's MVC since I will most probably have less views.
>
>
>
In general the design of Angular and Symfony are incongruent by analogy with the exception of the semantics of their view rendering, which may be misleading you. The best way to decide which is better for you and your team is to try them both.
You are not breaking Symfony's MVC in the slightest by using Angular. In essence a view is just a representation of data according to a format so whether your server sends JSON data to Angular or having Twig render HTML on the server you're still doing the "V" of Symfony's approach to MVC.
>
> On the other hand I like the responsiveness of angular and it's like the new trend. Can you list some pros and cons in using angular in this scope?
>
>
>
If your user interface is very document/hypertext driven (in other words transparency for search engines matters to you) and you use less than a dozen async calls sitewide you'll almost certainly tend towards twig + jquery.
If your user interfaces require a level of complexity approaching a "desktop" application you'll almost certainly tend towards angular.
Many applications appearing on the market live between the two scenarios outlined. The closer you get to one the more clear your decision will become.
The one thing I can say is that if you have any doubt than you'll probably want to stick with twig/jquery, simply because they are very well understood and proven techniques and require a lot less of a learning curve if you're already building with Symfony. |
27,627,964 | I have a symfony2 application also supporting REST. I would like to hear if it would be a good idea to go over the learning curve of angularjs or stick with jQuery and twig. It seems like twig already has some nice features similar to those in angularjs such as filters and stuff. Also if l use angular it will break symfon's MVC since I will most probably have less views . On the other hand I like the responsiveness of angular and it's like the new trend. Can you list some pros and cons in using angular in this scope?
**Update**
Thank you all for the detailed answers but I'm still missing the part where you say angularjs is not braking the server-side MVC. In a typical back-end MVC we have a bottom-up approach where the controller is communicating with the model to prepare the data to pass to the view. So my PostController will pass a list of Pot objects to the view and using twig I can nicely iterate over them and print their properties. On a typical angular application though, its the other way around. We have a top-down approach where the View starts with nothing and later communicates with the controller to get the data needed (typically in JSON format) to render different parts of the page. | 2014/12/23 | [
"https://Stackoverflow.com/questions/27627964",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/447738/"
] | * *Twig* is server-side, while *AngularJS* is client-side. You can't really compare it
* *AngularJS* is not breaking *Symfony*'s MVC. Symfony just serves another purpose: instead of providing a complete app, it only provides an API which can be used by angular.js
* If you want to use *AngularJS* because it's a new trend, don't do it. It makes no sense to follow a trend if you don't need it.
* *AngularJS* works pretty well with *Symfony*.
In the end, it completely comes down to the project. One project would benefit from using *AngularJS*, another will only make things more difficult. | For me TWIG and TWIG only with js/jQuery/Ajax/Json. Nothing more is needed, really. I don't see any pros of joining Angular with Symfony, while symfony provides everything that is mandatory. Twig is actually HTML on steroids with {{ data }} and {% functions %} that are marvelous and simple, when You prepare data from controller properly.
Next thing that works great with this is CSS grid.
No bootstrap or any frameworks needed to well organize things in proper way.
But!
You or Your team must have skill to prepare good controllers, to not overheat the view. :) |
27,627,964 | I have a symfony2 application also supporting REST. I would like to hear if it would be a good idea to go over the learning curve of angularjs or stick with jQuery and twig. It seems like twig already has some nice features similar to those in angularjs such as filters and stuff. Also if l use angular it will break symfon's MVC since I will most probably have less views . On the other hand I like the responsiveness of angular and it's like the new trend. Can you list some pros and cons in using angular in this scope?
**Update**
Thank you all for the detailed answers but I'm still missing the part where you say angularjs is not braking the server-side MVC. In a typical back-end MVC we have a bottom-up approach where the controller is communicating with the model to prepare the data to pass to the view. So my PostController will pass a list of Pot objects to the view and using twig I can nicely iterate over them and print their properties. On a typical angular application though, its the other way around. We have a top-down approach where the View starts with nothing and later communicates with the controller to get the data needed (typically in JSON format) to render different parts of the page. | 2014/12/23 | [
"https://Stackoverflow.com/questions/27627964",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/447738/"
] | >
> I have a symfony2 application also supporting REST.
>
>
>
I'll assume you mean you have created RESTful data-driven api in Symfony that uses xml/json or some other data-centric non-html format? If not than I'm confused by this introduction since all websites overlap with REST in a generic way.
>
> I would like to hear if it would be a good idea to go over the learning curve of angularjs or stick with jQuery and twig.
>
>
>
By far the simplest approach (if you are already familiar with Symfony) is to leverage Twig to render your views and pepper it with jQuery for the client-side dynamic/async rendering. Angular adds more conceptual layers than Twig. For instance it duplicates model management in the client. Twig has very low impedance for mapping views to models whereas Angular views will require much more code to manage this mapping. In some cases this decoupling views from data can be a huge boon, if architected correctly. It depends on the needs of your team.
My recommendation would be to implement a small slice of your functionality in both Twig and Angular and keep in mind they have dramatically different runtime considerations and real world mechanics. The most important difference is that Angular ships as client-side only rendering and Twig ships as server-side only rendering. These are fundamentally different concepts. It should be noted there is no reason you can't pre-render Angular on on the server or have the browser render using Twig. These are advanced and non-standard approaches that aren't currently native features of either Twig or Angular, but are entirely possible as optimization steps.
The "snappiness" you attribute to Angular is largely an arbitrary function of specific html + css complexity in a given context and the magnitude of difference between state changes. Wether you put the primary burden of view rendering on the server or client you can properly optimize that solution to be unobtrusive to your user. **The issue is which side of the equation do you want to put your optimization efforts?**
>
> It seems like twig already has some nice features similar to those in angularjs such as filters and stuff. Also if l use angular it will break symfony's MVC since I will most probably have less views.
>
>
>
In general the design of Angular and Symfony are incongruent by analogy with the exception of the semantics of their view rendering, which may be misleading you. The best way to decide which is better for you and your team is to try them both.
You are not breaking Symfony's MVC in the slightest by using Angular. In essence a view is just a representation of data according to a format so whether your server sends JSON data to Angular or having Twig render HTML on the server you're still doing the "V" of Symfony's approach to MVC.
>
> On the other hand I like the responsiveness of angular and it's like the new trend. Can you list some pros and cons in using angular in this scope?
>
>
>
If your user interface is very document/hypertext driven (in other words transparency for search engines matters to you) and you use less than a dozen async calls sitewide you'll almost certainly tend towards twig + jquery.
If your user interfaces require a level of complexity approaching a "desktop" application you'll almost certainly tend towards angular.
Many applications appearing on the market live between the two scenarios outlined. The closer you get to one the more clear your decision will become.
The one thing I can say is that if you have any doubt than you'll probably want to stick with twig/jquery, simply because they are very well understood and proven techniques and require a lot less of a learning curve if you're already building with Symfony. | AngularJS is a full MVC WebApplication Framework, while jQuery is more to add javascript functionality to particular parts of your website, with less code amount...
Angular is a great solution, but a bit more to learn, while jQuery is a bit less to learn...
It will depend on your skills and what kind of website you want to do...
For big WebApp I would suggest Angular, for just some JS enhencements use jQuery |
27,627,964 | I have a symfony2 application also supporting REST. I would like to hear if it would be a good idea to go over the learning curve of angularjs or stick with jQuery and twig. It seems like twig already has some nice features similar to those in angularjs such as filters and stuff. Also if l use angular it will break symfon's MVC since I will most probably have less views . On the other hand I like the responsiveness of angular and it's like the new trend. Can you list some pros and cons in using angular in this scope?
**Update**
Thank you all for the detailed answers but I'm still missing the part where you say angularjs is not braking the server-side MVC. In a typical back-end MVC we have a bottom-up approach where the controller is communicating with the model to prepare the data to pass to the view. So my PostController will pass a list of Pot objects to the view and using twig I can nicely iterate over them and print their properties. On a typical angular application though, its the other way around. We have a top-down approach where the View starts with nothing and later communicates with the controller to get the data needed (typically in JSON format) to render different parts of the page. | 2014/12/23 | [
"https://Stackoverflow.com/questions/27627964",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/447738/"
] | >
> I have a symfony2 application also supporting REST.
>
>
>
I'll assume you mean you have created RESTful data-driven api in Symfony that uses xml/json or some other data-centric non-html format? If not than I'm confused by this introduction since all websites overlap with REST in a generic way.
>
> I would like to hear if it would be a good idea to go over the learning curve of angularjs or stick with jQuery and twig.
>
>
>
By far the simplest approach (if you are already familiar with Symfony) is to leverage Twig to render your views and pepper it with jQuery for the client-side dynamic/async rendering. Angular adds more conceptual layers than Twig. For instance it duplicates model management in the client. Twig has very low impedance for mapping views to models whereas Angular views will require much more code to manage this mapping. In some cases this decoupling views from data can be a huge boon, if architected correctly. It depends on the needs of your team.
My recommendation would be to implement a small slice of your functionality in both Twig and Angular and keep in mind they have dramatically different runtime considerations and real world mechanics. The most important difference is that Angular ships as client-side only rendering and Twig ships as server-side only rendering. These are fundamentally different concepts. It should be noted there is no reason you can't pre-render Angular on on the server or have the browser render using Twig. These are advanced and non-standard approaches that aren't currently native features of either Twig or Angular, but are entirely possible as optimization steps.
The "snappiness" you attribute to Angular is largely an arbitrary function of specific html + css complexity in a given context and the magnitude of difference between state changes. Wether you put the primary burden of view rendering on the server or client you can properly optimize that solution to be unobtrusive to your user. **The issue is which side of the equation do you want to put your optimization efforts?**
>
> It seems like twig already has some nice features similar to those in angularjs such as filters and stuff. Also if l use angular it will break symfony's MVC since I will most probably have less views.
>
>
>
In general the design of Angular and Symfony are incongruent by analogy with the exception of the semantics of their view rendering, which may be misleading you. The best way to decide which is better for you and your team is to try them both.
You are not breaking Symfony's MVC in the slightest by using Angular. In essence a view is just a representation of data according to a format so whether your server sends JSON data to Angular or having Twig render HTML on the server you're still doing the "V" of Symfony's approach to MVC.
>
> On the other hand I like the responsiveness of angular and it's like the new trend. Can you list some pros and cons in using angular in this scope?
>
>
>
If your user interface is very document/hypertext driven (in other words transparency for search engines matters to you) and you use less than a dozen async calls sitewide you'll almost certainly tend towards twig + jquery.
If your user interfaces require a level of complexity approaching a "desktop" application you'll almost certainly tend towards angular.
Many applications appearing on the market live between the two scenarios outlined. The closer you get to one the more clear your decision will become.
The one thing I can say is that if you have any doubt than you'll probably want to stick with twig/jquery, simply because they are very well understood and proven techniques and require a lot less of a learning curve if you're already building with Symfony. | For me TWIG and TWIG only with js/jQuery/Ajax/Json. Nothing more is needed, really. I don't see any pros of joining Angular with Symfony, while symfony provides everything that is mandatory. Twig is actually HTML on steroids with {{ data }} and {% functions %} that are marvelous and simple, when You prepare data from controller properly.
Next thing that works great with this is CSS grid.
No bootstrap or any frameworks needed to well organize things in proper way.
But!
You or Your team must have skill to prepare good controllers, to not overheat the view. :) |
613,968 | When you know that your software (not a driver, not part of the os, just an application) will run mostly in a virtualized environment are there strategies to optimize your code and/or compiler settings? Or any guides for what you should and shouldn't do?
This is not about a 0.0x% performance gain but maybe, just maybe there are simple things that will improve performance drastically or things that seem simple but are known to be disastrous in virtualized environments. For example enabling CONFIG\_PARAVIRT in a kernel build is easily done and can boost performance a lot. Now I'm looking for similar things for applications, if there are any.
In my case it will be C++ Code and probably VMWare but I want to keep the question as language/product-agnostic as possible. I wonder if there even are such strategies or if this would be a complete waste of time - after all the concept of virtualization is that you don't have to care too much about it. | 2009/03/05 | [
"https://Stackoverflow.com/questions/613968",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/4833/"
] | The only advice that I can give you is careful use of mlock() / mlockall() .. while looking out for buggy balloon drivers.
For instance, if a Xen guest is booted with 1GB, then ballooned down to 512 MB, its very typical that the privileged domain did NOT look at how much memory the paravirtualized kernel was actually promising to processes (i.e. Committed\_AS). Actually, with Xen, unless this value is placed on Xenbus, the privileged host has no idea what such a balloon will do. I believe this also coincides with KVM, depending upon how the kernel is configured .. but your question presumes that we know nothing about such things :)
So, protect stuff (be careful, but prudent) that simply can not be paged out, always account for the 'sky is falling' scenario.
Likewise, use of posix\_fadvise() / posix\_madvise() to tell the PV kernel just how much you do or do not need buffering is always a good idea.
Beyond that, there's very little that you can do .. since you're talking only to the paravirtualized kernel, which is designed to make processes oblivious to virtualization in the first place.
I don't use KVM much (yet), though I plan to explore it more in the future. However, 90% of the stuff that I have been writing lately is specifically designed to run on paravirtualized Xen guests. Sorry to be a little Xen / C centric, but that's where my experience is and pv\_ops is in mainline (soon also xen-0 ops) :)
Good question, btw :)
**Edit:**
When I said 'careful but prudent' , I meant one step above conservative. If your program allocates some job structure that most functions need, lock it. If your allocating buffers to read huge files, don't lock them .. and be sure to call posix\_fadvise() to let the kernel know you only intend to access it once (if that's the case). Also, be sure to advise the kernel on your use of memory mapped files, especially if they serve to organize concurrency.
In short, help your host kernel manage memory, don't let critical allocated blocks get thrown into dirty paging, don't assume your program is more important than anything else by locking everything it allocates :)
Sorry for the ambiguity. The best phrase I could come up with was 'careful, but prudent'. | My only advice is keep your memory and IO use low if possible.
IO in a VM is pretty slow compared to physical hardware. If you can avoid doing it then avoid it. |
613,968 | When you know that your software (not a driver, not part of the os, just an application) will run mostly in a virtualized environment are there strategies to optimize your code and/or compiler settings? Or any guides for what you should and shouldn't do?
This is not about a 0.0x% performance gain but maybe, just maybe there are simple things that will improve performance drastically or things that seem simple but are known to be disastrous in virtualized environments. For example enabling CONFIG\_PARAVIRT in a kernel build is easily done and can boost performance a lot. Now I'm looking for similar things for applications, if there are any.
In my case it will be C++ Code and probably VMWare but I want to keep the question as language/product-agnostic as possible. I wonder if there even are such strategies or if this would be a complete waste of time - after all the concept of virtualization is that you don't have to care too much about it. | 2009/03/05 | [
"https://Stackoverflow.com/questions/613968",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/4833/"
] | The only advice that I can give you is careful use of mlock() / mlockall() .. while looking out for buggy balloon drivers.
For instance, if a Xen guest is booted with 1GB, then ballooned down to 512 MB, its very typical that the privileged domain did NOT look at how much memory the paravirtualized kernel was actually promising to processes (i.e. Committed\_AS). Actually, with Xen, unless this value is placed on Xenbus, the privileged host has no idea what such a balloon will do. I believe this also coincides with KVM, depending upon how the kernel is configured .. but your question presumes that we know nothing about such things :)
So, protect stuff (be careful, but prudent) that simply can not be paged out, always account for the 'sky is falling' scenario.
Likewise, use of posix\_fadvise() / posix\_madvise() to tell the PV kernel just how much you do or do not need buffering is always a good idea.
Beyond that, there's very little that you can do .. since you're talking only to the paravirtualized kernel, which is designed to make processes oblivious to virtualization in the first place.
I don't use KVM much (yet), though I plan to explore it more in the future. However, 90% of the stuff that I have been writing lately is specifically designed to run on paravirtualized Xen guests. Sorry to be a little Xen / C centric, but that's where my experience is and pv\_ops is in mainline (soon also xen-0 ops) :)
Good question, btw :)
**Edit:**
When I said 'careful but prudent' , I meant one step above conservative. If your program allocates some job structure that most functions need, lock it. If your allocating buffers to read huge files, don't lock them .. and be sure to call posix\_fadvise() to let the kernel know you only intend to access it once (if that's the case). Also, be sure to advise the kernel on your use of memory mapped files, especially if they serve to organize concurrency.
In short, help your host kernel manage memory, don't let critical allocated blocks get thrown into dirty paging, don't assume your program is more important than anything else by locking everything it allocates :)
Sorry for the ambiguity. The best phrase I could come up with was 'careful, but prudent'. | The things that are slow on real hardware are even slower when the system is virtualized. It depends on the virtualization technology being used how much slower they become.
Especially avoid anything that requires I/O with the world outside the virtual environment. Depeding on how things are set up, this includes drawing on the screen, swapping, and disk and network I/O. That's roughly in a decreasing order of importance.
If possible, pretend you're writing for a ten-year-old computer. If your application would work on a 1999 desktop PC, or laptop, it should do OK. |
613,968 | When you know that your software (not a driver, not part of the os, just an application) will run mostly in a virtualized environment are there strategies to optimize your code and/or compiler settings? Or any guides for what you should and shouldn't do?
This is not about a 0.0x% performance gain but maybe, just maybe there are simple things that will improve performance drastically or things that seem simple but are known to be disastrous in virtualized environments. For example enabling CONFIG\_PARAVIRT in a kernel build is easily done and can boost performance a lot. Now I'm looking for similar things for applications, if there are any.
In my case it will be C++ Code and probably VMWare but I want to keep the question as language/product-agnostic as possible. I wonder if there even are such strategies or if this would be a complete waste of time - after all the concept of virtualization is that you don't have to care too much about it. | 2009/03/05 | [
"https://Stackoverflow.com/questions/613968",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/4833/"
] | The only advice that I can give you is careful use of mlock() / mlockall() .. while looking out for buggy balloon drivers.
For instance, if a Xen guest is booted with 1GB, then ballooned down to 512 MB, its very typical that the privileged domain did NOT look at how much memory the paravirtualized kernel was actually promising to processes (i.e. Committed\_AS). Actually, with Xen, unless this value is placed on Xenbus, the privileged host has no idea what such a balloon will do. I believe this also coincides with KVM, depending upon how the kernel is configured .. but your question presumes that we know nothing about such things :)
So, protect stuff (be careful, but prudent) that simply can not be paged out, always account for the 'sky is falling' scenario.
Likewise, use of posix\_fadvise() / posix\_madvise() to tell the PV kernel just how much you do or do not need buffering is always a good idea.
Beyond that, there's very little that you can do .. since you're talking only to the paravirtualized kernel, which is designed to make processes oblivious to virtualization in the first place.
I don't use KVM much (yet), though I plan to explore it more in the future. However, 90% of the stuff that I have been writing lately is specifically designed to run on paravirtualized Xen guests. Sorry to be a little Xen / C centric, but that's where my experience is and pv\_ops is in mainline (soon also xen-0 ops) :)
Good question, btw :)
**Edit:**
When I said 'careful but prudent' , I meant one step above conservative. If your program allocates some job structure that most functions need, lock it. If your allocating buffers to read huge files, don't lock them .. and be sure to call posix\_fadvise() to let the kernel know you only intend to access it once (if that's the case). Also, be sure to advise the kernel on your use of memory mapped files, especially if they serve to organize concurrency.
In short, help your host kernel manage memory, don't let critical allocated blocks get thrown into dirty paging, don't assume your program is more important than anything else by locking everything it allocates :)
Sorry for the ambiguity. The best phrase I could come up with was 'careful, but prudent'. | I've found it to be all about I/O.
VMs typically suck incredibly badly at IO. This makes various things much worse than they would be on real tin.
Swapping is especially a bad killer - it completely wrecks VM performance, even a little, as IO is so slow.
Most implementations have a large amount of IO contention between VMs, I've not seen one which avoids this or handles it sensibly.
So use a ramdisc for temporary files if you can, but don't cause it to swap, because that would be even worse. |
613,968 | When you know that your software (not a driver, not part of the os, just an application) will run mostly in a virtualized environment are there strategies to optimize your code and/or compiler settings? Or any guides for what you should and shouldn't do?
This is not about a 0.0x% performance gain but maybe, just maybe there are simple things that will improve performance drastically or things that seem simple but are known to be disastrous in virtualized environments. For example enabling CONFIG\_PARAVIRT in a kernel build is easily done and can boost performance a lot. Now I'm looking for similar things for applications, if there are any.
In my case it will be C++ Code and probably VMWare but I want to keep the question as language/product-agnostic as possible. I wonder if there even are such strategies or if this would be a complete waste of time - after all the concept of virtualization is that you don't have to care too much about it. | 2009/03/05 | [
"https://Stackoverflow.com/questions/613968",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/4833/"
] | I've found it to be all about I/O.
VMs typically suck incredibly badly at IO. This makes various things much worse than they would be on real tin.
Swapping is especially a bad killer - it completely wrecks VM performance, even a little, as IO is so slow.
Most implementations have a large amount of IO contention between VMs, I've not seen one which avoids this or handles it sensibly.
So use a ramdisc for temporary files if you can, but don't cause it to swap, because that would be even worse. | My only advice is keep your memory and IO use low if possible.
IO in a VM is pretty slow compared to physical hardware. If you can avoid doing it then avoid it. |
613,968 | When you know that your software (not a driver, not part of the os, just an application) will run mostly in a virtualized environment are there strategies to optimize your code and/or compiler settings? Or any guides for what you should and shouldn't do?
This is not about a 0.0x% performance gain but maybe, just maybe there are simple things that will improve performance drastically or things that seem simple but are known to be disastrous in virtualized environments. For example enabling CONFIG\_PARAVIRT in a kernel build is easily done and can boost performance a lot. Now I'm looking for similar things for applications, if there are any.
In my case it will be C++ Code and probably VMWare but I want to keep the question as language/product-agnostic as possible. I wonder if there even are such strategies or if this would be a complete waste of time - after all the concept of virtualization is that you don't have to care too much about it. | 2009/03/05 | [
"https://Stackoverflow.com/questions/613968",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/4833/"
] | I've found it to be all about I/O.
VMs typically suck incredibly badly at IO. This makes various things much worse than they would be on real tin.
Swapping is especially a bad killer - it completely wrecks VM performance, even a little, as IO is so slow.
Most implementations have a large amount of IO contention between VMs, I've not seen one which avoids this or handles it sensibly.
So use a ramdisc for temporary files if you can, but don't cause it to swap, because that would be even worse. | The things that are slow on real hardware are even slower when the system is virtualized. It depends on the virtualization technology being used how much slower they become.
Especially avoid anything that requires I/O with the world outside the virtual environment. Depeding on how things are set up, this includes drawing on the screen, swapping, and disk and network I/O. That's roughly in a decreasing order of importance.
If possible, pretend you're writing for a ten-year-old computer. If your application would work on a 1999 desktop PC, or laptop, it should do OK. |
46,492,764 | There is a question asking whether taking a minimum element from a min-heap is o(logn) time, I thought it was false because it takes constant time because the minimum element is on the top. But the answer is true and the instructor's explanation is that constant time is also of O(logn), it was a wording issue. I am quite confused. So in practice, do we consider constant time a runtime of O(logn)? | 2017/09/29 | [
"https://Stackoverflow.com/questions/46492764",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/8611812/"
] | It is true that anything that is O(1) is O(log n). However, it is not true that everything that is O(log n) is O(1). O is an upper bound, so you can always use a faster-growing function.
Think of it like this:
* Mickey Mouse is a mouse
* All mice are mammals
* Hence, Mickey Mouse is a mammal
* ... but "mice" and "mammals" are not synonymous | It turns out that O notation is just the upper bound of the problem. constant time could be put in any O notation because the upper bound has no limit, maybe even all the way up to n!. Big O notation is not theta. |
46,492,764 | There is a question asking whether taking a minimum element from a min-heap is o(logn) time, I thought it was false because it takes constant time because the minimum element is on the top. But the answer is true and the instructor's explanation is that constant time is also of O(logn), it was a wording issue. I am quite confused. So in practice, do we consider constant time a runtime of O(logn)? | 2017/09/29 | [
"https://Stackoverflow.com/questions/46492764",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/8611812/"
] | It is true that anything that is O(1) is O(log n). However, it is not true that everything that is O(log n) is O(1). O is an upper bound, so you can always use a faster-growing function.
Think of it like this:
* Mickey Mouse is a mouse
* All mice are mammals
* Hence, Mickey Mouse is a mammal
* ... but "mice" and "mammals" are not synonymous | Taking the minimum element from a min-heap is an O(log n) operation because it consists of two steps:
1. Getting the minimum item which, as you point out, is O(1) because it's known to be at the top of the heap.
2. Removing the minimum item. This is O(log n) because it involves moving the last item from the heap to the root, and then sifting it down to readjust the heap.
If you just want to get the minimum item without removing it, then the operation is indeed O(1). But any time you want to modify the heap (and removing the first item certainly qualifies), it's an O(log n) operation.
**Nitpickers note**:
I understand the argument that inserting into a min-heap is, *on average*, an O(1) operation. Whereas that can be true in some situations, the worst case is still O(log n). (Try inserting values into a heap in reverse order. Every insertion is O(log n).) |
488,156 | I have an HP Proliant DL 360 G6. ESXi is installed on the array controlled by the on board RAID controller (P420 I think)
ESXi recognizes the P812 RAID controller but when I put PCI passthrough on it I get a purple screen of death.
My goal is to virtualize an FTP/SAMBA server and give the P812 RAID controller (all 12TB of the MSA60) solely to the FTP/SAMBA VM and nothing else.
I have tried ESXi 5.1 (known to have broken PCI passthrough) and 5.0 (shouldn't have broken passthrough). How do I get this working? | 2013/03/15 | [
"https://serverfault.com/questions/488156",
"https://serverfault.com",
"https://serverfault.com/users/138360/"
] | PCI passthrough is supported on the devices you have. You'll need to update the firmware of all devices. Do this with all devices connected and by running the [**HP Service Pack for ProLiant bootable DVD**](http://h18004.www1.hp.com/products/servers/management/spp/index.html). Your PSOD error may have been resolved in a later build of ESXi. Don't just use what you've downloaded from VMware. You'll want to update to the latest build from the [patch download site](http://www.vmware.com/patchmgr/download.portal?rct=j&q=&esrc=s&source=web&cd=1&ved=0CDMQFjAA&url=http://www.vmware.com/go/downloadpatches&ei=Oy1DUaCWPMHA4AOY0YG4DA&usg=AFQjCNEIHccddkleB6hOSnNbc3Fj3-VlwQ).
I think using the Smart Array P812 controller is a mistake in a passthrough configuration, though. By dedicating it to a single virtual machine, you've added complexity to the setup with no performance or manageability advantage. In addition, you'll need to monitor the storage hardware from the file server VM as well as at the ESXi level.
A better solution would be to use one or both controllers (since the P812 can address your internal disks, too) and create multiple HP logical drives, placing the file server's data in standard VMDK files. With that, you'll have a single management plane.
But ensure all updates are in place before trying the passthrough again. | Why would want to implement the complexity of passing it through. Just configure a datastore and present a VMDK or RDM only to your FTP/SAMBA server. This gives you may more flexibility and will be far more supportable.
That said, by doing this anyway, you're losing a lot of the benefits of virtualisation unless you're going to implement some kind of replication system. |
488,156 | I have an HP Proliant DL 360 G6. ESXi is installed on the array controlled by the on board RAID controller (P420 I think)
ESXi recognizes the P812 RAID controller but when I put PCI passthrough on it I get a purple screen of death.
My goal is to virtualize an FTP/SAMBA server and give the P812 RAID controller (all 12TB of the MSA60) solely to the FTP/SAMBA VM and nothing else.
I have tried ESXi 5.1 (known to have broken PCI passthrough) and 5.0 (shouldn't have broken passthrough). How do I get this working? | 2013/03/15 | [
"https://serverfault.com/questions/488156",
"https://serverfault.com",
"https://serverfault.com/users/138360/"
] | Why would want to implement the complexity of passing it through. Just configure a datastore and present a VMDK or RDM only to your FTP/SAMBA server. This gives you may more flexibility and will be far more supportable.
That said, by doing this anyway, you're losing a lot of the benefits of virtualisation unless you're going to implement some kind of replication system. | I know this post is a few years old, but I think he may have been interested in doing something similar to what I'm planning to do. I have an ESXi 5.5 host (DL380 G6 in fact) running a few essential VMs. The main datastore is supported by the Smart Array P400 ("on-board"). I have an external enclosure (MSA60) that connects directly to the Smart Array P812 (PCI) via Mini SAS cable. The hope is to cut equipment and operation costs by virtualizing a (currently physical) file server. Now, I do see where you are coming from with your recommendation to create another datastore and present it to the VM (in this case the file server), however, WS2012 includes some pretty fancy data management tools. Since I anticipate our storage needs growing over the next few years, I would like to be able to take full advantage of WS2012's Storage Spaces and Pools features. |
488,156 | I have an HP Proliant DL 360 G6. ESXi is installed on the array controlled by the on board RAID controller (P420 I think)
ESXi recognizes the P812 RAID controller but when I put PCI passthrough on it I get a purple screen of death.
My goal is to virtualize an FTP/SAMBA server and give the P812 RAID controller (all 12TB of the MSA60) solely to the FTP/SAMBA VM and nothing else.
I have tried ESXi 5.1 (known to have broken PCI passthrough) and 5.0 (shouldn't have broken passthrough). How do I get this working? | 2013/03/15 | [
"https://serverfault.com/questions/488156",
"https://serverfault.com",
"https://serverfault.com/users/138360/"
] | PCI passthrough is supported on the devices you have. You'll need to update the firmware of all devices. Do this with all devices connected and by running the [**HP Service Pack for ProLiant bootable DVD**](http://h18004.www1.hp.com/products/servers/management/spp/index.html). Your PSOD error may have been resolved in a later build of ESXi. Don't just use what you've downloaded from VMware. You'll want to update to the latest build from the [patch download site](http://www.vmware.com/patchmgr/download.portal?rct=j&q=&esrc=s&source=web&cd=1&ved=0CDMQFjAA&url=http://www.vmware.com/go/downloadpatches&ei=Oy1DUaCWPMHA4AOY0YG4DA&usg=AFQjCNEIHccddkleB6hOSnNbc3Fj3-VlwQ).
I think using the Smart Array P812 controller is a mistake in a passthrough configuration, though. By dedicating it to a single virtual machine, you've added complexity to the setup with no performance or manageability advantage. In addition, you'll need to monitor the storage hardware from the file server VM as well as at the ESXi level.
A better solution would be to use one or both controllers (since the P812 can address your internal disks, too) and create multiple HP logical drives, placing the file server's data in standard VMDK files. With that, you'll have a single management plane.
But ensure all updates are in place before trying the passthrough again. | I know this post is a few years old, but I think he may have been interested in doing something similar to what I'm planning to do. I have an ESXi 5.5 host (DL380 G6 in fact) running a few essential VMs. The main datastore is supported by the Smart Array P400 ("on-board"). I have an external enclosure (MSA60) that connects directly to the Smart Array P812 (PCI) via Mini SAS cable. The hope is to cut equipment and operation costs by virtualizing a (currently physical) file server. Now, I do see where you are coming from with your recommendation to create another datastore and present it to the VM (in this case the file server), however, WS2012 includes some pretty fancy data management tools. Since I anticipate our storage needs growing over the next few years, I would like to be able to take full advantage of WS2012's Storage Spaces and Pools features. |
138,520 | I've asked a professor who I did research with over the summer to write me a letter a recommendation for graduate programs, but he hasn't responded for over a week. I've resent him an email and have received no answer, but a peer who also worked in his lab over summer got an almost immediate response when asking for a letter. We have both done the same research in his lab and known him for the same amount of time. I don't mind if he declines, but I haven't received any word from him. Should I just move on and ask another professor? | 2019/10/14 | [
"https://academia.stackexchange.com/questions/138520",
"https://academia.stackexchange.com",
"https://academia.stackexchange.com/users/115123/"
] | Stop by his office (if in town) or pick up the phone. Just ask him directly if he'll do it or not. A lot of people are not so email/text centric. He'll either say yes or no, but at least you'll know the answer. (And if he says no, just drop it and move on--don't argue.)
Personally, I wouldn't cross off and move on, just because of not responding to email. Especially if he's the best one. He is probably just busy. Or a procrastinator.
Voice or face to face are direct. An email is like a letter. Easy to ignore, to get to it later (which becomes never), etc.
When you do confront him if he says, he's unsure of what you did, offer to give him some bullet points and a BRIEF explanation of what you're going after and key features to emphasize. (In the nature of making his job easier.) | No, contact him again. You gain nothing by "moving on", and you deserve a response.
But let me paint a picture for you.
I'm that professor. I'm very busy and get lots of enquires, both IRL and virtual. I try to answer mails as they arrive, but can't always do so. Busy. Interruptions. Classes. Exams to write. Exams and homework to grade. Lost in thought for a day over a nasty research issue. Busy office hours. So, some thing slip. And the new mails keep coming in - piling up, 30 or more per day. And I don't really have the time or mental energy to scan older mails. So, there are gaps. Or maybe I get a chance to scan it, but your email header doesn't wake me up enough to deal with it.
I also don't think to check my junk box in case a stray word in a valuable mail has triggered the mail bot.
Well, I try to get it right, but I'm not perfect and don't have an assistant to remind me about stuff. Also I'm old and so my mind wanders and my kids have issues of their own that I need to deal with.
But, I'm not a monster, just a human. If you ping me again I'll probably say to myself "oh crap, I shoulda done this last week". And likely deal with it.
If you pop into my office (lucky to catch me) I'll think the same thing and probably apologize. I'm not avoiding you and my job is to help you, even if I'm unwilling to write that letter for you. But I realize you need a definite answer.
If you don't ping me then maybe (just maybe) I'll remember that I "shoulda done that" and catch up, but maybe not.
Ping me. It's ok. Let's see how we can fix it. I owe you that. It's part of why they pay me for this wonderful position. |
21,963 | Element Benders can pass on their abilities genetically. I'm wondering is an avatar that has access to more elements than usual is able to pass on more than their native bending talent. We haven't, to my knowledge much to go on but this family tree.
I doubt we'll see any hard evidence soon (i.e. proof by contradiction), but if there is something I've missed theory wise, it would help answer.
I see two lines of thought on this:
1. Being an avatar is if not hereditary, some how genetic. Some portion of gene could be passed on unlocking non-native bending.
2. Being an avatar is purely spiritual, and cannot be 'passed on' as with normal bending genes. This may imply however that non-avatars can become avatars if they contemplate their navels thoroughly enough...
Which one is correct, or is there a third option? | 2012/08/13 | [
"https://scifi.stackexchange.com/questions/21963",
"https://scifi.stackexchange.com",
"https://scifi.stackexchange.com/users/3804/"
] | I think that from was shown in the shows, being an Avatar is completely spiritual thing. And there is always exactly one Avatar, a reincarnation of the previous Avatars.
Based on that:
1. Being Avatar is not hereditary and Avatar's children can't inherit any of the “extra” powers.
2. You also can't become Avatar through navel-gazing, you have to be born as one and there is only one (living) Avatar at any given time.
All of this is also connected to the origins of bending and possibly energybending, which wasn't explained yet. | No, the avatar can only pass on their native elements to their children. Hope that helps. :) |
21,963 | Element Benders can pass on their abilities genetically. I'm wondering is an avatar that has access to more elements than usual is able to pass on more than their native bending talent. We haven't, to my knowledge much to go on but this family tree.
I doubt we'll see any hard evidence soon (i.e. proof by contradiction), but if there is something I've missed theory wise, it would help answer.
I see two lines of thought on this:
1. Being an avatar is if not hereditary, some how genetic. Some portion of gene could be passed on unlocking non-native bending.
2. Being an avatar is purely spiritual, and cannot be 'passed on' as with normal bending genes. This may imply however that non-avatars can become avatars if they contemplate their navels thoroughly enough...
Which one is correct, or is there a third option? | 2012/08/13 | [
"https://scifi.stackexchange.com/questions/21963",
"https://scifi.stackexchange.com",
"https://scifi.stackexchange.com/users/3804/"
] | I would say number 2:
>
> Being an avatar is purely spiritual, and cannot be 'passed on' as with normal bending genes. This may imply however that non-avatars can become avatars if they contemplate their navels thoroughly enough...
>
>
>
I believe this because as of yet, we have no information that Korra is related to Aang, nor that Roku or any of the other past avatars are related to each other.
Also given the fact that there is a new avatar only at the correct time, ie the old one is always gone before the new one arrives, I would say that 'passing on' the avatar status is spiritual and not genetic.
However, I do not beleive that "non-avatars can become avatars if they contemplate their navels thoroughly enough".
The avatar is a spiritual thing, the avatar is the bridge between the spirit world and the human world.
The [Avatar Wiki](http://avatar.wikia.com/wiki/Avatar) backs me up on this:
>
> The Avatar is the spirit of the planet incarnated in human form
>
>
>
The world is an entity, entities only have one spirit, Therefore there is only one bridge between the spirit world and the earthen world at a time.
One world, one avatar, that is all there can be. | No, the avatar can only pass on their native elements to their children. Hope that helps. :) |
21,963 | Element Benders can pass on their abilities genetically. I'm wondering is an avatar that has access to more elements than usual is able to pass on more than their native bending talent. We haven't, to my knowledge much to go on but this family tree.
I doubt we'll see any hard evidence soon (i.e. proof by contradiction), but if there is something I've missed theory wise, it would help answer.
I see two lines of thought on this:
1. Being an avatar is if not hereditary, some how genetic. Some portion of gene could be passed on unlocking non-native bending.
2. Being an avatar is purely spiritual, and cannot be 'passed on' as with normal bending genes. This may imply however that non-avatars can become avatars if they contemplate their navels thoroughly enough...
Which one is correct, or is there a third option? | 2012/08/13 | [
"https://scifi.stackexchange.com/questions/21963",
"https://scifi.stackexchange.com",
"https://scifi.stackexchange.com/users/3804/"
] | The Avatar is a non-hereditary process. Each Avatar is from a different nation every time they manifest, so there is no genetic process that would be able to account for how it moves from nation to nation in an understandable form. So a bender who is the Avatar, may pass on their primary element (their native one) and that would be it. The rest of their power is derived from a spiritual connection to the elements from their past lives.
* Avatar Roku (Fire Nation, Roku's Island), 82 BSC - 12 BSC
* Avatar Kyoshi (Earth Kingdom, now Kyoshi Island), 312 BSC - 82 BSC
* Avatar Kuruk (Water Tribes, Northern Water Tribe), Unknown - 312 BSC
* Avatar Yangchen (Air Nomads, Western Air Temple), Years unknown
* Unnamed fire Avatar (Fire Nation), Years unknown
*An image of previous avatars, including Aang* | No, the avatar can only pass on their native elements to their children. Hope that helps. :) |
21,963 | Element Benders can pass on their abilities genetically. I'm wondering is an avatar that has access to more elements than usual is able to pass on more than their native bending talent. We haven't, to my knowledge much to go on but this family tree.
I doubt we'll see any hard evidence soon (i.e. proof by contradiction), but if there is something I've missed theory wise, it would help answer.
I see two lines of thought on this:
1. Being an avatar is if not hereditary, some how genetic. Some portion of gene could be passed on unlocking non-native bending.
2. Being an avatar is purely spiritual, and cannot be 'passed on' as with normal bending genes. This may imply however that non-avatars can become avatars if they contemplate their navels thoroughly enough...
Which one is correct, or is there a third option? | 2012/08/13 | [
"https://scifi.stackexchange.com/questions/21963",
"https://scifi.stackexchange.com",
"https://scifi.stackexchange.com/users/3804/"
] | TLDR; No -- because the Avatar doesn't have all the bending genes.
------------------------------------------------------------------
The Avatar does not have the genes to bend all the elements; rather, as shown in [The Legend of Korra](http://avatar.wikia.com/wiki/Beginnings,_Part_1), the Avatar's multi-bending is due to his or her spirit being merged with [Raava, the Spirit of Light](http://avatar.wikia.com/wiki/Raava).
Raava, being a spirit, is able to hold multiple bending arts at once. Human spirits, on the other hand, can only hold one. The merger of the first Avatar, [Wan](http://avatar.wikia.com/wiki/Wan), with Raava allowed him and his reincarnations to bend multiple elements at once.
On the interesting end of things, the state of the Avatar franchise in the first two series had people who self-segregated into nations by the predominant bending ability. This assured that any Avatar was born to a member of a tribe that was known for a type of bending.
From that point, we see that the Avatar will not only be merged with the spirit of Raava, but will also have the genes of a bender in their own right, (incidentally, it's impossible to tell if they're currently expressed, as the Avatar's bending comes from Raava) which can be passed on to their children. They cannot, however, pass on the genes they do not have.
Eventually, however, all the bloodlines will mix as they have begun to in Korra (the nations, now at peace, have started fusing and their people intermixing), and all people will have the potential to be born benders of any single variety. | No, the avatar can only pass on their native elements to their children. Hope that helps. :) |
21,963 | Element Benders can pass on their abilities genetically. I'm wondering is an avatar that has access to more elements than usual is able to pass on more than their native bending talent. We haven't, to my knowledge much to go on but this family tree.
I doubt we'll see any hard evidence soon (i.e. proof by contradiction), but if there is something I've missed theory wise, it would help answer.
I see two lines of thought on this:
1. Being an avatar is if not hereditary, some how genetic. Some portion of gene could be passed on unlocking non-native bending.
2. Being an avatar is purely spiritual, and cannot be 'passed on' as with normal bending genes. This may imply however that non-avatars can become avatars if they contemplate their navels thoroughly enough...
Which one is correct, or is there a third option? | 2012/08/13 | [
"https://scifi.stackexchange.com/questions/21963",
"https://scifi.stackexchange.com",
"https://scifi.stackexchange.com/users/3804/"
] | I would say number 2:
>
> Being an avatar is purely spiritual, and cannot be 'passed on' as with normal bending genes. This may imply however that non-avatars can become avatars if they contemplate their navels thoroughly enough...
>
>
>
I believe this because as of yet, we have no information that Korra is related to Aang, nor that Roku or any of the other past avatars are related to each other.
Also given the fact that there is a new avatar only at the correct time, ie the old one is always gone before the new one arrives, I would say that 'passing on' the avatar status is spiritual and not genetic.
However, I do not beleive that "non-avatars can become avatars if they contemplate their navels thoroughly enough".
The avatar is a spiritual thing, the avatar is the bridge between the spirit world and the human world.
The [Avatar Wiki](http://avatar.wikia.com/wiki/Avatar) backs me up on this:
>
> The Avatar is the spirit of the planet incarnated in human form
>
>
>
The world is an entity, entities only have one spirit, Therefore there is only one bridge between the spirit world and the earthen world at a time.
One world, one avatar, that is all there can be. | I think that from was shown in the shows, being an Avatar is completely spiritual thing. And there is always exactly one Avatar, a reincarnation of the previous Avatars.
Based on that:
1. Being Avatar is not hereditary and Avatar's children can't inherit any of the “extra” powers.
2. You also can't become Avatar through navel-gazing, you have to be born as one and there is only one (living) Avatar at any given time.
All of this is also connected to the origins of bending and possibly energybending, which wasn't explained yet. |
21,963 | Element Benders can pass on their abilities genetically. I'm wondering is an avatar that has access to more elements than usual is able to pass on more than their native bending talent. We haven't, to my knowledge much to go on but this family tree.
I doubt we'll see any hard evidence soon (i.e. proof by contradiction), but if there is something I've missed theory wise, it would help answer.
I see two lines of thought on this:
1. Being an avatar is if not hereditary, some how genetic. Some portion of gene could be passed on unlocking non-native bending.
2. Being an avatar is purely spiritual, and cannot be 'passed on' as with normal bending genes. This may imply however that non-avatars can become avatars if they contemplate their navels thoroughly enough...
Which one is correct, or is there a third option? | 2012/08/13 | [
"https://scifi.stackexchange.com/questions/21963",
"https://scifi.stackexchange.com",
"https://scifi.stackexchange.com/users/3804/"
] | The Avatar is a non-hereditary process. Each Avatar is from a different nation every time they manifest, so there is no genetic process that would be able to account for how it moves from nation to nation in an understandable form. So a bender who is the Avatar, may pass on their primary element (their native one) and that would be it. The rest of their power is derived from a spiritual connection to the elements from their past lives.
* Avatar Roku (Fire Nation, Roku's Island), 82 BSC - 12 BSC
* Avatar Kyoshi (Earth Kingdom, now Kyoshi Island), 312 BSC - 82 BSC
* Avatar Kuruk (Water Tribes, Northern Water Tribe), Unknown - 312 BSC
* Avatar Yangchen (Air Nomads, Western Air Temple), Years unknown
* Unnamed fire Avatar (Fire Nation), Years unknown
*An image of previous avatars, including Aang* | I think that from was shown in the shows, being an Avatar is completely spiritual thing. And there is always exactly one Avatar, a reincarnation of the previous Avatars.
Based on that:
1. Being Avatar is not hereditary and Avatar's children can't inherit any of the “extra” powers.
2. You also can't become Avatar through navel-gazing, you have to be born as one and there is only one (living) Avatar at any given time.
All of this is also connected to the origins of bending and possibly energybending, which wasn't explained yet. |
21,963 | Element Benders can pass on their abilities genetically. I'm wondering is an avatar that has access to more elements than usual is able to pass on more than their native bending talent. We haven't, to my knowledge much to go on but this family tree.
I doubt we'll see any hard evidence soon (i.e. proof by contradiction), but if there is something I've missed theory wise, it would help answer.
I see two lines of thought on this:
1. Being an avatar is if not hereditary, some how genetic. Some portion of gene could be passed on unlocking non-native bending.
2. Being an avatar is purely spiritual, and cannot be 'passed on' as with normal bending genes. This may imply however that non-avatars can become avatars if they contemplate their navels thoroughly enough...
Which one is correct, or is there a third option? | 2012/08/13 | [
"https://scifi.stackexchange.com/questions/21963",
"https://scifi.stackexchange.com",
"https://scifi.stackexchange.com/users/3804/"
] | TLDR; No -- because the Avatar doesn't have all the bending genes.
------------------------------------------------------------------
The Avatar does not have the genes to bend all the elements; rather, as shown in [The Legend of Korra](http://avatar.wikia.com/wiki/Beginnings,_Part_1), the Avatar's multi-bending is due to his or her spirit being merged with [Raava, the Spirit of Light](http://avatar.wikia.com/wiki/Raava).
Raava, being a spirit, is able to hold multiple bending arts at once. Human spirits, on the other hand, can only hold one. The merger of the first Avatar, [Wan](http://avatar.wikia.com/wiki/Wan), with Raava allowed him and his reincarnations to bend multiple elements at once.
On the interesting end of things, the state of the Avatar franchise in the first two series had people who self-segregated into nations by the predominant bending ability. This assured that any Avatar was born to a member of a tribe that was known for a type of bending.
From that point, we see that the Avatar will not only be merged with the spirit of Raava, but will also have the genes of a bender in their own right, (incidentally, it's impossible to tell if they're currently expressed, as the Avatar's bending comes from Raava) which can be passed on to their children. They cannot, however, pass on the genes they do not have.
Eventually, however, all the bloodlines will mix as they have begun to in Korra (the nations, now at peace, have started fusing and their people intermixing), and all people will have the potential to be born benders of any single variety. | I think that from was shown in the shows, being an Avatar is completely spiritual thing. And there is always exactly one Avatar, a reincarnation of the previous Avatars.
Based on that:
1. Being Avatar is not hereditary and Avatar's children can't inherit any of the “extra” powers.
2. You also can't become Avatar through navel-gazing, you have to be born as one and there is only one (living) Avatar at any given time.
All of this is also connected to the origins of bending and possibly energybending, which wasn't explained yet. |
21,963 | Element Benders can pass on their abilities genetically. I'm wondering is an avatar that has access to more elements than usual is able to pass on more than their native bending talent. We haven't, to my knowledge much to go on but this family tree.
I doubt we'll see any hard evidence soon (i.e. proof by contradiction), but if there is something I've missed theory wise, it would help answer.
I see two lines of thought on this:
1. Being an avatar is if not hereditary, some how genetic. Some portion of gene could be passed on unlocking non-native bending.
2. Being an avatar is purely spiritual, and cannot be 'passed on' as with normal bending genes. This may imply however that non-avatars can become avatars if they contemplate their navels thoroughly enough...
Which one is correct, or is there a third option? | 2012/08/13 | [
"https://scifi.stackexchange.com/questions/21963",
"https://scifi.stackexchange.com",
"https://scifi.stackexchange.com/users/3804/"
] | TLDR; No -- because the Avatar doesn't have all the bending genes.
------------------------------------------------------------------
The Avatar does not have the genes to bend all the elements; rather, as shown in [The Legend of Korra](http://avatar.wikia.com/wiki/Beginnings,_Part_1), the Avatar's multi-bending is due to his or her spirit being merged with [Raava, the Spirit of Light](http://avatar.wikia.com/wiki/Raava).
Raava, being a spirit, is able to hold multiple bending arts at once. Human spirits, on the other hand, can only hold one. The merger of the first Avatar, [Wan](http://avatar.wikia.com/wiki/Wan), with Raava allowed him and his reincarnations to bend multiple elements at once.
On the interesting end of things, the state of the Avatar franchise in the first two series had people who self-segregated into nations by the predominant bending ability. This assured that any Avatar was born to a member of a tribe that was known for a type of bending.
From that point, we see that the Avatar will not only be merged with the spirit of Raava, but will also have the genes of a bender in their own right, (incidentally, it's impossible to tell if they're currently expressed, as the Avatar's bending comes from Raava) which can be passed on to their children. They cannot, however, pass on the genes they do not have.
Eventually, however, all the bloodlines will mix as they have begun to in Korra (the nations, now at peace, have started fusing and their people intermixing), and all people will have the potential to be born benders of any single variety. | I would say number 2:
>
> Being an avatar is purely spiritual, and cannot be 'passed on' as with normal bending genes. This may imply however that non-avatars can become avatars if they contemplate their navels thoroughly enough...
>
>
>
I believe this because as of yet, we have no information that Korra is related to Aang, nor that Roku or any of the other past avatars are related to each other.
Also given the fact that there is a new avatar only at the correct time, ie the old one is always gone before the new one arrives, I would say that 'passing on' the avatar status is spiritual and not genetic.
However, I do not beleive that "non-avatars can become avatars if they contemplate their navels thoroughly enough".
The avatar is a spiritual thing, the avatar is the bridge between the spirit world and the human world.
The [Avatar Wiki](http://avatar.wikia.com/wiki/Avatar) backs me up on this:
>
> The Avatar is the spirit of the planet incarnated in human form
>
>
>
The world is an entity, entities only have one spirit, Therefore there is only one bridge between the spirit world and the earthen world at a time.
One world, one avatar, that is all there can be. |
21,963 | Element Benders can pass on their abilities genetically. I'm wondering is an avatar that has access to more elements than usual is able to pass on more than their native bending talent. We haven't, to my knowledge much to go on but this family tree.
I doubt we'll see any hard evidence soon (i.e. proof by contradiction), but if there is something I've missed theory wise, it would help answer.
I see two lines of thought on this:
1. Being an avatar is if not hereditary, some how genetic. Some portion of gene could be passed on unlocking non-native bending.
2. Being an avatar is purely spiritual, and cannot be 'passed on' as with normal bending genes. This may imply however that non-avatars can become avatars if they contemplate their navels thoroughly enough...
Which one is correct, or is there a third option? | 2012/08/13 | [
"https://scifi.stackexchange.com/questions/21963",
"https://scifi.stackexchange.com",
"https://scifi.stackexchange.com/users/3804/"
] | TLDR; No -- because the Avatar doesn't have all the bending genes.
------------------------------------------------------------------
The Avatar does not have the genes to bend all the elements; rather, as shown in [The Legend of Korra](http://avatar.wikia.com/wiki/Beginnings,_Part_1), the Avatar's multi-bending is due to his or her spirit being merged with [Raava, the Spirit of Light](http://avatar.wikia.com/wiki/Raava).
Raava, being a spirit, is able to hold multiple bending arts at once. Human spirits, on the other hand, can only hold one. The merger of the first Avatar, [Wan](http://avatar.wikia.com/wiki/Wan), with Raava allowed him and his reincarnations to bend multiple elements at once.
On the interesting end of things, the state of the Avatar franchise in the first two series had people who self-segregated into nations by the predominant bending ability. This assured that any Avatar was born to a member of a tribe that was known for a type of bending.
From that point, we see that the Avatar will not only be merged with the spirit of Raava, but will also have the genes of a bender in their own right, (incidentally, it's impossible to tell if they're currently expressed, as the Avatar's bending comes from Raava) which can be passed on to their children. They cannot, however, pass on the genes they do not have.
Eventually, however, all the bloodlines will mix as they have begun to in Korra (the nations, now at peace, have started fusing and their people intermixing), and all people will have the potential to be born benders of any single variety. | The Avatar is a non-hereditary process. Each Avatar is from a different nation every time they manifest, so there is no genetic process that would be able to account for how it moves from nation to nation in an understandable form. So a bender who is the Avatar, may pass on their primary element (their native one) and that would be it. The rest of their power is derived from a spiritual connection to the elements from their past lives.
* Avatar Roku (Fire Nation, Roku's Island), 82 BSC - 12 BSC
* Avatar Kyoshi (Earth Kingdom, now Kyoshi Island), 312 BSC - 82 BSC
* Avatar Kuruk (Water Tribes, Northern Water Tribe), Unknown - 312 BSC
* Avatar Yangchen (Air Nomads, Western Air Temple), Years unknown
* Unnamed fire Avatar (Fire Nation), Years unknown
*An image of previous avatars, including Aang* |
72,325 | >
> Many an opportunity is lost because a man is out looking for four-leaf
> clovers.
>
>
>
I have no idea what the quotation means. Is there any special meaning about four-leaf clovers that I may be unaware of? | 2012/06/23 | [
"https://english.stackexchange.com/questions/72325",
"https://english.stackexchange.com",
"https://english.stackexchange.com/users/13711/"
] | My guess is: success comes more from conscientiousness (seizing opportunities) than from luck (four-leaf clovers). Or: don't rely on luck, take advantage of opportunities. | The only reference I can find right now says that the ratio of three-leaf to four-leaf clovers is ~10,000 to 1. I would interpret that saying as meaning that you're likely to miss real opportunities if you spend (waste) your time looking for a rare item to bring you good luck. |
72,325 | >
> Many an opportunity is lost because a man is out looking for four-leaf
> clovers.
>
>
>
I have no idea what the quotation means. Is there any special meaning about four-leaf clovers that I may be unaware of? | 2012/06/23 | [
"https://english.stackexchange.com/questions/72325",
"https://english.stackexchange.com",
"https://english.stackexchange.com/users/13711/"
] | My guess is: success comes more from conscientiousness (seizing opportunities) than from luck (four-leaf clovers). Or: don't rely on luck, take advantage of opportunities. | It means valuable opportunities are easily squandered by spending too much time searching for things that are difficult (or impossible) to find.
For example, chasing after a scholarship from NC State with single-minded intensity may cause someone to miss the fact that they've been already been accepted by ECU.
IDK if that helped; I hope it did. :) |
72,325 | >
> Many an opportunity is lost because a man is out looking for four-leaf
> clovers.
>
>
>
I have no idea what the quotation means. Is there any special meaning about four-leaf clovers that I may be unaware of? | 2012/06/23 | [
"https://english.stackexchange.com/questions/72325",
"https://english.stackexchange.com",
"https://english.stackexchange.com/users/13711/"
] | The only reference I can find right now says that the ratio of three-leaf to four-leaf clovers is ~10,000 to 1. I would interpret that saying as meaning that you're likely to miss real opportunities if you spend (waste) your time looking for a rare item to bring you good luck. | It means valuable opportunities are easily squandered by spending too much time searching for things that are difficult (or impossible) to find.
For example, chasing after a scholarship from NC State with single-minded intensity may cause someone to miss the fact that they've been already been accepted by ECU.
IDK if that helped; I hope it did. :) |
263,365 | It's for an RPG worldbuilding blog I'd like to make. | 2015/07/29 | [
"https://english.stackexchange.com/questions/263365",
"https://english.stackexchange.com",
"https://english.stackexchange.com/users/131069/"
] | [stage](https://en.wiktionary.org/wiki/stage)
---------------------------------------------
>
> * A platform, generally elevated, upon which show performances or other public events are given.
> * A degree of advancement in a journey; one of several portions into which a road or course is marked off; the distance between two places of rest on a road
> * *(video games)* A level; one of the sequential areas making up the game.
>
>
>
Consider the term "to set the stage" in a broader context than that of a theater. Shakespeare often used this term for when narrators introduce plays. RPGs are games of storytelling and are quite similar to plays, and they often use theatrical terms. | Here are some ideas to get you thinking about what works with your project:
Environment, locale, mise en scène, backdrop, curtain opening, tableau (this one has a fun plural -- tableaux), country, chessboard, playmat, gameboard, terrain, land. |
58,035 | Assalamualaikum.i am a student.I am currently preparing for an exam.It is very tough for me to pass the exam and obtain a good rank.But I am trying my level best and studying very sincerely.Can you suggest me any Dua which will be answered quickly by Allah and which is such effective that I will be able to pass the exam?? | 2020/02/21 | [
"https://islam.stackexchange.com/questions/58035",
"https://islam.stackexchange.com",
"https://islam.stackexchange.com/users/36130/"
] | Calm down. Your O and A levels will do nothing to your life. What's written is written. If you are meant to live in a lesser house, drive a lesser car, then your A\* in your exam can't change it.
Finally, the dua, doesn't have to be specific words. Just ask Allah to make it easy for you.
For an Arabic dua in particular, read this:
>
> اللَّهُمَّ لاَ سَهْلاً إِلّاَ مَا جَعَلّتَهٌ سَهْلاً وَأَنّتَ تَجّعَلَ الحَزَنَ إِذَا شِئتَ سَهْلاً (See [here](https://sunnah.com/hisn/140) with transliteration)
>
>
> | You can make dua but it may not be accepted/what you ask for may not be given to you. Your dua will be acknowledged. Focus on your exams but also in your duties in Islam. Praying and whatnot. |
247,957 | Just wondering if everything is normal on my cell phone... It's an LG and they stopped updating, but I don't remember this behavior before... | 2022/08/10 | [
"https://android.stackexchange.com/questions/247957",
"https://android.stackexchange.com",
"https://android.stackexchange.com/users/377494/"
] | You could, potentially, manage your traffic by following a couple of rules:
1. When you are on the move, i.e. using mobile data
a. Turn **OFF** Wi-Fi
b. Turn **OFF** VPN
c. **Enable** Mobile Data
2. When you are expecting to use an unsecured WiFi *(e.g. Internet Café, Airport)*
a. **DISABLE** Mobile Data
b. Turn **ON** VPN
c. Turn **ON** Wi-Fi
The order that these are done in is important. This does, *of course*, assume that you do trust your carriers internet access to be *reasonably* private.
You could potentially automate with something like If This Then That or you may be able to find an app that lets you have a button to toggle these settings. | There is an issue here that NordVPN do not recognise. From Jan - Oct this year I had adequate mobile data. In November my mobile data consumption rocketed up. In December the NordVPN app consumed most of my mobile data allowance, so I turned mobile data off. I contacted NordVPN, they have not got a clue. To me something in the App is consuming data and this error has emerged in Q4. I'm going to get myself another VPN that pays a bit more attention to it's customer. I would recommend that you do the same.
When I look at the mobile data usage log for Nov and Dec, NordVPN is the number one mobile data consumer. |
116,757 | How can I remove these stains from my ladder? Do I need some sort of special cleaner or would some regular household cleaner work as well?
[](https://i.stack.imgur.com/KzQz7.jpg) | 2017/06/18 | [
"https://diy.stackexchange.com/questions/116757",
"https://diy.stackexchange.com",
"https://diy.stackexchange.com/users/71001/"
] | Don't waste your time. Trying to prevent a ladder from being covered in paint is like trying to keep a war hero's uniform from getting covered in medals. *Exactly like that, in fact.*
Paint stains means the ladder has been doing useful work. When did that fall out of fashion?
Assuming it is latex paint, your best bet is to catch it right away with soap and water. Soaking it in water helps soften the latex paint if it's fairly new. For oils and 2-part paints, fuggedaboutit. | Use warm water with floor cleaning detergent and a stiff scrub brush to scrub paint out of the grooves. If you can't get it all out, just accept it.
Do **not** use paint remover or solvents. These will damage the rubber treads. |
14,104 | What is the preferred method for organizing CSS that is only used by a single HTML page. Should I put the CSS in:
* a section in the HTML doc?
* a CSS file associated with the HTML doc? eg: contacts.html, contacts.css
* a master CSS file and organize it into sections indicated with header comments. | 2011/05/20 | [
"https://webmasters.stackexchange.com/questions/14104",
"https://webmasters.stackexchange.com",
"https://webmasters.stackexchange.com/users/5348/"
] | I'm assuming that there are other pages which use the master CSS file you mention. In that case I think the third option is best. I'm also assuming that this single HTML file also uses CSS from that master file.
The trouble with the first option is that it's not the way things are usually done, and so in the future when either you or someone else wants to change things it may take you/them a while to find out where the CSS is.
The advantage of the third option is if you want to change the way this contacts.html file looks you only have to go and look in one place - the master file. The CSS that applies to that page and others is there, and the CSS that applies only to that page is there. It also helps with performance because if visitors to your site have already visited the other pages then they have that file cached and they don't need to load it again. | If the CSS directives affect only one HTML document, it only makes sense to keep the directives in the document.
From a maintenance perspective, if the document's structure or content changes the CSS directives may need to change as well and, from a performance perspective, it does not make sense to force users to download directives for a single document when they visit other pages on the site. |
491,068 | What is the use of the NRST pin in STM32F401RTC microcontroller. I am using the SWD interface to program and debug flash memory of the controller. I am finding NRST pins in both microcontroller as well as stlink debugger.
**I am confused, what is the use of NRST pins? Is it used to reset the program which we flash and allow us to program it again? And why is a capacitor connected on the outer side of the pin and to ground?**
[](https://i.stack.imgur.com/7e4Jl.png)
**What is the use of it in microcontroller and Stlink? How does it work?**
I checked in Google. The explanation given was too technical, so kindly explain to me in simple terms. | 2020/04/04 | [
"https://electronics.stackexchange.com/questions/491068",
"https://electronics.stackexchange.com",
"https://electronics.stackexchange.com/users/237628/"
] | >
> Is it used to reset the program which we flash and allow us to program
> it again?
>
>
>
It seems you are confused about what reset actually resets. **It does not "reset the program", it resets the MCU**. The content of flash is not changed, so previously written program is still available.
Specifically, while NRST pin is connected to the ground the MCU stays in "reset state", i.e. it does not do anything, the clocks are stopped and the program that is already flashed is not running.
When you disconnect NRST pin from the ground (release the button) the internal pull-up resistor (marked RPU on the schematics) applies VDD voltage to it, which eventually flips Schmitt trigger and brings MCU out of reset state, at which point it starts executing the program at reset vector.
>
> why is a capacitor connected on the outer side of the pin and to ground?
>
>
>
The capacitor is there to provide some EMS protection and avoid parasitic resets.
>
> What is the use of it in microcontroller and Stlink? How does it work?
>
>
>
Usually the program at reset vector is a bootloader, which will either detect an attempt to upload new program (via USB, CAN, Serial etc. channels) or simply pass execution to the old program already in flash. It is the second case that can be interpreted as "program reset", since the program indeed begins execution from start. However the important difference is that NRST does much more than simple program restart, for example it resets all the MCU registers to their default states.
Note that in your particular case (using SWD interface for programming) the NRST pin is not actually useful, since SWD completely bypasses bootloader and can reset and flash MCU directly. It is only if your program reconfigured SWD pins as regular GPIO then you need hardware reset to flash a new one (remember that NRST resets all registers to default states, including pin configuration). ST-LINK usually uses software reset, however if it does not work you can go into setup interface and change this to hardware.
In short, NRST pin is used to activate bootloader when you need to flash new program using one of the communication channels and to reset MCU to default state when you want to flash new program using SWD interface and SWD pins are not available. | It resets the MCU. In order to flash the MCU, the ST-LINK resets and then sends the program through SWD. It should be self explanatory that MCU can't run the program and being flashed at the same time. So how to stop the CPU execution and invoke the bootloader? The first step is to reset it. |
6,965,210 | Is there any way to save crash log while apps is crashed and also apps is launched at that time Mail Dialogue is display to send the mail with that crash log???? so please tell me any link or any idea to develop this functionality in iPhone...
Thanks in advance | 2011/08/06 | [
"https://Stackoverflow.com/questions/6965210",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/913339/"
] | I recommend [QuincyKit](http://quincykit.net/). It is open source and you'll have to setup your own server to collect crash logs. | Crittercism worked for me
It can be implemented in few minutes, which is easy and great.
Crittercism supports instant crash reporting to your mail(setting up server is not required)
Detailed report generation which includes the line number where the crash occurred.
Following links helped me:
[Crittercism](http://www.youtube.com/watch?v=ONp2S9USMNY)
**Note:** Adding DSYM file is recommended(which is responsible for showing the exact line number where crash occurred)
See [this](http://www.youtube.com/watch?v=i2hv35MisgM) |
6,965,210 | Is there any way to save crash log while apps is crashed and also apps is launched at that time Mail Dialogue is display to send the mail with that crash log???? so please tell me any link or any idea to develop this functionality in iPhone...
Thanks in advance | 2011/08/06 | [
"https://Stackoverflow.com/questions/6965210",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/913339/"
] | You don't really need any additional SDK's to view the crash raports. Apple gives you this functionality in their "iTunes Connect" portal. Here is how to access it:
* Log in to [iTunesConnect](https://itunesconnect.apple.com)
* go to "Manage Your Applications"
* choose your application, by clicking on it's name.
* click "View details" button under the Versions table.
* click "Crash Reports" link
* if you don't have reports yet, press "refresh"
That's it.
Hope that helps. | Crittercism worked for me
It can be implemented in few minutes, which is easy and great.
Crittercism supports instant crash reporting to your mail(setting up server is not required)
Detailed report generation which includes the line number where the crash occurred.
Following links helped me:
[Crittercism](http://www.youtube.com/watch?v=ONp2S9USMNY)
**Note:** Adding DSYM file is recommended(which is responsible for showing the exact line number where crash occurred)
See [this](http://www.youtube.com/watch?v=i2hv35MisgM) |
18,006,071 | I am synthesizing some multiplication units in verilog and I was wondering if you generally get better results in terms of area/power savings if you implement your own CSA using booth encoding when multplying or if you just use the \* symbol and let the synthesis tool take care of the problem for you?
Thank you! | 2013/08/01 | [
"https://Stackoverflow.com/questions/18006071",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/688463/"
] | Generally, I tend to trust the compiler tools I use and don't fret so much about the results as long as they meet my timing and area budgets.
That said, with multipliers that need to run at fast speeds I find I get better results (in DC, at least) if I create a Verilog module containing the multiply (`*`) and a retiming register or two, and push down into this module to synthesise it before popping up to toplevel synthesis. It seems as if the compiler gets 'distracted' by other timing paths if you try to do everything at once, so making it focus on a multiplier that you know is going to be tricky seems to help. | I agree with @Marty in that I would use `*`. I have previously built my own low power adder structures, which then ran in to problems when the design shifted process/had to be run at a higher frequency. Hard coded architectures like this remove quite a bit of portability from the code.
Using the directives is nice in trials to see the different size (area) of architectures, but I leave the decision to the synthesis tool to make the best call based on the timing constraints and available area. I am not sure how power aware the tools are by default. Previously we ended up getting an extra license which added a lot of power aware knowledge to the synthesis. |
18,006,071 | I am synthesizing some multiplication units in verilog and I was wondering if you generally get better results in terms of area/power savings if you implement your own CSA using booth encoding when multplying or if you just use the \* symbol and let the synthesis tool take care of the problem for you?
Thank you! | 2013/08/01 | [
"https://Stackoverflow.com/questions/18006071",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/688463/"
] | Generally, I tend to trust the compiler tools I use and don't fret so much about the results as long as they meet my timing and area budgets.
That said, with multipliers that need to run at fast speeds I find I get better results (in DC, at least) if I create a Verilog module containing the multiply (`*`) and a retiming register or two, and push down into this module to synthesise it before popping up to toplevel synthesis. It seems as if the compiler gets 'distracted' by other timing paths if you try to do everything at once, so making it focus on a multiplier that you know is going to be tricky seems to help. | You have this question tagged with "FPGA." If your target device is an FPGA then it may be advisable to use FPGA's multiplier megafunction (don't remember what Xilinx calls it these days.)
This way, you will be sure that the tool utilizes the whatever internal hardware structure that you intend to use irrespective of synthesizer tool. You will be sure to get an optimum solution that is also predictable from a timing and latency standpoint.
Additionally, you don't have to test it for all the corner cases, especially important if you are doing signed multiplication and what kind of coding guidelines you follow. |
11,315,966 | I decided to try to my hand at this, and have had a somewhat frustrating day. I've been downloading and installing all the developement software, but Eclipse has given me lots of trouble. I've figured most of it out, but have another problem. For some reason the Google APIs are not installing :
[bigger image](https://i.stack.imgur.com/79bEa.png)
Why is this? They are important right? I'm currently using a book for total beginners, and I pretty much have no idea what I'm doing as of now. Thank you SO MUCH for any help and your time viewing this.
(I am running Eclipse Indigo) | 2012/07/03 | [
"https://Stackoverflow.com/questions/11315966",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/1499494/"
] | As you can see in the status bar, they are installing fine. Just the *Google TV* is not compatible with your environment. If you want to go for smartphone app development, then either the "pure" Android APIs or the Google APIs (including Google Maps) are fine for the beginning. | The Google APIs aren't 100% mission critical to developing an Android application, but do contain classes and methods for using most of the Google features (Gmail, Google Maps, etc.).
You should be fine with just the Android APIs until you get into the more advanced functionality of the platform. |
96,520 | A fixed pitch propeller is only good for aircraft that do around 100kts because the angle of attack on the propeller decreases as the forward airspeed of the aircraft increases, limiting the thrust available. Variable pitch propellers overcome this allowing the angle of attack to remain optimal at speed thus allowing faster cruise speeds.
However the pitch angle of the bypass stage of a turbofan is fixed but yet they do not seem limited by the same problem affecting a fixed pitch propeller. Turbofans provide sufficient thrust at take-off (very low forward speed) as well as much higher cruise speeds.
I'm trying unsuccessfully to understand the physics of this or more specifically: If the pitch of the turbofan is set optimally for cruise, why does it not stall at take-off due to a very high angle of attack? Conversely, if the pitch was set for high thrust at take-off (or some lower speed setting), shouldn't the angle of attack reduce as speed increases thereby limiting cruise speed attainable? | 2022/12/20 | [
"https://aviation.stackexchange.com/questions/96520",
"https://aviation.stackexchange.com",
"https://aviation.stackexchange.com/users/66799/"
] | [](https://i.stack.imgur.com/TYq0t.png)
A large part of this is provided by the turbofan inlet design. Above pic is from Aircraft Gas Turbines by C.J.Houtman and was used earlier in [this answer](https://aviation.stackexchange.com/a/73029/21091): the inlet shape slows the incoming air down at cruise speed, and trades velocity in for pressure.
The variables:
* At TakeOff thrust needs to be maximal, the fan blades need to suck all the air in, and the fan does so at maximum RPM.
* At cruise thrust is lower, the RPM is lower, and the air inflow is slowed down.
Indeed the variation in thrust requirements and airspeed create quite a difficult set of operational circumstances to tune, care must be taken to prevent stalling of the blade tips, and stalling of the inflowing air-stream around the inlet nose at lower velocities, which is why the inlet is optimised for these lower airspeeds.
Propellers operate at lower airspeeds than turbofans, and operate at constant RPM with variable blade AoA for optimal thrust efficiency. Turbofans would also benefit from variable blade AoA, and efforts have been made to develop them, but the cost/gain ratio seems to be prohibitive for now. | The AoA of the fan blades varies throughout the speed range, very similar in principle to a fixed pitch propeller. However, the change in AoA also depends on the propulsive efficiency of the engine.
This variation in AoA is determined by the change in **"down" wash** at the fan blades (think of the fan blade like a wing). This downwash is for to two reasons: forward speed (TAS), and the inherent downwash (jet-wash) due to the production of lift (thrust) itself. On a turboprop engine with high propulsive efficiency, this latter downwash is low, but is relatively high on turbofans (and is even higher on turbojets). The net downwash as experienced by the fan blades is a sum of the two.
---
When a turbofan is operating on ground at zero TAS, the effective TAS at the fan blades is quite high. This is due to the aforementioned downwash at the fan blades due to the production of thrust itself. This downwash reduces the effective AoA of the blades enough to prevent it from stalling. As aircraft TAS increases, the net downwash increases, causing the effective AoA of the blades to decrease.
However, on a turboprop with a much higher propulsive efficiency, the initial downwash (due to thrust production) is relatively low, and it's influence on the effective AoA is much less. When the aircraft TAS increases through the same speed range as in the turbofan case, the percentage increase in the net downwash is much higher, and so is the change in AoA. The only way to maintain a reasonable AoA is through the use of variable pitch propellers.
In the turbofan case, the change in AoA as the speed increased was significant, but still low enough - a variable pitch mechanism would be able to provide much less improvement, meaning that it's use is not feasible.
If you find this difficult to accept, think of the extreme case: if the initial downwash was infinite (blade pitch would be 90°), an increase in TAS through any speed range would have no effect on the AoA, and so a variable pitch system will be absolutely useless in this case. |
96,520 | A fixed pitch propeller is only good for aircraft that do around 100kts because the angle of attack on the propeller decreases as the forward airspeed of the aircraft increases, limiting the thrust available. Variable pitch propellers overcome this allowing the angle of attack to remain optimal at speed thus allowing faster cruise speeds.
However the pitch angle of the bypass stage of a turbofan is fixed but yet they do not seem limited by the same problem affecting a fixed pitch propeller. Turbofans provide sufficient thrust at take-off (very low forward speed) as well as much higher cruise speeds.
I'm trying unsuccessfully to understand the physics of this or more specifically: If the pitch of the turbofan is set optimally for cruise, why does it not stall at take-off due to a very high angle of attack? Conversely, if the pitch was set for high thrust at take-off (or some lower speed setting), shouldn't the angle of attack reduce as speed increases thereby limiting cruise speed attainable? | 2022/12/20 | [
"https://aviation.stackexchange.com/questions/96520",
"https://aviation.stackexchange.com",
"https://aviation.stackexchange.com/users/66799/"
] | [](https://i.stack.imgur.com/TYq0t.png)
A large part of this is provided by the turbofan inlet design. Above pic is from Aircraft Gas Turbines by C.J.Houtman and was used earlier in [this answer](https://aviation.stackexchange.com/a/73029/21091): the inlet shape slows the incoming air down at cruise speed, and trades velocity in for pressure.
The variables:
* At TakeOff thrust needs to be maximal, the fan blades need to suck all the air in, and the fan does so at maximum RPM.
* At cruise thrust is lower, the RPM is lower, and the air inflow is slowed down.
Indeed the variation in thrust requirements and airspeed create quite a difficult set of operational circumstances to tune, care must be taken to prevent stalling of the blade tips, and stalling of the inflowing air-stream around the inlet nose at lower velocities, which is why the inlet is optimised for these lower airspeeds.
Propellers operate at lower airspeeds than turbofans, and operate at constant RPM with variable blade AoA for optimal thrust efficiency. Turbofans would also benefit from variable blade AoA, and efforts have been made to develop them, but the cost/gain ratio seems to be prohibitive for now. | One solution I haven’t seen addressed in the existing answers is compressor bleed valves. The speed with which the air passes over the compressor blades is a function of the pressure differences ahead of, and behind, the blades. The whole point of multi-stage compressors is for the pressure inside the engine to keep increasing as the air flows from inlet to combustion chamber.
At low airspeeds, and increasing pressures as the engine RPM increases, this means pressure is building up behind the blades faster than the plane is accelerating to create increased inlet pressure. This is what typically causes compressor stall… pressure increasing behind the blade reduces the speed of the flow over the blades.
Multi-stage engines will often have a bleed valve in the rear compressor stages that opens to let some air escape until airspeed increases. This alleviates the pressure building up behind the compressor blades, allowing faster flow, reducing blade AOA, alleviating stall.
Thus the fixed blade angle can be optimized for cruise performance and the engine manages effective AOA by managing pressure gradients inside the compressor. The bleed valves are pneumatic and operate autonomously with no crew intervention. |
206,638 | I am trying to recreate the garage door wall switch (making a custom assembly that has two buttons to toggle the door and toggle the light). The first thing that I am attempting to understand is the voltage being passed from the motor, to the wall switch and then back to the motor.
While looking at different articles and other places on the internet I discovered that the COM port on the motor passed power down to the wall controller and when the door button was pressed closed the circuit for a brief amount of time to make the motor move the door. To control the light, I thought that the same voltage was passed down through the same wire but instead a lower voltage was passed back up (making the switch more of a voltage divider). There is only one wire going back into the motor meaning it has to be something of a varying voltage to control the door and light.
When using a Fluke Multimeter I was getting a jumping reading from the wire connected to the COM port on the back of the wall control around 0.750 VAC. (I didn't like that it wasn't giving me a constant reading, originally I thought the meter was broke but put it into a standard outlet and got a solid 120 volts). When pressing the door control the voltage on the wire that went back up to the motor read 0.750 VAC. I figured that jumping the circuit would toggle the door, which it did. This made me think that the door opening was a simple instance of closing the circuit for about half a second but made me unsure of what the true voltage was.
The second challenge was how to tell the motor to turn the light on/off through that same wire. A few articles I read stated that the wall control acted as a voltage divider but not by how much or if the motor needed said amount of voltage for how long. When measuring with the light switch pressed down I got readings jumping around 0.350 VAC, but once again nothing concrete.
Here are my questions from all of this, and I am mainly asking those who have tried something like this before or know the common circuitry of these products.
1. How many volts are sent through the COM port on the motor to the wall controller?
2. How many volts are returned to the motor from the controller to open the door?
3. How many volts are returned to the motor from the controller to toggle the light?
I have a **Genie Pro Max** system, but from what I can tell and the fact that manufactures sell universal door switches I think most systems operate around the same circuitry.
Thank you in advance for your help. | 2020/10/16 | [
"https://diy.stackexchange.com/questions/206638",
"https://diy.stackexchange.com",
"https://diy.stackexchange.com/users/124498/"
] | Methinks you are tilting at windmills here.
Modern garage door openers are tiny computers with a set series of programmed responses, not dumb robots with simple voltage controls. If you want an overhead light controlled by a wall switch, you'll get much better results installing an overhead light and a wall switch for it than trying to hack your garage door opener into turning on its light without opening or closing the garage door.
Among other reasons, if you do manage to hack your opener and it then goes on to malfunction and hurt/kill someone, (as they still do from time to time, which is one reason that they have become so highly computerized) the manufacturer will be off the hook and you will be on the hook for responsibility because you have modified the opener. | Not a good answer. Listen to the other posters. It is likely a resistor placed in line with the light button. My Genie has three buttons. One for the door motor, one for the light and a push and hold button to lock the door. I suspect that the 'microprocessor' in the main unit is looking for one of three signals. A momentary dead short (motor control), a long dead short (lock control) and a momentary resistance, 10K ohms for instance (light control). Also, the programmed functions of the microprocessor also monitor your garage door block sensors to provide crush protection, so as long as you aren't trying to modify the block sensor operation, there should be no issue with anyone getting hurt...or killed. :) |
206,638 | I am trying to recreate the garage door wall switch (making a custom assembly that has two buttons to toggle the door and toggle the light). The first thing that I am attempting to understand is the voltage being passed from the motor, to the wall switch and then back to the motor.
While looking at different articles and other places on the internet I discovered that the COM port on the motor passed power down to the wall controller and when the door button was pressed closed the circuit for a brief amount of time to make the motor move the door. To control the light, I thought that the same voltage was passed down through the same wire but instead a lower voltage was passed back up (making the switch more of a voltage divider). There is only one wire going back into the motor meaning it has to be something of a varying voltage to control the door and light.
When using a Fluke Multimeter I was getting a jumping reading from the wire connected to the COM port on the back of the wall control around 0.750 VAC. (I didn't like that it wasn't giving me a constant reading, originally I thought the meter was broke but put it into a standard outlet and got a solid 120 volts). When pressing the door control the voltage on the wire that went back up to the motor read 0.750 VAC. I figured that jumping the circuit would toggle the door, which it did. This made me think that the door opening was a simple instance of closing the circuit for about half a second but made me unsure of what the true voltage was.
The second challenge was how to tell the motor to turn the light on/off through that same wire. A few articles I read stated that the wall control acted as a voltage divider but not by how much or if the motor needed said amount of voltage for how long. When measuring with the light switch pressed down I got readings jumping around 0.350 VAC, but once again nothing concrete.
Here are my questions from all of this, and I am mainly asking those who have tried something like this before or know the common circuitry of these products.
1. How many volts are sent through the COM port on the motor to the wall controller?
2. How many volts are returned to the motor from the controller to open the door?
3. How many volts are returned to the motor from the controller to toggle the light?
I have a **Genie Pro Max** system, but from what I can tell and the fact that manufactures sell universal door switches I think most systems operate around the same circuitry.
Thank you in advance for your help. | 2020/10/16 | [
"https://diy.stackexchange.com/questions/206638",
"https://diy.stackexchange.com",
"https://diy.stackexchange.com/users/124498/"
] | I haven't played with a Genie unit, but I spent some time with an oscilloscope and a Chamberlain/Lift Master unit several years ago. I found it has two modes of operation. One is the simple contact closure -- just short the two wires together and the motor will operate. The other mode is digital. The two wires carry power to the wall control, but they also carry a serial data communication protocol between the motor and the control. The only way to control the advanced features, such as turning the light on and off, is to use one of the wall controls with the digital interface.
As I recall, I also found that the two modes can't be used together. For example, you can't put the fancy wall control in one place in the garage and put a simple doorbell type switch in another place. When the simple switch shorts the wires the door operator goes into "dumb switch" mode and the fancy wall control ceases working (until the door operator is power cycled).
I couldn't say for sure whether your Genie works the same as that Chamberlain did, but I would not be surprised if it does. In any case, you wouldn't get far with discovering this nor reverse-engineering it armed with only a volt meter, unfortunately. | Not a good answer. Listen to the other posters. It is likely a resistor placed in line with the light button. My Genie has three buttons. One for the door motor, one for the light and a push and hold button to lock the door. I suspect that the 'microprocessor' in the main unit is looking for one of three signals. A momentary dead short (motor control), a long dead short (lock control) and a momentary resistance, 10K ohms for instance (light control). Also, the programmed functions of the microprocessor also monitor your garage door block sensors to provide crush protection, so as long as you aren't trying to modify the block sensor operation, there should be no issue with anyone getting hurt...or killed. :) |
206,638 | I am trying to recreate the garage door wall switch (making a custom assembly that has two buttons to toggle the door and toggle the light). The first thing that I am attempting to understand is the voltage being passed from the motor, to the wall switch and then back to the motor.
While looking at different articles and other places on the internet I discovered that the COM port on the motor passed power down to the wall controller and when the door button was pressed closed the circuit for a brief amount of time to make the motor move the door. To control the light, I thought that the same voltage was passed down through the same wire but instead a lower voltage was passed back up (making the switch more of a voltage divider). There is only one wire going back into the motor meaning it has to be something of a varying voltage to control the door and light.
When using a Fluke Multimeter I was getting a jumping reading from the wire connected to the COM port on the back of the wall control around 0.750 VAC. (I didn't like that it wasn't giving me a constant reading, originally I thought the meter was broke but put it into a standard outlet and got a solid 120 volts). When pressing the door control the voltage on the wire that went back up to the motor read 0.750 VAC. I figured that jumping the circuit would toggle the door, which it did. This made me think that the door opening was a simple instance of closing the circuit for about half a second but made me unsure of what the true voltage was.
The second challenge was how to tell the motor to turn the light on/off through that same wire. A few articles I read stated that the wall control acted as a voltage divider but not by how much or if the motor needed said amount of voltage for how long. When measuring with the light switch pressed down I got readings jumping around 0.350 VAC, but once again nothing concrete.
Here are my questions from all of this, and I am mainly asking those who have tried something like this before or know the common circuitry of these products.
1. How many volts are sent through the COM port on the motor to the wall controller?
2. How many volts are returned to the motor from the controller to open the door?
3. How many volts are returned to the motor from the controller to toggle the light?
I have a **Genie Pro Max** system, but from what I can tell and the fact that manufactures sell universal door switches I think most systems operate around the same circuitry.
Thank you in advance for your help. | 2020/10/16 | [
"https://diy.stackexchange.com/questions/206638",
"https://diy.stackexchange.com",
"https://diy.stackexchange.com/users/124498/"
] | Open/Close is a BUTTON that shorts the two wires - 0 Ohms.
Light On/Off is a BUTTON that connects the two wires through a 200 Ohm resistor.
Lock-out is a SWITCH that connects the two wires through an 82.5 Ohm resistor.
The only other component on the board is the LED which uses one of the resistors as a current limiter. | Not a good answer. Listen to the other posters. It is likely a resistor placed in line with the light button. My Genie has three buttons. One for the door motor, one for the light and a push and hold button to lock the door. I suspect that the 'microprocessor' in the main unit is looking for one of three signals. A momentary dead short (motor control), a long dead short (lock control) and a momentary resistance, 10K ohms for instance (light control). Also, the programmed functions of the microprocessor also monitor your garage door block sensors to provide crush protection, so as long as you aren't trying to modify the block sensor operation, there should be no issue with anyone getting hurt...or killed. :) |
206,638 | I am trying to recreate the garage door wall switch (making a custom assembly that has two buttons to toggle the door and toggle the light). The first thing that I am attempting to understand is the voltage being passed from the motor, to the wall switch and then back to the motor.
While looking at different articles and other places on the internet I discovered that the COM port on the motor passed power down to the wall controller and when the door button was pressed closed the circuit for a brief amount of time to make the motor move the door. To control the light, I thought that the same voltage was passed down through the same wire but instead a lower voltage was passed back up (making the switch more of a voltage divider). There is only one wire going back into the motor meaning it has to be something of a varying voltage to control the door and light.
When using a Fluke Multimeter I was getting a jumping reading from the wire connected to the COM port on the back of the wall control around 0.750 VAC. (I didn't like that it wasn't giving me a constant reading, originally I thought the meter was broke but put it into a standard outlet and got a solid 120 volts). When pressing the door control the voltage on the wire that went back up to the motor read 0.750 VAC. I figured that jumping the circuit would toggle the door, which it did. This made me think that the door opening was a simple instance of closing the circuit for about half a second but made me unsure of what the true voltage was.
The second challenge was how to tell the motor to turn the light on/off through that same wire. A few articles I read stated that the wall control acted as a voltage divider but not by how much or if the motor needed said amount of voltage for how long. When measuring with the light switch pressed down I got readings jumping around 0.350 VAC, but once again nothing concrete.
Here are my questions from all of this, and I am mainly asking those who have tried something like this before or know the common circuitry of these products.
1. How many volts are sent through the COM port on the motor to the wall controller?
2. How many volts are returned to the motor from the controller to open the door?
3. How many volts are returned to the motor from the controller to toggle the light?
I have a **Genie Pro Max** system, but from what I can tell and the fact that manufactures sell universal door switches I think most systems operate around the same circuitry.
Thank you in advance for your help. | 2020/10/16 | [
"https://diy.stackexchange.com/questions/206638",
"https://diy.stackexchange.com",
"https://diy.stackexchange.com/users/124498/"
] | I opened the wall control on my older non digital chamberlain/liftmaster (orange/red program button) to see how they do it.
There is only a single 1k ohm resistor on the board in series with the led and it is used for current limiting to the led.
The door control button is a dead short across the two wires. The LED on the keypad goes out and the voltage drops to zero.
For the light and lock push buttons they use two capacitors. A 1uf for the light and a 22uf cap for the lock/vacation button.
When the switch for light or lock function is pushed it does not short the wires but puts one or the other capacitor across the two wires.
There is no circuit to discharge the cap when you release those buttons so I would assume that the cap forms an oscillator circuit and the door opener determines which function is selected from the different oscillator frequencies for each button.
-A dead short is open/close door.
-A high frequency oscillation signal (1uf cap across wires) is identified as the light push.
-A low frequency oscillation signal (22uf cap across wires) is the lock/vacation button push.
I did not put a scope across the wires to confirm but that also answers why the original posters fluke meter does not provide a steady reading. Hope that helps. | Not a good answer. Listen to the other posters. It is likely a resistor placed in line with the light button. My Genie has three buttons. One for the door motor, one for the light and a push and hold button to lock the door. I suspect that the 'microprocessor' in the main unit is looking for one of three signals. A momentary dead short (motor control), a long dead short (lock control) and a momentary resistance, 10K ohms for instance (light control). Also, the programmed functions of the microprocessor also monitor your garage door block sensors to provide crush protection, so as long as you aren't trying to modify the block sensor operation, there should be no issue with anyone getting hurt...or killed. :) |
531,243 | I am trying to find this information online for a while but I cannot find any precise info, thus Q on this community seems appropriate.
I would like to know if a [device](https://www.xtorm.eu/en/power-banks/xtorm-60w-power-bank-voyager-26-000/) having USB PD charging port (capable to charge with 60W) will be able to use USB QC3.0 charging speed capabilities well?
Maybe it is manufacture specific matter and I should not expect to be any rule here? Then I just need to write to manufacturer and ask it is in cas of that specific device.
Thank you | 2020/11/08 | [
"https://electronics.stackexchange.com/questions/531243",
"https://electronics.stackexchange.com",
"https://electronics.stackexchange.com/users/268132/"
] | Assuming the lights are identical within a small tolerance, one has a very slightly higher resistance than the others.
With the same current in each, (as must be true in a series circuit) the higher resistance one will dissipate more power and heat up more : this further increases its resistance, heating it up further, increasing its resistance. Finally it may have twice or more the resistance of the other relatively cool bulbs, dissipating twice the power and glowing much brighter.
Measure the resistance of each bulb when cold.
Measure the voltage across each bulb when hot.
Compare the ratio of these voltages to the ratio of resistances when cold. | Assuming that the lights are identical, they should all be equally bright. Because the resistances are the same, the voltage is divided equally between them, each getting 1/3 of the battery voltage.
If they are not the same brightness, then they cannot be identical. Either one is somehow more efficient than the others, or one is higher wattage (lower resistance). |
182,868 | In Crawl, players are given blood to spend at the blacksmith. How exactly do you gain blood? If it's from combat, how much do you get and how is it determined? Per kill? Per hit? Can both the monsters and the human players get it? | 2014/09/02 | [
"https://gaming.stackexchange.com/questions/182868",
"https://gaming.stackexchange.com",
"https://gaming.stackexchange.com/users/9885/"
] | Blood is awarded for every encounter (room where enemies spawn) to each evil spirit player based on how much damage they did to the current hero. I don't have any definitive data, but from what I've observed I'm pretty confident that it is not based on your level. However, as you get more vitae, you will obviously deal more damage to the hero with better monsters, so it indirectly scales with your level. You can also get blood just for dealing minor damage to a hero with traps while he runs through a room.
In case you did not know, vitae is awarded based on how much experience the hero(s) gained during the dungeon level. So, it makes it very hard for a hero to win if the hero's body keeps changing hands often, because everyone else's monsters get much more powerful while hero experience gained is spread amongst all the players. If you plan on winning as the hero, take my advice: **don't die.** If you see the hero changing hands a lot, it might be best to bank on good ol' Kourok. | I believe it's per hit on the human, and it either scales with player level, dungeon level, or damage dealt. I have gotten blood as the human, both in blood fountain rooms, and the rooms that have a statue but no glyphs. I'm still trying to figure it out for sure, but I hope this helps! |
300,939 | Why can't the Klein-Gordon equation with a Couloumb potential describe the hydrogen atom?
Why can the first order Dirac equation explain it?
What are the failures? | 2016/12/25 | [
"https://physics.stackexchange.com/questions/300939",
"https://physics.stackexchange.com",
"https://physics.stackexchange.com/users/4435/"
] | Electrons are spin-1/2 particles (this qualifies them as fermions, but is not immediately relevant for this discussion).
KG equation is for spin-0 particles, whereas Dirac equation is for spin-1/2 particles. Therefore the proper equation to describe an electron is the latter.
Note that, however, the low-energy limit of both of them gives back Schrödinger equation, therefore in this approximation you can put the spin "by hand" and long as you need it, and this works both for fermions and for bosons. | The application of the Klein-Gordon equation for the hydrogen atom leads to logical contradictions.
Allowance for relativism in the Klein-Gordon equation should lead to more accurate solutions for the hydrogen atom compared with the Schrodinger equation. However, on the contrary, solutions became increasingly worse with an increase in the nuclear charge. Finally, for the element Z = 69 the solution of the Klein-Gordon equation terminates.
The Klein-Gordon equation has other drawbacks. Therefore, we can say that the Klein-Gordon equation is erroneous. |
300,939 | Why can't the Klein-Gordon equation with a Couloumb potential describe the hydrogen atom?
Why can the first order Dirac equation explain it?
What are the failures? | 2016/12/25 | [
"https://physics.stackexchange.com/questions/300939",
"https://physics.stackexchange.com",
"https://physics.stackexchange.com/users/4435/"
] | Electrons are spin-1/2 particles (this qualifies them as fermions, but is not immediately relevant for this discussion).
KG equation is for spin-0 particles, whereas Dirac equation is for spin-1/2 particles. Therefore the proper equation to describe an electron is the latter.
Note that, however, the low-energy limit of both of them gives back Schrödinger equation, therefore in this approximation you can put the spin "by hand" and long as you need it, and this works both for fermions and for bosons. | The reason is electron spin. The energy of the Dirac and Klein-Gordon solution differ precisely by the substitution l<->j.
The Klein-Gordon equation needs to be extended with a term describing the interaction of electron spin with the nuclear potential. The resulting equation is known as the squared Dirac equation. See Itzykson and Zuber, Ch. 2.3, for a solution of the Dirac equation for the single electron case *via* the squared Dirac equation. |
300,939 | Why can't the Klein-Gordon equation with a Couloumb potential describe the hydrogen atom?
Why can the first order Dirac equation explain it?
What are the failures? | 2016/12/25 | [
"https://physics.stackexchange.com/questions/300939",
"https://physics.stackexchange.com",
"https://physics.stackexchange.com/users/4435/"
] | The reason is electron spin. The energy of the Dirac and Klein-Gordon solution differ precisely by the substitution l<->j.
The Klein-Gordon equation needs to be extended with a term describing the interaction of electron spin with the nuclear potential. The resulting equation is known as the squared Dirac equation. See Itzykson and Zuber, Ch. 2.3, for a solution of the Dirac equation for the single electron case *via* the squared Dirac equation. | The application of the Klein-Gordon equation for the hydrogen atom leads to logical contradictions.
Allowance for relativism in the Klein-Gordon equation should lead to more accurate solutions for the hydrogen atom compared with the Schrodinger equation. However, on the contrary, solutions became increasingly worse with an increase in the nuclear charge. Finally, for the element Z = 69 the solution of the Klein-Gordon equation terminates.
The Klein-Gordon equation has other drawbacks. Therefore, we can say that the Klein-Gordon equation is erroneous. |
1,117,706 | I have a brand new computer with an SSD and an HDD both plugged in with SATA. Windows is installed on the SSD (C:) and the HDD (E:) is practically empty.
I want the default windows libraries (i.e Downloads, Documents, Pictures etc.) to all be located on the HDD in order to save space on the SSD. I moved the downloads folder there using the properties menu (in the Location tab), but I guess I entered the Documents Folder location wrong and now it thinks the whole disk is that folder, and I can't restore it to default - I get an "invalid path" error.
Also, I tried right-clicking the Libraries folder and then restore to default with no help.
What it looks like:
Will formatting the HDD help? Any other advice? | 2016/08/25 | [
"https://superuser.com/questions/1117706",
"https://superuser.com",
"https://superuser.com/users/598935/"
] | Formatting should help, otherwise, try a system restore. Make sure you define an actual folder next time. Video: <https://www.youtube.com/watch?v=QG4LXw4Nd5U> | You might be able to use System Restore to roll the system back to solve this problem, if there is a restore point of course. |
214,076 | How many RAID "Channels" are on the PERC H700? 2? How would I verify which RAID is on which channel, and can I move them from one channel to another to balance the load per channel better? | 2010/12/18 | [
"https://serverfault.com/questions/214076",
"https://serverfault.com",
"https://serverfault.com/users/62919/"
] | [From what we know of your environment](https://serverfault.com/questions/213904/whats-the-right-raid-controller-for-my-dell-server) you don't have enough disk-drives to worry about load-balancing. As Chris S said, SAS is different than SCSI in which there is one connection (channel in old school SCSI lingo) per drive. You have 6 drives, and a total of 8 connections to connect them to. You're already getting the maximum parallelism you're going to get out of the system.
---
Where this kind of thing *can* come into effect is if you're using SAS Expanders. The H700 can connect to up to 8 of those expanders (probably). Those expanders in turn can contain up to 25 drives in them. If you were pushing this card to the limit like that, you'd want to make sure your RAID volumes were striped across the enclosures (example: disks 1-5 in each enclosure are in a single RAID set for a total RAID of 40 drives), as that would leverage the exact parallelism that using multiple SCSI channels did in the pre-SAS days. | I think you're stuck in old SCSI terminology. The PERC H700 uses SAS connections, which is one connection per drive; there are no channels like there were in SCSI.
The H700 Card has a single connector which fans out to 4 SAS drives. The H700 Onboard Chip has two 4x connections as aforementioned. I don't know if the card supports SAS Expanders. |
677 | For my undergraduate research I'm looking for a database that gives the bound form of a particular protein structure. Is there any database that provide us with such data? So far I've found following proteins related to my work
* Ascorbate peroxidase (APX)
* Beta-glucosidase
* Calcineurin b-like protein-interacting protein kinase.
I've searched in PDB and UNIPROT. | 2017/06/13 | [
"https://bioinformatics.stackexchange.com/questions/677",
"https://bioinformatics.stackexchange.com",
"https://bioinformatics.stackexchange.com/users/833/"
] | Tried looking for an explicit database? i.e.
* ComSin: database of protein structures in bound (complex) and unbound (single) states in relation to their intrinsic disorder: <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2808974/> or
* LigASite: a database of biologically relevant binding sites in proteins with known apo-structures <https://www.ncbi.nlm.nih.gov/pubmed/17933762>
Else the PDB itself has a very powerful advanced search that should allow you to do this: <http://www.rcsb.org/pdb/search/advSearch.do> | Are you aware of [BRENDA](http://www.brenda-enzymes.org/index.php)? I was just introduced to it today for a completely separate reason (looking at carbohydrate enzyme families in the *Nippostrongylus brasiliensis* proteome), and it seems to be a fairly comprehensive database. There is at least a literature link there for the [ascorbate-complexed crystalisation of Ascorbate peroxidase](http://www.brenda-enzymes.org/enzyme.php?ecno=1.11.1.11#Crystallization/COMMENTARY) on that site. Following through the paper, I see that [the complex has been uploaded to PDB](http://www.rcsb.org/pdb/explore/explore.do?pdbId=1OAF). |
50,474,687 | I am reading a book regarding tomcat 7. In a section that shortly explains the architecture of the container he says: "Only one tomcat instance can live in a single Java Virtual Machine(JVM)..." later, the author states: "You can still run multiple instances on same physical box, but as separated Java processes..." What is actually the meaning of running the Tomcat inside of the same physical box, but in a different process? | 2018/05/22 | [
"https://Stackoverflow.com/questions/50474687",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/3619911/"
] | The physical box is a single computer box. The single computer can have more than one [operating system process](https://en.wikipedia.org/wiki/Process_(computing)) that both run Tomcat. This similar to the way you can have more than one Notepad application open at the same time. Both are open at the same time, and you can interact with either instance. The operating system handles context switching so the same physical box hardware supports more than one process. | Tomcat is basically a Java process like any other. You can run multiple jvm instances on an operating system. If you wish to run a java application twice (like tomcat for example) you can simply do so.
Note that there may be issues of port/addresses collision to consider... |
256,841 | I have XEN Server installed and running several VM's on a newer dell server with hardware raid. My concern is what happens if one of the drives fails? Can XEN server be configured to receive that error and alert someone? | 2011/04/07 | [
"https://serverfault.com/questions/256841",
"https://serverfault.com",
"https://serverfault.com/users/41580/"
] | Since this is a Dell server, you should install OMSA managed node on it, and use that to send email and SNMP alerts about hardware issues.
Another option is to use the alerts in the DRAC, but those don't cover storage issues iirc. | You may want to consider installing the [Dell Edition](http://www.delltechcenter.com/page/Citrix+XenServer+Dell+Edition) of Xen Server - this comes with all the Dell OpenManage stuff built in, and can almost certainly do what you're asking. |
256,841 | I have XEN Server installed and running several VM's on a newer dell server with hardware raid. My concern is what happens if one of the drives fails? Can XEN server be configured to receive that error and alert someone? | 2011/04/07 | [
"https://serverfault.com/questions/256841",
"https://serverfault.com",
"https://serverfault.com/users/41580/"
] | Since this is a Dell server, you should install OMSA managed node on it, and use that to send email and SNMP alerts about hardware issues.
Another option is to use the alerts in the DRAC, but those don't cover storage issues iirc. | OMSA also gives you the possibility to run executables (e.g. shell-scripts) on warning or critical-type storage events.
In that script you can check whether your array is degraded (using omreport storage ...).
If that`s the case you can start further things (e.g. live-migrate to another XEN-server).
Once OMSA is installed smartd will possibly also capture harddisk-events (I did not verify this deeply).
I for myself trigger a mail to root using OMSA so a human can take action (call support and get a replacement disk) before the next disk fails, for example.
If you've got a DRAC-Card other than DRAC4 (older or newer) the DRAC itself won't alert upon hard disk failures, OMSA will however. |
256,841 | I have XEN Server installed and running several VM's on a newer dell server with hardware raid. My concern is what happens if one of the drives fails? Can XEN server be configured to receive that error and alert someone? | 2011/04/07 | [
"https://serverfault.com/questions/256841",
"https://serverfault.com",
"https://serverfault.com/users/41580/"
] | OMSA also gives you the possibility to run executables (e.g. shell-scripts) on warning or critical-type storage events.
In that script you can check whether your array is degraded (using omreport storage ...).
If that`s the case you can start further things (e.g. live-migrate to another XEN-server).
Once OMSA is installed smartd will possibly also capture harddisk-events (I did not verify this deeply).
I for myself trigger a mail to root using OMSA so a human can take action (call support and get a replacement disk) before the next disk fails, for example.
If you've got a DRAC-Card other than DRAC4 (older or newer) the DRAC itself won't alert upon hard disk failures, OMSA will however. | You may want to consider installing the [Dell Edition](http://www.delltechcenter.com/page/Citrix+XenServer+Dell+Edition) of Xen Server - this comes with all the Dell OpenManage stuff built in, and can almost certainly do what you're asking. |
98,308 | A person was handling a small plastic can filled with small beads. His hand fumbled and all the beads popped burst and spread all over the floor.
What are correct verbs describe this movement?
>
> 1. The beads popped burst all over the floor.
> 2. He popped burst the beads and they are now all over the floor.
> 3. The beads splashed(?)
>
>
> | 2016/08/02 | [
"https://ell.stackexchange.com/questions/98308",
"https://ell.stackexchange.com",
"https://ell.stackexchange.com/users/16246/"
] | If the can (with no top) was tilted and the beads fell out, that is not "bursting".
*bursting* would be (for example) when a sealed container with some contents builds up pressure inside the container, so that it would break open.
I would say:
>
> The beads **spilled** all over the floor.
>
>
>
[*spill*](https://ahdictionary.com/word/search.html?q=spill):
>
> 1. To cause or allow (a substance) to run or fall out of a container.
> 2. To scatter (objects) from containment: *spilled the armload of books on the desk*.
>
>
> | It would just be "The beads burst all over the floor." Popped burst is just two verbs in front of each other, and is neither necessary nor (as far as I know) grammatically correct. |
69,886 | >
> The man stuttered too, perhaps when (he was) confused.
>
>
>
Can I omit "he was" in this sentence? Why or why not? | 2015/10/04 | [
"https://ell.stackexchange.com/questions/69886",
"https://ell.stackexchange.com",
"https://ell.stackexchange.com/users/1806/"
] | The sentence (A) isn't correct grammatically.
"I couldn't open the door" is in the past. As a matter of fact, you are locked in and unable to open the door at the present time. So the correct sentence should be:
I am locked in here and cannot open the door. Can you help me?
The second sentence (B), which is in the past, is correct grammatically. Could is the past of can. | usually could can be used for wishing in a sentence like "I could have a pet"
we can say the second sentence is correct but the first one is not pretty okay!
for present(if we just want to use can as its own meaning) we can use Can |
31,999 | Of all the ways I could come up with to pronounce the word "busy", "bizzy" would be very low on my list. At least "bussy" or "boosy". Why "bizzy"? | 2011/06/29 | [
"https://english.stackexchange.com/questions/31999",
"https://english.stackexchange.com",
"https://english.stackexchange.com/users/10041/"
] | The problem isn't so much that "busy" is pronounced "bizzy", but that "bizzy" is still spelled "busy". An awful lot of English spelling is based on a language that would sound very foreign to most English speakers today -- English as it was before the [Great Vowel Shift](http://en.wikipedia.org/wiki/Great_Vowel_Shift) (and at a point when we still had velar fricatives, which is why there are words spelled with "gh"). The language has undergone major changes in pronunciation, while the spelling has merely been tidied up a bit so that words are spelled the same way every time. (Mostly.)
If you really think about it, almost none of English spelling makes any sense with regard to vowels. It used to, at least to the same extent that alphabetic writing makes sense in any language. Your example "bussy" would have been pronounced roughly like the Modern English word "boozey", but with a doubled/stressed "s"; "boosy" would have had a long "o" (both in the modern schoolroom sense that "the vowel says its name", and in the sense of duration).
What happened during the Great Vowel Shift was systematic. That's why we're able to derive spelling rules dealing with things like "silent Es" and so forth -- the "real" orthography applies to a differently-pronounced language that has changed in a particular way, so if we know how it has changed, we know how to apply the rules of the old language to the new one. But there are also differences that are dialectical -- the accepted spelling of some words reflects a dialect of Middle or Early Modern English that may have won the war, but it lost some of the battles. If "busy" is spelled "busy" today, it's probably because it was pronounced that way in the London dialect at one time. Unfortunately, written documents are the only recordings we have of the pronunciation, so we can never know exactly how it was pronounced, but we *do* know that there was at least *some* method to the madness back then.
As Ham and Bacon points out, "busy" is an old word. The problem with giving Old English roots (in this case, "bisig"), though, is that Old English was itself a bundle of dialects. Generally, what's reflected in etymologies is a "majority rules" case. That does not imply that the Old English dialect that gave rise to the Middle English dialect that made "busy" (or "busie") seem like a good idea did not also use a "u" or "y" (high front rounded) sound in their version of the word. | I reckon its in its etymology. It originally came from the Dutch word [`bezig`:](http://www.etymonline.com/index.php?search=busy&searchmode=none)
>
> O.E. bisig "careful, anxious, busy, occupied," cognate with O.Du. bezich,
>
>
>
The root was actually spelt with a 'z', and it was changed to 's' later. This can also be seen in the word ["organisation":](http://dictionary.reference.com/browse/organisation)
>
> 1375–1425; late Middle English organizacion < Medieval Latin organizātiōn
>
>
>
Note that its root, Latin, was spelt with a 'z'. |
31,999 | Of all the ways I could come up with to pronounce the word "busy", "bizzy" would be very low on my list. At least "bussy" or "boosy". Why "bizzy"? | 2011/06/29 | [
"https://english.stackexchange.com/questions/31999",
"https://english.stackexchange.com",
"https://english.stackexchange.com/users/10041/"
] | The spelling of *busy* (and *bury*) is the result of dialect mixture. Different Middle English varieties had different outcomes of Old English short /y/. In the East Midlands variety that underlies the standard, it became short /u/ as in *blush*; in Kent, short /ɛ/ as in *merry* (for people who pronounce it with the same vowel as in *met*, anyhow); in the West Midlands, short /i/ as in *bridge*: all three of these words had short /y/ in Old English (*blyscan, myrige, brycge*). *Busy* is an East Midlands spelling for an West Midlands pronunciation; *bury* is likewise a East Midlands spelling, but for a Kentish pronunciation.
**UPDATE**: I'm dyslexic about left and right, which also extends to east and west. Obviously it's East Midlands (where London is) that underlies the standard, so that's what this now says. | I reckon its in its etymology. It originally came from the Dutch word [`bezig`:](http://www.etymonline.com/index.php?search=busy&searchmode=none)
>
> O.E. bisig "careful, anxious, busy, occupied," cognate with O.Du. bezich,
>
>
>
The root was actually spelt with a 'z', and it was changed to 's' later. This can also be seen in the word ["organisation":](http://dictionary.reference.com/browse/organisation)
>
> 1375–1425; late Middle English organizacion < Medieval Latin organizātiōn
>
>
>
Note that its root, Latin, was spelt with a 'z'. |
31,999 | Of all the ways I could come up with to pronounce the word "busy", "bizzy" would be very low on my list. At least "bussy" or "boosy". Why "bizzy"? | 2011/06/29 | [
"https://english.stackexchange.com/questions/31999",
"https://english.stackexchange.com",
"https://english.stackexchange.com/users/10041/"
] | The problem isn't so much that "busy" is pronounced "bizzy", but that "bizzy" is still spelled "busy". An awful lot of English spelling is based on a language that would sound very foreign to most English speakers today -- English as it was before the [Great Vowel Shift](http://en.wikipedia.org/wiki/Great_Vowel_Shift) (and at a point when we still had velar fricatives, which is why there are words spelled with "gh"). The language has undergone major changes in pronunciation, while the spelling has merely been tidied up a bit so that words are spelled the same way every time. (Mostly.)
If you really think about it, almost none of English spelling makes any sense with regard to vowels. It used to, at least to the same extent that alphabetic writing makes sense in any language. Your example "bussy" would have been pronounced roughly like the Modern English word "boozey", but with a doubled/stressed "s"; "boosy" would have had a long "o" (both in the modern schoolroom sense that "the vowel says its name", and in the sense of duration).
What happened during the Great Vowel Shift was systematic. That's why we're able to derive spelling rules dealing with things like "silent Es" and so forth -- the "real" orthography applies to a differently-pronounced language that has changed in a particular way, so if we know how it has changed, we know how to apply the rules of the old language to the new one. But there are also differences that are dialectical -- the accepted spelling of some words reflects a dialect of Middle or Early Modern English that may have won the war, but it lost some of the battles. If "busy" is spelled "busy" today, it's probably because it was pronounced that way in the London dialect at one time. Unfortunately, written documents are the only recordings we have of the pronunciation, so we can never know exactly how it was pronounced, but we *do* know that there was at least *some* method to the madness back then.
As Ham and Bacon points out, "busy" is an old word. The problem with giving Old English roots (in this case, "bisig"), though, is that Old English was itself a bundle of dialects. Generally, what's reflected in etymologies is a "majority rules" case. That does not imply that the Old English dialect that gave rise to the Middle English dialect that made "busy" (or "busie") seem like a good idea did not also use a "u" or "y" (high front rounded) sound in their version of the word. | The spelling of *busy* (and *bury*) is the result of dialect mixture. Different Middle English varieties had different outcomes of Old English short /y/. In the East Midlands variety that underlies the standard, it became short /u/ as in *blush*; in Kent, short /ɛ/ as in *merry* (for people who pronounce it with the same vowel as in *met*, anyhow); in the West Midlands, short /i/ as in *bridge*: all three of these words had short /y/ in Old English (*blyscan, myrige, brycge*). *Busy* is an East Midlands spelling for an West Midlands pronunciation; *bury* is likewise a East Midlands spelling, but for a Kentish pronunciation.
**UPDATE**: I'm dyslexic about left and right, which also extends to east and west. Obviously it's East Midlands (where London is) that underlies the standard, so that's what this now says. |
25,167 | I am trying to research ways into obtaining landuse data for a project which calculates the visual impacts of wind parks.
I have a DEM and DOPs for a relatively large region (5000km²), but I have no landuse data.
Does anyone know how I could obtain or create such data to create a database of landuse types .i.e residential, agriculture, industry, forest, woodland etc?
Is is possible to create such a dataset from satelite imagery or would I have to think about digitizing polygons from aerial photos?
I would be very interested in hearing view or reading methodologies for similar projects. | 2012/05/10 | [
"https://gis.stackexchange.com/questions/25167",
"https://gis.stackexchange.com",
"https://gis.stackexchange.com/users/5636/"
] | Creating landuse database, you need sensor technologies to detect and classify objects. i think you already know that:
>
> There are two main types of remote sensing: passive remote sensing and
> active remote sensing. Passive sensors detect natural radiation that
> is emitted or reflected by the object or surrounding areas. Reflected
> sunlight is the most common source of radiation measured by passive
> sensors.
>
>
> Active collection, on the other hand, emits energy in order to scan
> objects and areas whereupon a sensor then detects and measures the
> radiation that is reflected or backscattered from the target. RADAR
> and LiDAR are examples of active remote sensing where the time delay
> between emission and return is measured, establishing the location,
> height, speed and direction of an object.
>
>
>
if you dont have multi-band aerial photo, it is very hard to classify objects and the classification accuracy rate will be down for certain objects.
there is lots of free data(old dated) on internet which can you use for classification. you can also find some free data [here](http://www.terrainmap.com/rm39.html).
in remote sensing world there are lots of satellite with different features for different needs. they diverses from others with lots of features as spatial, temporal and spectral resolutions. for spectral resoulutions:
The spatial resolution specifies the pixel size of satellite images covering the earth surface.
>
> High spatial resolution: 0.6 - 4 m
>
>
> » GeoEye-1
>
>
> » WorldView-2
>
>
> » WorldView-1
>
>
> » QuickBird
>
>
> » IKONOS
>
>
> » FORMOSAT-2
>
>
> » ALOS
>
>
> » CARTOSAT-1
>
>
> » SPOT-5 Medium spatial resolution: 4 - 30 m
>
>
> » ASTER
>
>
> » LANDSAT 7
>
>
> » CBERS-2 Low spatial resolution: 30 - > 1000 m
>
>
>
for temporal specification:
The temporal resolution specifies the revisiting frequency of a satellite sensor for a specific location.
>
> High temporal resolution: < 24 hours - 3 days
>
>
> Medium temporal resolution: 4 - 16 days
>
>
> Low temporal resolution: > 16 days
>
>
>
for spectral resolution :
Spectral Resolution
In the first instance, a sensor's spectral resolution specifies the number of spectral bands in which the sensor can collect reflected radiance. But the number of bands is not the only important aspect of spectral resolution. The position of bands in the electromagnetic spectrum is important, too.
>
> High spectral resolution: - 220 bands
>
>
> Medium spectral resolution: 3 - 15 bands
>
>
> Low spectral resolution: - 3 bands
>
>
>
you can find more information about Characterization of Satellite Remote Sensing Systems [here](http://www.satimagingcorp.com/characterization-of-satellite-remote-sensing-systems.html).
you can find more tutorial about classification with remote sensing data and Image Anlaysis in [envi site](http://www.google.com.tr/url?sa=t&rct=j&q=classification%20tutorial&source=web&cd=2&ved=0CGwQFjAB&url=http://www.exelisvis.com/portals/0/tutorials/envi/Classification_Methods.pdf&ei=OnmrT6S2Kqvb4QSmtZytCQ&usg=AFQjCNHMnhtm-vSjh5hMabdnGO02DGE7oA&cad=rja) (they give example data too). | If your study area is within the [conterminous](http://en.wikipedia.org/wiki/Contiguous_United_States) United States, you might be interested in the [National Land Cover Database (NLCD)](http://www.mrlc.gov/); the latest data is from 2006, and is at a 30-meter resolution. |
25,167 | I am trying to research ways into obtaining landuse data for a project which calculates the visual impacts of wind parks.
I have a DEM and DOPs for a relatively large region (5000km²), but I have no landuse data.
Does anyone know how I could obtain or create such data to create a database of landuse types .i.e residential, agriculture, industry, forest, woodland etc?
Is is possible to create such a dataset from satelite imagery or would I have to think about digitizing polygons from aerial photos?
I would be very interested in hearing view or reading methodologies for similar projects. | 2012/05/10 | [
"https://gis.stackexchange.com/questions/25167",
"https://gis.stackexchange.com",
"https://gis.stackexchange.com/users/5636/"
] | Creating landuse database, you need sensor technologies to detect and classify objects. i think you already know that:
>
> There are two main types of remote sensing: passive remote sensing and
> active remote sensing. Passive sensors detect natural radiation that
> is emitted or reflected by the object or surrounding areas. Reflected
> sunlight is the most common source of radiation measured by passive
> sensors.
>
>
> Active collection, on the other hand, emits energy in order to scan
> objects and areas whereupon a sensor then detects and measures the
> radiation that is reflected or backscattered from the target. RADAR
> and LiDAR are examples of active remote sensing where the time delay
> between emission and return is measured, establishing the location,
> height, speed and direction of an object.
>
>
>
if you dont have multi-band aerial photo, it is very hard to classify objects and the classification accuracy rate will be down for certain objects.
there is lots of free data(old dated) on internet which can you use for classification. you can also find some free data [here](http://www.terrainmap.com/rm39.html).
in remote sensing world there are lots of satellite with different features for different needs. they diverses from others with lots of features as spatial, temporal and spectral resolutions. for spectral resoulutions:
The spatial resolution specifies the pixel size of satellite images covering the earth surface.
>
> High spatial resolution: 0.6 - 4 m
>
>
> » GeoEye-1
>
>
> » WorldView-2
>
>
> » WorldView-1
>
>
> » QuickBird
>
>
> » IKONOS
>
>
> » FORMOSAT-2
>
>
> » ALOS
>
>
> » CARTOSAT-1
>
>
> » SPOT-5 Medium spatial resolution: 4 - 30 m
>
>
> » ASTER
>
>
> » LANDSAT 7
>
>
> » CBERS-2 Low spatial resolution: 30 - > 1000 m
>
>
>
for temporal specification:
The temporal resolution specifies the revisiting frequency of a satellite sensor for a specific location.
>
> High temporal resolution: < 24 hours - 3 days
>
>
> Medium temporal resolution: 4 - 16 days
>
>
> Low temporal resolution: > 16 days
>
>
>
for spectral resolution :
Spectral Resolution
In the first instance, a sensor's spectral resolution specifies the number of spectral bands in which the sensor can collect reflected radiance. But the number of bands is not the only important aspect of spectral resolution. The position of bands in the electromagnetic spectrum is important, too.
>
> High spectral resolution: - 220 bands
>
>
> Medium spectral resolution: 3 - 15 bands
>
>
> Low spectral resolution: - 3 bands
>
>
>
you can find more information about Characterization of Satellite Remote Sensing Systems [here](http://www.satimagingcorp.com/characterization-of-satellite-remote-sensing-systems.html).
you can find more tutorial about classification with remote sensing data and Image Anlaysis in [envi site](http://www.google.com.tr/url?sa=t&rct=j&q=classification%20tutorial&source=web&cd=2&ved=0CGwQFjAB&url=http://www.exelisvis.com/portals/0/tutorials/envi/Classification_Methods.pdf&ei=OnmrT6S2Kqvb4QSmtZytCQ&usg=AFQjCNHMnhtm-vSjh5hMabdnGO02DGE7oA&cad=rja) (they give example data too). | There are several global land cover products. Globcover, from ESA, is the one (I think) with the best resolution - 300m. It has a fairly detailed nomenclature based on FAO's classification system.
Also, if your AOI is in Europe, you can get CORINE Land Cover - a Land Use/Land Cover vector Map for Europe with 25ha of Minimum Mapping Unit and 44 classes of thematic detail.
Both are free.
I'm not sure at what scale and what region you're working in, but these are very good solutions. If you're getting into deriving your own Land Use/Land Cover map, you may as well forget the rest cause you'll have much work on your hands. |
148,647 | I have a CD that was started in a 'multi-session' format, about 10 years ago, using CD writing software that I no longer have, on hardware that is long gone. The disk has files on it that are otherwise unavailable, but my current setup doesn't understand the particular non-finalized format of the disk. Does anyone here know of any utilities that can read this sort of disk?
the gory details: the disk was written with something called 'adaptec', that came pre-installed on what was probably a windows 95 or possibly windows 98 packard-bell, definitely pre-DVD era. I'm currently at windows XP SP3, but if someone says windows 7 can do it natively, that'll be a good excuse to upgrade. | 2010/06/03 | [
"https://superuser.com/questions/148647",
"https://superuser.com",
"https://superuser.com/users/13130/"
] | [IsoBuster](http://www.isobuster.com/), [CDRoller](http://www.cdroller.com/), or [CD Recovery Toolbox Free](http://www.oemailrecovery.com/cd_recovery.html) might be able to read the data back off of that disc. CD Recovery Toolbox Free is, well, freeware, but not as powerful as the other two. IsoBuster has free functionality and Pro functionality that requires registration. If you burned the disc as an open multi-session disc with Easy CD Creator, then the free functionality should be all you need. If you burned the disc with DirectCD, then you'd need the Pro version.
Both Easy CD Creator and DirectCD were Adaptec products.
Finally, there's [Roxio's UDF Reader](http://www.roxio.com/enu/support/udf/software_updates.html) -- that may also allow you to read the disc. Roxio took over the development of Adaptec's CD/DVD burning software several years ago. | Problem I had was someone burned files on a CD and didn't finalize the CD to read on other systems.
Without using the CD on the original computer that burned it, I managed to do it with a program called "PowerISO" (not knowing what software or OS version that created the CD).
1. Insert the CD
2. Start PowerISO and tell it to open the CD
3. extract the data to a local folder (not another CD)
4. confirm the data, then burn it to another CD (if necessary)
This was done on a CD burned (& not finalized) dated 2/2/2016 |
148,647 | I have a CD that was started in a 'multi-session' format, about 10 years ago, using CD writing software that I no longer have, on hardware that is long gone. The disk has files on it that are otherwise unavailable, but my current setup doesn't understand the particular non-finalized format of the disk. Does anyone here know of any utilities that can read this sort of disk?
the gory details: the disk was written with something called 'adaptec', that came pre-installed on what was probably a windows 95 or possibly windows 98 packard-bell, definitely pre-DVD era. I'm currently at windows XP SP3, but if someone says windows 7 can do it natively, that'll be a good excuse to upgrade. | 2010/06/03 | [
"https://superuser.com/questions/148647",
"https://superuser.com",
"https://superuser.com/users/13130/"
] | [IsoBuster](http://www.isobuster.com/), [CDRoller](http://www.cdroller.com/), or [CD Recovery Toolbox Free](http://www.oemailrecovery.com/cd_recovery.html) might be able to read the data back off of that disc. CD Recovery Toolbox Free is, well, freeware, but not as powerful as the other two. IsoBuster has free functionality and Pro functionality that requires registration. If you burned the disc as an open multi-session disc with Easy CD Creator, then the free functionality should be all you need. If you burned the disc with DirectCD, then you'd need the Pro version.
Both Easy CD Creator and DirectCD were Adaptec products.
Finally, there's [Roxio's UDF Reader](http://www.roxio.com/enu/support/udf/software_updates.html) -- that may also allow you to read the disc. Roxio took over the development of Adaptec's CD/DVD burning software several years ago. | One alternative I found that does not require you to purchase paid software and resolves the problem:
1. <https://cdburnerxp.se/help/Intro/cdburnerxp>
This can read the CD and create an ISO image file that contains all sessions etc.
2. <https://www.altap.cz/salamander/downloads/>
This can open the ISO properly and will see all files from all sessions. You can copy the files from it to somewhere on your drive.
Both are freeware. |
407,866 | Recently I received this email from a client with reference to a purchase order:
>
> If you have received I will have to reinstate the lines on the po and then you need to grn.
>
>
>
I can't figure out what the meaning could be. | 2017/08/29 | [
"https://english.stackexchange.com/questions/407866",
"https://english.stackexchange.com",
"https://english.stackexchange.com/users/252044/"
] | GRN means [Goods Received Note](https://www.collinsdictionary.com/us/dictionary/english/goods-received-note) (sometimes called Goods Receipt Note). The goods receipt note is an internal document. This record is used to confirm all goods have been received and often compared to a purchase order before payment is issued.
The client wants you to *send* a GRN which will describe each item and the quantity of each item received.
The client can use it to raise any issues, update their stock records or use it to match against the original purchase order and supplier invoice. | Not sure about the phrase "grn" as a whole, but perhaps the "rn" portion stands for "reference number?" |
7,290 | The [no hair theorem](http://en.wikipedia.org/wiki/No-hair_theorem) says that a black hole can be characterized by a small number of parameters that are visible from distance - mass, angular momentum and electric charge.
For me it is puzzling why local quantities are not included, i.e. quantum numbers different from electrical charge. Lack of such parameters means breaking of the conservations laws (for a black hole made of baryons, Hawking radiation then is 50% baryonic and 50% anti-baryonic).
The question is:
* If lack of baryonic number as a black hole parameter is a well established relation?
OR
* It is (or may be) only an artifact of lack of unification between QFT and GR? | 2011/03/20 | [
"https://physics.stackexchange.com/questions/7290",
"https://physics.stackexchange.com",
"https://physics.stackexchange.com/users/184/"
] | The no hair theorem is proven in classical gravity, in asymptotically flat 4 dimensional spacetimes, and with particular matter content. When looking at more general circumstances, we are starting to see that variations of the original assumptions give the black hole more hair. For example, for asymptotically AdS one can have scalar hair (a fact which is used to build holographic superconductors). For five dimensional spaces black holes (and black rings) can have dipole moments of gauge charges. Maybe there are more surprises.
But, the basic intuition behind the no hair theorem is still valid. The basic fact used in all these constructions is that when the object falls into a black hole, it can imprint its existence on the black hole exterior only if it associated with a long ranged field. So for example an electron will change the charge of the black hole which means that black hole will have a Coulomb field. You'd be able to measure the total charge by an appropriate Gauss surface. Note that gravity has no conserved local currents (see [this discussion](https://physics.stackexchange.com/questions/7244/what-is-energy-in-string-theory/7263#7263)), the only thing you'd be able to measure is the *total* charge.
As for baryon number, it is not associated with long ranged force, when it falls into black hole there is nothing to remember that fact, and the baryon number is not conserved. This is just one of the reasons there is a general belief that global charges (those quantities which are not accompanied by long ranged forces) are not really conserved. For the Baryon number we know that for a fact: our world has more baryons than anti baryons, so the observed baryon number symmetry must only be approximate. It must have been violated in the early universe when all baryons were generated (look for a related discussion [here](https://physics.stackexchange.com/questions/6321/matter-antimatter-asymmetry-in-experiments/6323#6323)), a process which is referred to as baryogenesis. | One way out of this--if you believe that Hawking radiation is real, and that black holes completely evaporate, then:
1) the Hawking radiation violates the positive energy conditions. These are assumptions in the no-hair theorem. So, we don't expect the no-hair theorem to be valid for black holes if Hawking radiation is important.
2) If the evaporation profile evolves in a certain way, you can prevent the formation of a true event horizon, only having an [apparent horizon](http://blog.relativity.livingreviews.org/tag/apparent-horizons/) appear for a finite amount of time. This will enable the information about the input baryon number to escape the black hole.
But classically, you are right. It is well-established that you lose the information about what you put into the black hole--classically, a black hole formed from neutrino collapse is identical to a black hole formed from the collapse of a neutron star or photons or gravitational waves or whatever. |
118,060 | Is it feasible for an ectoparasite such as a a Tick to create a symbiotic relationship with its host? The hosts feeds the tick and the tick has some sort of beneficial substance within its saliva. This could be some sort of naturally evolved anti-fungal or anti-biotic. This relationship would allow those with the tick to out compete those without the tick due to superior disease resistance. | 2018/07/13 | [
"https://worldbuilding.stackexchange.com/questions/118060",
"https://worldbuilding.stackexchange.com",
"https://worldbuilding.stackexchange.com/users/42538/"
] | The medical use of parasites offers fascinating examples.
A [leech](https://en.wikipedia.org/wiki/Hirudo_medicinalis#Beneficial_secretions) is a parasite in general, but for certain health problems it has an effect that potentially outweighs the harm.
Immune suppressant [worms](https://en.wikipedia.org/wiki/Effects_of_parasitic_worms_on_the_immune_system#Positive_effects) presumably are big picture bad, but seem to give specific auto-immune and allergy sufferers less problems than they had before.
Additionally with some non-obvious conditions some strictly bad changes to an individuals potential to reproduce might be of positive value to their genes through relatives or already having offspring:
Some parasites modify the hosts reproduction to divert that energy to the parasite, if the parasite only takes most of that energy the social network of the host might come out ahead.
[Some parasites](https://www.ncbi.nlm.nih.gov/pubmed/15255095) compete with each other, resulting in a host less disadvantaged than having either parasite alone. Similarly in cases where one of the parasites kills the other(s) it might not be the one most deteriorates to the host. If (like most species including humans) there are a lot of common parasites a super parasite that wipes out the others might be a net win even if it ends up killing the host eventually. | Take a look at anglerfish. The female is this gigantic thing, and the male is super-tiny. He bites the female and gets embedded in there. In time, his body wastes away, and he's little more than a sack of sperm for the female to use when she needs eggs fertilized.
There are plenty of symbiotic relationships like this in the wild. Just think of something the host needs and something the symbiote needs where pairing would help both achieve their separate needs. |
118,060 | Is it feasible for an ectoparasite such as a a Tick to create a symbiotic relationship with its host? The hosts feeds the tick and the tick has some sort of beneficial substance within its saliva. This could be some sort of naturally evolved anti-fungal or anti-biotic. This relationship would allow those with the tick to out compete those without the tick due to superior disease resistance. | 2018/07/13 | [
"https://worldbuilding.stackexchange.com/questions/118060",
"https://worldbuilding.stackexchange.com",
"https://worldbuilding.stackexchange.com/users/42538/"
] | **Conditionally beneficial parasite.**
A cool thing for a fiction would be some parasite which was not beneficial but which caused some symptom that the host could use in a particular circumstance.
For example, toxoplasmosis.
<https://www.nature.com/news/parasite-makes-mice-lose-fear-of-cats-permanently-1.13777>
>
> A parasite that infects up to one-third of people around the world may
> have the ability to permanently alter a specific brain function in
> mice, according to a study published in PLoS ONE today1.
>
>
> Toxoplasma gondii is known to remove rodents’ innate fear of cats. The
> new research shows that even months after infection, when parasites
> are no longer detectable, the effect remains. This raises the
> possibility that the microbe causes a permanent structural change in
> the brain.
>
>
>
Crazy bravery like this means mice get eaten by cats. But suppose you were a warrior mouse and you craved the crazy brave. Maybe toxo in the brain could do that for you.
---
A real life example: hookworms to treat autoimmunity.
<https://www.theguardian.com/lifeandstyle/2010/may/23/parasitic-hookworm-jasper-lawrence-tim-adams>
>
> While in the field in Papua New Guinea in the late 1980s, Pritchard
> noted that patients infected with the Necator americanus hookworm were
> rarely subject to the whole range of autoimmune-related illnesses,
> including hay fever and asthma. In the years since, Pritchard had
> developed a thesis to support this observation through painstaking
> clinical trials (which began after he infected himself with 50
> hookworm). The thesis proved that hookworm, in small numbers, seemed
> able to regulate inflammatory immune responses in their hosts
>
>
>
Hookworms are looking out for their own interests by crippling the immune system of their host. But if the immune system of the host has gone rogue, crippling it up is helpful and apparently hookworms produce fewer side effects than pharmacologic methods accomplishing the same end.
---
So your parasite - it produces symptoms which advance its own cause. The parasite is not your friend. It cares only about itself. But can you use those symptoms to advance your cause too? I am reminded of the infected demon arm of Prince Ashitaka in Princess Mononoke. Not good in the long term, a demon arm. But very useful in the short term it turns out. | The medical use of parasites offers fascinating examples.
A [leech](https://en.wikipedia.org/wiki/Hirudo_medicinalis#Beneficial_secretions) is a parasite in general, but for certain health problems it has an effect that potentially outweighs the harm.
Immune suppressant [worms](https://en.wikipedia.org/wiki/Effects_of_parasitic_worms_on_the_immune_system#Positive_effects) presumably are big picture bad, but seem to give specific auto-immune and allergy sufferers less problems than they had before.
Additionally with some non-obvious conditions some strictly bad changes to an individuals potential to reproduce might be of positive value to their genes through relatives or already having offspring:
Some parasites modify the hosts reproduction to divert that energy to the parasite, if the parasite only takes most of that energy the social network of the host might come out ahead.
[Some parasites](https://www.ncbi.nlm.nih.gov/pubmed/15255095) compete with each other, resulting in a host less disadvantaged than having either parasite alone. Similarly in cases where one of the parasites kills the other(s) it might not be the one most deteriorates to the host. If (like most species including humans) there are a lot of common parasites a super parasite that wipes out the others might be a net win even if it ends up killing the host eventually. |
118,060 | Is it feasible for an ectoparasite such as a a Tick to create a symbiotic relationship with its host? The hosts feeds the tick and the tick has some sort of beneficial substance within its saliva. This could be some sort of naturally evolved anti-fungal or anti-biotic. This relationship would allow those with the tick to out compete those without the tick due to superior disease resistance. | 2018/07/13 | [
"https://worldbuilding.stackexchange.com/questions/118060",
"https://worldbuilding.stackexchange.com",
"https://worldbuilding.stackexchange.com/users/42538/"
] | **Conditionally beneficial parasite.**
A cool thing for a fiction would be some parasite which was not beneficial but which caused some symptom that the host could use in a particular circumstance.
For example, toxoplasmosis.
<https://www.nature.com/news/parasite-makes-mice-lose-fear-of-cats-permanently-1.13777>
>
> A parasite that infects up to one-third of people around the world may
> have the ability to permanently alter a specific brain function in
> mice, according to a study published in PLoS ONE today1.
>
>
> Toxoplasma gondii is known to remove rodents’ innate fear of cats. The
> new research shows that even months after infection, when parasites
> are no longer detectable, the effect remains. This raises the
> possibility that the microbe causes a permanent structural change in
> the brain.
>
>
>
Crazy bravery like this means mice get eaten by cats. But suppose you were a warrior mouse and you craved the crazy brave. Maybe toxo in the brain could do that for you.
---
A real life example: hookworms to treat autoimmunity.
<https://www.theguardian.com/lifeandstyle/2010/may/23/parasitic-hookworm-jasper-lawrence-tim-adams>
>
> While in the field in Papua New Guinea in the late 1980s, Pritchard
> noted that patients infected with the Necator americanus hookworm were
> rarely subject to the whole range of autoimmune-related illnesses,
> including hay fever and asthma. In the years since, Pritchard had
> developed a thesis to support this observation through painstaking
> clinical trials (which began after he infected himself with 50
> hookworm). The thesis proved that hookworm, in small numbers, seemed
> able to regulate inflammatory immune responses in their hosts
>
>
>
Hookworms are looking out for their own interests by crippling the immune system of their host. But if the immune system of the host has gone rogue, crippling it up is helpful and apparently hookworms produce fewer side effects than pharmacologic methods accomplishing the same end.
---
So your parasite - it produces symptoms which advance its own cause. The parasite is not your friend. It cares only about itself. But can you use those symptoms to advance your cause too? I am reminded of the infected demon arm of Prince Ashitaka in Princess Mononoke. Not good in the long term, a demon arm. But very useful in the short term it turns out. | Take a look at anglerfish. The female is this gigantic thing, and the male is super-tiny. He bites the female and gets embedded in there. In time, his body wastes away, and he's little more than a sack of sperm for the female to use when she needs eggs fertilized.
There are plenty of symbiotic relationships like this in the wild. Just think of something the host needs and something the symbiote needs where pairing would help both achieve their separate needs. |
118,060 | Is it feasible for an ectoparasite such as a a Tick to create a symbiotic relationship with its host? The hosts feeds the tick and the tick has some sort of beneficial substance within its saliva. This could be some sort of naturally evolved anti-fungal or anti-biotic. This relationship would allow those with the tick to out compete those without the tick due to superior disease resistance. | 2018/07/13 | [
"https://worldbuilding.stackexchange.com/questions/118060",
"https://worldbuilding.stackexchange.com",
"https://worldbuilding.stackexchange.com/users/42538/"
] | This is literally the definition of [symbiosis](https://en.wikipedia.org/wiki/Symbiosis). The only issue in your question, as pointed out in comments, is that a parasite is definitionally not a symbiote, as a parasite derives a benefit for itself while damaging its host. Symbiotic relationships involve benefits to both organisms.
There are tons of examples of this in the world right now. Think of [remora](https://en.wikipedia.org/wiki/Remora) cleaning sharks in order to feed themselves and avoid predators, or (again already mentioned in comments) mitochondria in animal cells.
From a worldbuilding perspective, the key elements are that both organisms derive a net benefit from the relationship, and exist in such a way that they can interact to produce those benefits (like living physically close enough to interact, as in the remora, or even becoming incorporated into the same larger organism, as in the mitochondria). The net benefit piece means that there can still be negative consequences to the interactions, just that the balance must tip towards the favorable. | Take a look at anglerfish. The female is this gigantic thing, and the male is super-tiny. He bites the female and gets embedded in there. In time, his body wastes away, and he's little more than a sack of sperm for the female to use when she needs eggs fertilized.
There are plenty of symbiotic relationships like this in the wild. Just think of something the host needs and something the symbiote needs where pairing would help both achieve their separate needs. |
118,060 | Is it feasible for an ectoparasite such as a a Tick to create a symbiotic relationship with its host? The hosts feeds the tick and the tick has some sort of beneficial substance within its saliva. This could be some sort of naturally evolved anti-fungal or anti-biotic. This relationship would allow those with the tick to out compete those without the tick due to superior disease resistance. | 2018/07/13 | [
"https://worldbuilding.stackexchange.com/questions/118060",
"https://worldbuilding.stackexchange.com",
"https://worldbuilding.stackexchange.com/users/42538/"
] | **Conditionally beneficial parasite.**
A cool thing for a fiction would be some parasite which was not beneficial but which caused some symptom that the host could use in a particular circumstance.
For example, toxoplasmosis.
<https://www.nature.com/news/parasite-makes-mice-lose-fear-of-cats-permanently-1.13777>
>
> A parasite that infects up to one-third of people around the world may
> have the ability to permanently alter a specific brain function in
> mice, according to a study published in PLoS ONE today1.
>
>
> Toxoplasma gondii is known to remove rodents’ innate fear of cats. The
> new research shows that even months after infection, when parasites
> are no longer detectable, the effect remains. This raises the
> possibility that the microbe causes a permanent structural change in
> the brain.
>
>
>
Crazy bravery like this means mice get eaten by cats. But suppose you were a warrior mouse and you craved the crazy brave. Maybe toxo in the brain could do that for you.
---
A real life example: hookworms to treat autoimmunity.
<https://www.theguardian.com/lifeandstyle/2010/may/23/parasitic-hookworm-jasper-lawrence-tim-adams>
>
> While in the field in Papua New Guinea in the late 1980s, Pritchard
> noted that patients infected with the Necator americanus hookworm were
> rarely subject to the whole range of autoimmune-related illnesses,
> including hay fever and asthma. In the years since, Pritchard had
> developed a thesis to support this observation through painstaking
> clinical trials (which began after he infected himself with 50
> hookworm). The thesis proved that hookworm, in small numbers, seemed
> able to regulate inflammatory immune responses in their hosts
>
>
>
Hookworms are looking out for their own interests by crippling the immune system of their host. But if the immune system of the host has gone rogue, crippling it up is helpful and apparently hookworms produce fewer side effects than pharmacologic methods accomplishing the same end.
---
So your parasite - it produces symptoms which advance its own cause. The parasite is not your friend. It cares only about itself. But can you use those symptoms to advance your cause too? I am reminded of the infected demon arm of Prince Ashitaka in Princess Mononoke. Not good in the long term, a demon arm. But very useful in the short term it turns out. | This is literally the definition of [symbiosis](https://en.wikipedia.org/wiki/Symbiosis). The only issue in your question, as pointed out in comments, is that a parasite is definitionally not a symbiote, as a parasite derives a benefit for itself while damaging its host. Symbiotic relationships involve benefits to both organisms.
There are tons of examples of this in the world right now. Think of [remora](https://en.wikipedia.org/wiki/Remora) cleaning sharks in order to feed themselves and avoid predators, or (again already mentioned in comments) mitochondria in animal cells.
From a worldbuilding perspective, the key elements are that both organisms derive a net benefit from the relationship, and exist in such a way that they can interact to produce those benefits (like living physically close enough to interact, as in the remora, or even becoming incorporated into the same larger organism, as in the mitochondria). The net benefit piece means that there can still be negative consequences to the interactions, just that the balance must tip towards the favorable. |
548,053 | I have the following circuit with a photodiode and an LM358P where I intend to blink an LED at around 20kHz. I want to work on it. I have made a calculation through 1/(2piRC), and got something around 33khz. Is this correct? Will this circuit work with a 20kHz frequency ?
[](https://i.stack.imgur.com/j4in2.jpg) | 2021/02/13 | [
"https://electronics.stackexchange.com/questions/548053",
"https://electronics.stackexchange.com",
"https://electronics.stackexchange.com/users/197447/"
] | >
> *got something around 33khz. Is this correct? Will this circuit work
> with a 20kHz frequency ?*
>
>
>
It's nearer 34 kHz but yes this will do the job adequately with some rounding of the output signal.
However, the output signal will clip at around 3 volts typically with an LM358 and, that op-amp will introduce some extra low pass filtering due to its small bandwidth and slew rate limitations on the output: -
[](https://i.stack.imgur.com/V9YI2.png) | It can work if your LED generates enough right wavelength light to the diode. I suspect that other lights disturb the function substantially. To avoid it you should use a circuit which doesn't amplify DC and the flicker of mains AC operated lights. For good sensitivity you should have a filter which removes unwanted signals. It should be placed in front of the actual amp if your LED is weak compared to ambient light. 47kOhm resistor is quite small, but that can well work in strong light or with sensitive diode.
BTW your capacitor causes lowpass filtering which doesn't help at all against low frequency nor continuous disturbing lights. |
373 | I have [asked this question](https://hardwarerecs.stackexchange.com/questions/1192/where-civilian-can-get-most-powerful-laser) today and moderator closed [it because](https://hardwarerecs.stackexchange.com/questions/1192/where-civilian-can-get-most-powerful-laser#comment-2499)
>
> I'm closing this question because we don't tend to deal with
> recommendations of manufacturers or stores, only hardware. You can
> rephrase the question to ask for the hardware itself, and we may be
> able to reopen it, though in not sure if losers are on topic.
>
>
>
**If moderator is unsure if type of hardware (like 'losers') is on topic shouldn't he first make sure if they are or not and then go around closing questions?**
[from tour:](https://hardwarerecs.stackexchange.com/tour)
>
> Ask about...
>
>
> specific hardware that would enable you to perform a certain task
>
>
>
Most powerful laser to fry stuff.
>
> Don't ask about...
>
>
> Technical support of any kind
>
> Step-by-step instructions for "do-it-yourself" installation
>
> Anything not directly related to recommending hardware
>
> Questions that are primarily opinion-based
>
> Questions with too many possible answers or that would require an
> extremely long answer
>
>
> | 2015/11/12 | [
"https://hardwarerecs.meta.stackexchange.com/questions/373",
"https://hardwarerecs.meta.stackexchange.com",
"https://hardwarerecs.meta.stackexchange.com/users/924/"
] | Really? You're calling this on a typo?
1. "Lasers", not "losers".
2. Please take a look at [What is Hardware?](https://hardwarerecs.meta.stackexchange.com/questions/265/what-is-hardware). It details what's in scope. Lasers are neither a primary computing platform nor directly designed to interface with one, therefore are off topic.
The tour can't cover everything, and the "ask about" points certainly don't. We haven't had any questions about recommending stores or markets yet, so we hadn't thought to put them in "don't ask about".
Since you're also complaining about your comments being deleted, I'll explain that too. I deleted a few comments on your question on main because
* they were getting chatty, which is not what comments are for
* and in one of them, you had a go at trying to reveal my real name, which is **Not On**.
I also deleted precisely one of your comments here on Meta, because you weren't Being Nice. If they weren't being used as examples to support another meta post, I would delete a few more here for the same reason. | As a fellow moderator, I fully support ArtOfCode's decision here. If I'd been awake at the time, I would have closed it for the same reason - if I'm not sure that something is off topic in one aspect, but I *know* it is in another aspect, it's off topic. |
70,878 | John 7:37-38 ESV
>
> 37 On the last day of the feast, the great day, Jesus stood up and cried out, “If anyone thirsts, let him come to me and drink. 38 Whoever believes in me, as[f] the Scripture has said, ‘Out of his heart will flow rivers of living water.’”
>
>
>
We are told that during the feast of Booths Christ cried out extending an invitation to those who are thirst.The text describes the invitation as referring to the giving of the Holy spirit,yet later in the same book it seems the coming of the the Holy spirit is connected to Christ ascension
John 16:7 ESV
>
> 7 Nevertheless, I tell you the truth: it is to your advantage that I go away, ***for if I do not go away, the Helper will not come to you***. But if I go, I will send him to you.
>
>
>
Did Christ intend giving the Holy spirit prior to his ascension? | 2021/11/05 | [
"https://hermeneutics.stackexchange.com/questions/70878",
"https://hermeneutics.stackexchange.com",
"https://hermeneutics.stackexchange.com/users/16527/"
] | John 7:
>
> 37 On the last and greatest day of the festival, Jesus stood and said in a loud voice, “Let anyone who is thirsty come to me and drink. 38Whoever believes in me, as Scripture has said, rivers of living water will flow from within them.” 39By this he meant the Spirit, whom those who believed in him were later to receive. Up to that time the Spirit had not been given, since Jesus had not yet been **glorified**.
>
>
>
i.e., glorified on the cross. The Spirit here refers to the special function of the Paraclete, the indwelling Holy Spirit. This is confirmed later in
John 16:
>
> 7 Nevertheless, I tell you the truth: it is to your advantage that I go away, for if I do not go away, the **Helper** [Paraclete] will not come to you. But if I go, I will send him to you.
>
>
>
Did Christ intend giving the Holy spirit prior to his ascension?
not in the special function of the Paraclete. | The giving of the Holy Spirit to all believers as a component of their salvation was not given prior to the ascension. However there is multiple pieces of new and old testament evidence for the presence and action of the Holy Spirit prior to Jesus' ministry, including creation (Genesis 1:2), Gideon (Numbers 6:34), and John the Baptist (Luke 1:15). I hope this answered your question. Keep studying :) |
70,878 | John 7:37-38 ESV
>
> 37 On the last day of the feast, the great day, Jesus stood up and cried out, “If anyone thirsts, let him come to me and drink. 38 Whoever believes in me, as[f] the Scripture has said, ‘Out of his heart will flow rivers of living water.’”
>
>
>
We are told that during the feast of Booths Christ cried out extending an invitation to those who are thirst.The text describes the invitation as referring to the giving of the Holy spirit,yet later in the same book it seems the coming of the the Holy spirit is connected to Christ ascension
John 16:7 ESV
>
> 7 Nevertheless, I tell you the truth: it is to your advantage that I go away, ***for if I do not go away, the Helper will not come to you***. But if I go, I will send him to you.
>
>
>
Did Christ intend giving the Holy spirit prior to his ascension? | 2021/11/05 | [
"https://hermeneutics.stackexchange.com/questions/70878",
"https://hermeneutics.stackexchange.com",
"https://hermeneutics.stackexchange.com/users/16527/"
] | The answer to this question is in the next verse so let me quote the John 7:37-39 -
>
> **37** On the last and greatest day of the feast, Jesus stood up and called out in a loud voice, “If anyone is thirsty, let him come to Me
> and drink. **38** Whoever believes in Me, as the Scripture has said:
> ‘Streams of living water will flow from within him.’ ” **39** He was
> speaking about the Spirit, whom those who believed in Him **were later
> to receive**. **For the Spirit had not yet been given, because Jesus
> had not yet been glorified**.
>
>
>
Thus, there is nothing inconsistent between John 7:37-39 and the other references to the Holy Spirit in John 14:16, 26, 15:26, 16:7 that likens the Holy Spirit to an Advocate, Helper, comforter, or "paraklete" in Greek.
The Holy Spirit would come "with power" (Acts 1:8, 10:38, Eph 3:16, 1 Thess 1:5, Rom 1:4, 15:19, etc) only after Jesus' ascension as described in Luke 24:49 (NLT) -
>
> “And now I will send the Holy Spirit, just as my Father promised. But
> stay here in the city until the Holy Spirit comes and fills you with
> power from heaven.”
>
>
>
And also in John 20:21, 22 after the resurrection -
>
> Jesus said to them again, “Peace be with you. As the Father has sent
> me, even so I am sending you.” And when he had said this, he breathed
> on them and said to them, “Receive the Holy Spirit.
>
>
> | The giving of the Holy Spirit to all believers as a component of their salvation was not given prior to the ascension. However there is multiple pieces of new and old testament evidence for the presence and action of the Holy Spirit prior to Jesus' ministry, including creation (Genesis 1:2), Gideon (Numbers 6:34), and John the Baptist (Luke 1:15). I hope this answered your question. Keep studying :) |
70,878 | John 7:37-38 ESV
>
> 37 On the last day of the feast, the great day, Jesus stood up and cried out, “If anyone thirsts, let him come to me and drink. 38 Whoever believes in me, as[f] the Scripture has said, ‘Out of his heart will flow rivers of living water.’”
>
>
>
We are told that during the feast of Booths Christ cried out extending an invitation to those who are thirst.The text describes the invitation as referring to the giving of the Holy spirit,yet later in the same book it seems the coming of the the Holy spirit is connected to Christ ascension
John 16:7 ESV
>
> 7 Nevertheless, I tell you the truth: it is to your advantage that I go away, ***for if I do not go away, the Helper will not come to you***. But if I go, I will send him to you.
>
>
>
Did Christ intend giving the Holy spirit prior to his ascension? | 2021/11/05 | [
"https://hermeneutics.stackexchange.com/questions/70878",
"https://hermeneutics.stackexchange.com",
"https://hermeneutics.stackexchange.com/users/16527/"
] | John 7:
>
> 37 On the last and greatest day of the festival, Jesus stood and said in a loud voice, “Let anyone who is thirsty come to me and drink. 38Whoever believes in me, as Scripture has said, rivers of living water will flow from within them.” 39By this he meant the Spirit, whom those who believed in him were later to receive. Up to that time the Spirit had not been given, since Jesus had not yet been **glorified**.
>
>
>
i.e., glorified on the cross. The Spirit here refers to the special function of the Paraclete, the indwelling Holy Spirit. This is confirmed later in
John 16:
>
> 7 Nevertheless, I tell you the truth: it is to your advantage that I go away, for if I do not go away, the **Helper** [Paraclete] will not come to you. But if I go, I will send him to you.
>
>
>
Did Christ intend giving the Holy spirit prior to his ascension?
not in the special function of the Paraclete. | >
> Now this he (Jesus) said about the spirit, whom those who believed in him were to receive, for as yet the spirit had not been given, because Jesus was not yet glorified. John 7:39
>
>
>
>
> Exalted then, to the right hand of God, he has received from the Father the promised holy spirit and has poured out what you now see and hear. Acts 2:33
>
>
>
There is no indication that we can conclude from John 7:37 that this concerns a *time* for this event. Other verses do give a time. The verses noted should be the primary reference for understanding this matter.
An invitation is not the same as the actual event and so no contradiction or uncertainty is evident.
Jesus in his pre-ascended, pre-crucifixion, mortal state of humanity is not able to grant such a thing as the spirit of God - unless God grants it through him as He did through the prophets etc. Once exalted, Jesus has the power within himself because God has given that to him. |
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