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https://en.wikipedia.org/wiki/Digraphs%20and%20trigraphs | In computer programming, digraphs and trigraphs are sequences of two and three characters, respectively, that appear in source code and, according to a programming language's specification, should be treated as if they were single characters.
Various reasons exist for using digraphs and trigraphs: keyboards may not have keys to cover the entire character set of the language, input of special characters may be difficult, text editors may reserve some characters for special use and so on. Trigraphs might also be used for some EBCDIC code pages that lack characters such as { and }.
History
The basic character set of the C programming language is a subset of the ASCII character set that includes nine characters which lie outside the ISO 646 invariant character set. This can pose a problem for writing source code when the encoding (and possibly keyboard) being used does not support any of these nine characters. The ANSI C committee invented trigraphs as a way of entering source code using keyboards that support any version of the ISO 646 character set.
Implementations
Trigraphs are not commonly encountered outside compiler test suites. Some compilers support an option to turn recognition of trigraphs off, or disable trigraphs by default and require an option to turn them on. Some can issue warnings when they encounter trigraphs in source files. Borland supplied a separate program, the trigraph preprocessor (TRIGRAPH.EXE), to be used only when trigraph processing is desired (the rationale was to maximise speed of compilation).
Language support
Different systems define different sets of digraphs and trigraphs, as described below.
ALGOL
Early versions of ALGOL predated the standardized ASCII and EBCDIC character sets, and were typically implemented using a manufacturer-specific six-bit character code. A number of ALGOL operations either lacked codepoints in the available character set or were not supported by peripherals, leading to a number of substitutions including := for ← (assignment) and >= for ≥ (greater than or equal).
Pascal
The Pascal programming language supports digraphs (., .), (* and *) for [, ], { and } respectively. Unlike all other cases mentioned here, (* and *) were and still are in wide use. However, many compilers treat them as a different type of commenting block rather than as actual digraphs, that is, a comment started with (* cannot be closed with } and vice versa.
J
The J programming language is a descendant of APL but uses the ASCII character set rather than APL symbols. Because the printable range of ASCII is smaller than APL's specialized set of symbols, . (dot) and : (colon) characters are used to inflect ASCII symbols, effectively interpreting unigraphs, digraphs or rarely trigraphs as standalone "symbols".
Unlike the use of digraphs and trigraphs in C and C++, there are no single-character equivalents to these in J.
C
The C preprocessor (used for C and with slight differences in C++; see below) replaces al |
https://en.wikipedia.org/wiki/Jim%20Hall%20%28computer%20programmer%29 | Jim Hall (James F. Hall) is a computer programmer and advocate of free software, best known for his work on FreeDOS. Hall began writing the free replacement for the MS-DOS operating system in 1994 when he was still a physics student at the University of Wisconsin-River Falls. He remains active with FreeDOS, and is currently the coordinator for the project.
Hall has said he created FreeDOS in response to Microsoft announcing end of support for MS-DOS in 1994, a year before Windows 95 was released. As a user and fan of MS-DOS, Hall did not want the functionality of DOS to go away. Prompted by a March 31, 1994 post on comp.os.msdos.misc asking if "anyone, for example GNU et al. ever considered writing a Public Domain DOS", Hall decided to garner support for a free version of DOS, written under a free or public domain model. In a June 29, 1994 post, Hall announced an effort to create a free DOS, called PD-DOS, writing:
Within a few weeks, other programmers including Pat Villani and Tim Norman joined the project. A kernel, the COMMAND.COM command line interpreter (shell) and core utilities were created by pooling code they had written or found available. Hall wrote over a dozen of the first DOS utilities for the project, mostly file and batch utilities. In a July 26, 1994 post, Hall announced the PD-DOS project had been renamed to "Free-DOS", having updated the project's goals to intend to distribute source code under the GNU General Public License. The project would later be renamed "FreeDOS", without the hyphen, after the publication of FreeDOS Kernel, by Pat Villani. Hall was the project's release coordinator from Beta1 until about Beta7, and also released the first alpha distribution of Free-DOS, as announced in a post on comp.os.msdos.misc. He is again the project coordinator since April 2011 after Pat Villani's departure, and subsequent death in August of the same year.
Hall is also the original developer of GNU Robots, but he is no longer active on this project and has since handed maintainership over to Tim Northover. It is now being developed by Bradley Smith.
References
Further reading
External links
Free software programmers
American computer programmers
FreeDOS people
People from Virginia
University of Wisconsin–River Falls alumni
20th-century births
Living people
Year of birth missing (living people) |
https://en.wikipedia.org/wiki/EPL | EPL may refer to:
Computing
Easy Programming Language
Eclipse Public License
Eltron Programming Language, a control language for various computer printers
Ethernet Powerlink, an Ethernet protocol
Early PL/I, a PL/I subset dialect used to write Multics
Anatomy
Extensor pollicis longus muscle
External plexiform layer
Education
École polytechnique de Louvain, faculty of engineering science at the University of Louvain (UCLouvain), Belgium
Libraries
Edmonton Public Library, in Alberta, Canada
Euclid Public Library, in, Ohio, United States
Evanston Public Library, in Illinois, United States
Everett Public Library, in Washington, United States
Publications
EPL (journal), a scientific journal
Eesti Päevaleht, an Estonian newspaper
Sports
Egyptian Premier League
English Premier League
ESL Pro League, a professional Counter-Strike: Global Offensive league
Everest Premier League, a Nepali cricket league
Other uses
Edinburgh Partners, a Scottish investment firm
El Pollo Loco, an American restaurant chain
Employment practices liability
Employment protection legislation
Escola Portuguesa de Luanda, a Portuguese international school in Angola
Popular Liberation Army (Spanish: ), a Colombian guerrilla group |
https://en.wikipedia.org/wiki/Neats%20and%20scruffies | In the history of artificial intelligence, neat and scruffy are two contrasting approaches to artificial intelligence (AI) research. The distinction was made in the 70s and was a subject of discussion until the middle 80s.
"Neats" use algorithms based on a single formal paradigms, such as logic, mathematical optimization or neural networks. Neats verify their programs are correct with theorems and mathematical rigor. Neat researchers and analysts tend to express the hope that this single formal paradigm can be extended and improved to achieve general intelligence and superintelligence.
"Scruffies" use any number of different algorithms and methods to achieve intelligent behavior. Scruffies rely on incremental testing to verify their programs and scruffy programming requires large amounts of hand coding or knowledge engineering. Scruffies have argued that general intelligence can only be implemented by solving a large number of essentially unrelated problems, and that there is no magic bullet that will allow programs to develop general intelligence autonomously.
John Brockman compares the neat approach to physics, in that it uses simple mathematical models as its foundation. The scruffy approach is more like biology, where much of the work involves studying and categorizing diverse phenomena.
Modern AI has elements of both scruffy and neat approaches. In the 1990s AI research applied mathematical rigor to their programs, as the neats did. They also express the hope that there is a single paradigm (a "master algorithm") that will cause general intelligence and superintelligence to emerge. But modern AI also resembles the scruffies: modern machine learning applications require a great deal of hand-tuning and incremental testing; while the general algorithm is mathematically rigorous, accomplishing the specific goals of a particular application is not. Also, in the early 2000s, the field of software development embraced extreme programming, which is a modern version of the scruffy methodology -- try things and test them, without wasting time looking for more elegant or general solutions.
Origin in the 1970s
The distinction between neat and scruffy originated in the mid-1970s, by Roger Schank. Schank used the terms to characterize the difference between his work on natural language processing (which represented commonsense knowledge in the form of large amorphous semantic networks) from the work of John McCarthy, Allen Newell, Herbert A. Simon, Robert Kowalski and others whose work was based on logic and formal extensions of logic. Schank described himself as an AI scruffy. He made this distinction in linguistics, arguing strongly against Chomsky's view of language.
The distinction was also partly geographical and cultural: "scruffy" attributes were exemplified by AI research at MIT under Marvin Minsky in the 1970s. The laboratory was famously "freewheeling" and researchers often developed AI programs by spending long hours fine-tuning progr |
https://en.wikipedia.org/wiki/Computing%20Machinery%20and%20Intelligence | "Computing Machinery and Intelligence" is a seminal paper written by Alan Turing on the topic of artificial intelligence. The paper, published in 1950 in Mind, was the first to introduce his concept of what is now known as the Turing test to the general public.
Turing's paper considers the question "Can machines think?" Turing says that since the words "think" and "machine" cannot be clearly defined we should "replace the question by another, which is closely related to it and is expressed in relatively unambiguous words." To do this, he must first find a simple and unambiguous idea to replace the word "think", second he must explain exactly which "machines" he is considering, and finally, armed with these tools, he formulates a new question, related to the first, that he believes he can answer in the affirmative.
Turing's test
Rather than trying to determine if a machine is thinking, Turing suggests we should ask if the machine can win a game, called the "Imitation Game". The original Imitation game, that Turing described, is a simple party game involving three players. Player A is a man, player B is a woman and player C (who plays the role of the interrogator) can be of either sex. In the Imitation Game, player C is unable to see either player A or player B (and knows them only as X and Y), and can communicate with them only through written notes or any other form that does not give away any details about their gender. By asking questions of player A and player B, player C tries to determine which of the two is the man and which is the woman. Player A's role is to trick the interrogator into making the wrong decision, while player B attempts to assist the interrogator in making the right one.
Turing proposes a variation of this game that involves the computer: What will happen when a machine takes the part of A in this game?" Will the interrogator decide wrongly as often when the game is played like this as he does when the game is played between a man and a woman? These questions replace our original, 'Can machines think?
So the modified game becomes one that involves three participants in isolated rooms: a computer (which is being tested), a human, and a (human) judge. The human judge can converse with both the human and the computer by typing into a terminal. Both the computer and human try to convince the judge that they are the human. If the judge cannot consistently tell which is which, then the computer wins the game.
As Stevan Harnad notes, the question has become "Can machines do what we (as thinking entities) can do?" In other words, Turing is no longer asking whether a machine can "think"; he is asking whether a machine can act indistinguishably from the way a thinker acts. This question avoids the difficult philosophical problem of pre-defining the verb "to think" and focuses instead on the performance capacities that being able to think makes possible, and how a causal system can generate them.
Some have taken Turing's que |
https://en.wikipedia.org/wiki/Logical%20block%20addressing | Logical block addressing (LBA) is a common scheme used for specifying the location of blocks of data stored on computer storage devices, generally secondary storage systems such as hard disk drives. LBA is a particularly simple linear addressing scheme; blocks are located by an integer index, with the first block being LBA 0, the second LBA 1, and so on.
The IDE standard included 22-bit LBA as an option, which was further extended to 28-bit with the release of ATA-1 (1994) and to 48-bit with the release of ATA-6 (2003), whereas the size of entries in on-disk and in-memory data structures holding the address is typically 32 or 64 bits. Most hard disk drives released after 1996 implement logical block addressing.
Overview
In logical block addressing, only one number is used to address data, and each linear base address describes a single block.
The LBA scheme replaces earlier schemes which exposed the physical details of the storage device to the software of the operating system. Chief among these was the cylinder-head-sector (CHS) scheme, where blocks were addressed by means of a tuple which defined the cylinder, head, and sector at which they appeared on the hard disk. CHS did not map well to devices other than hard disks (such as tapes and networked storage), and was generally not used for them. CHS was used in early MFM and RLL drives, and both it and its successor, extended cylinder-head-sector (ECHS), were used in the first ATA drives. However, current disk drives use zone bit recording, where the number of sectors per track depends on the track number. Even though the disk drive will report some CHS values as sectors per track (SPT) and heads per cylinder (HPC), they have little to do with the disk drive's true geometry.
LBA was first introduced in SCSI as an abstraction. While the drive controller still addresses data blocks by their CHS address, this information is generally not used by the SCSI device driver, the OS, filesystem code, or any applications (such as databases) that access the "raw" disk. System calls requiring block-level I/O pass LBA definitions to the storage device driver; for simple cases (where one volume maps to one physical drive), this LBA is then passed directly to the drive controller.
In redundant array of independent disks (RAID) devices and storage area networks (SANs) and where logical drives (logical unit numbers, LUNs) are composed via LUN virtualization and aggregation, LBA addressing of individual disk should be translated by a software layer to provide uniform LBA addressing for the entire storage device.
Enhanced BIOS
The earlier IDE standard from Western Digital introduced 22-bit LBA; in 1994, the ATA-1 standard allowed for 28 bit addresses in both LBA and CHS modes. The CHS scheme used 16 bits for cylinder, 4 bits for head and 8 bits for sector, counting sectors from 1 to 255. This means the reported number of heads never exceeds 16 (0–15), the number of sectors can be 255 (1–255; though 6 |
https://en.wikipedia.org/wiki/FreeTDS | FreeTDS is a free software programming library, a re-implementation of the Tabular Data Stream protocol. It can be used in place of Sybase's db-lib or ct-lib libraries. It also includes an ODBC library. It allows many open source applications such as Perl and PHP (or any C or C++ program) to connect to Sybase ASE or Microsoft SQL Server.
FreeTDS is a source code library, not a program in and of itself. Users generally compile the library from source and link another program to the library to allow the other program to use the FreeTDS API. However, recent releases of FreeTDS do include some client programs, such as (a replacement for the utility programs distributed by Sybase and Microsoft). FreeTDS is licensed under terms of the GNU Lesser General Public License.
For scripting languages, FreeTDS is used in conjunction with a module for that language such as DBD::Sybase in Perl, Python-Sybase for Python, or Ruby DBI for Ruby
jTDS is a Java implementation of FreeTDS, available on SourceForge. jBCP extends jTDS to include Sybase Bulk Copy Program (BCP) extensions.
External links
C libraries
jTDS site on Sourceforge
jbcp site on Sourceforge
TDS++, A set of FreeTDS C++ Wrapper classes, licensed under LGPL
DBD::Sybase
Python-Sybase
Ruby DBI
C (programming language) libraries |
https://en.wikipedia.org/wiki/Tabular%20Data%20Stream | Tabular Data Stream (TDS) is an application layer protocol used to transfer data between a database server and a client. It was initially designed and developed by Sybase Inc. for their Sybase SQL Server relational database engine in 1984, and later by Microsoft in Microsoft SQL Server.
History
During the early development of Sybase SQL Server, the developers at Sybase perceived the lack of a commonly accepted application level protocol to transfer data between a database server and its client. In order to encourage the use of its products, Sybase promoted the use of a flexible pair of libraries, called netlib and db-lib, to implement standard SQL. A further library was included in order to implement "Bulk Copy" called blk. While netlib's job is to ferry data between the two computers through the underlying network protocol, db-lib provides an API to the client program, and communicates with the server via netlib. db-lib sends to the server a structured stream of bytes meant for tables of data, hence a Tabular Data Stream. blk provides, like db-lib, an API to the client programs and communicates with the server via netlib.
In 1990 Sybase entered into a technology-sharing agreement with Microsoft which resulted in Microsoft marketing its own SQL Server — Microsoft SQL Server — based on Sybase's code. Microsoft kept the db-lib API and added ODBC. (Microsoft has since added additional APIs.) At about the same time, Sybase introduced a more powerful successor to db-lib, called ct-lib, and called the pair Open Client. db-lib, though officially deprecated, remains in widespread use.
The TDS protocol comes in several varieties, most of which had not been openly documented because they were regarded as proprietary technology. The exception was TDS 5.0, used exclusively by Sybase, for which documentation is available from Sybase. This situation changed when Microsoft published the TDS specification in 2008, as part of the Open Specification Promise.
The FreeTDS team has developed a free native-library implementation of the TDS protocol, licensed under the LGPL license. WireShark has a protocol decoder for TDS.
Oracle Corporation provides Oracle Net - software analogous to TDS.
See also
Transact-SQL
References
External links
Microsoft Developer Network, Tabular Data Stream Protocol Specification
What is TDS?, sybase.com
FreeTDS
TinyTDS, Ruby bindings to FreeTDS.
jTDS, a pure-Java JDBC driver for TDS databases
jBCP, an extension of jTDS to include BCP protocols
United States Patent 7318075: Enhanced tabular data stream protocol, Microsoft
Patent: TRANSPORTING TABLE VALUED PARAMETER OVER TABULAR DATA STREAM PROTOCOL, Microsoft
Patent application: COMPRESSING NULL COLUMNS IN ROWS OF THE TABULAR DATA STREAM PROTOCOL, Microsoft
WireShark wiki: Protocol tds
Application layer protocols
Database access protocols |
https://en.wikipedia.org/wiki/Multiply%E2%80%93accumulate%20operation | In computing, especially digital signal processing, the multiply–accumulate (MAC) or multiply-add (MAD) operation is a common step that computes the product of two numbers and adds that product to an accumulator. The hardware unit that performs the operation is known as a multiplier–accumulator (MAC unit); the operation itself is also often called a MAC or a MAD operation. The MAC operation modifies an accumulator a:
When done with floating point numbers, it might be performed with two roundings (typical in many DSPs), or with a single rounding. When performed with a single rounding, it is called a fused multiply–add (FMA) or fused multiply–accumulate (FMAC).
Modern computers may contain a dedicated MAC, consisting of a multiplier implemented in combinational logic followed by an adder and an accumulator register that stores the result. The output of the register is fed back to one input of the adder, so that on each clock cycle, the output of the multiplier is added to the register. Combinational multipliers require a large amount of logic, but can compute a product much more quickly than the method of shifting and adding typical of earlier computers. Percy Ludgate was the first to conceive a MAC in his Analytical Machine of 1909, and the first to exploit a MAC for division (using multiplication seeded by reciprocal, via the convergent series ). The first modern processors to be equipped with MAC units were digital signal processors, but the technique is now also common in general-purpose processors.
In floating-point arithmetic
When done with integers, the operation is typically exact (computed modulo some power of two). However, floating-point numbers have only a certain amount of mathematical precision. That is, digital floating-point arithmetic is generally not associative or distributive. (See .)
Therefore, it makes a difference to the result whether the multiply–add is performed with two roundings, or in one operation with a single rounding (a fused multiply–add). IEEE 754-2008 specifies that it must be performed with one rounding, yielding a more accurate result.
Fused multiply–add
A fused multiply–add (FMA or fmadd)
is a floating-point multiply–add operation performed in one step (fused operation), with a single rounding. That is, where an unfused multiply–add would compute the product , round it to N significant bits, add the result to a, and round back to N significant bits, a fused multiply–add would compute the entire expression to its full precision before rounding the final result down to N significant bits.
A fast FMA can speed up and improve the accuracy of many computations that involve the accumulation of products:
Dot product
Matrix multiplication
Polynomial evaluation (e.g., with Horner's rule)
Newton's method for evaluating functions (from the inverse function)
Convolutions and artificial neural networks
Multiplication in double-double arithmetic
Fused multiply–add can usually be relied on to give more accu |
https://en.wikipedia.org/wiki/Kyushu%20Shinkansen | The is a Japanese Shinkansen high-speed railway network. It is an extension of the San'yō Shinkansen from Honshu connecting the city of Fukuoka (Hakata Station) in the north of Japan's Kyushu Island to the city of Kagoshima (Kagoshima-Chuo Station) in the south. The line runs parallel to the existing Kagoshima Main Line and is operated by Kyushu Railway Company (JR Kyushu).
The southernmost section of the track was constructed first, opening on 13 March 2004. The dual-track offered a significant improvement in transit time over the equivalent single-track section of the Kagoshima Main Line, despite the need for passengers to change to a Relay Tsubame narrow gauge train at Shin-Yatsushiro, and the remainder of the journey to Hakata Station. The northernmost section opened on 12 March 2011, enabling through-services to Shin-Osaka (and with an interchange, to Tokyo). However, opening ceremonies were cancelled due to the 2011 Tōhoku earthquake and tsunami.
The Nishi Kyushu Shinkansen route to Nagasaki (from to ) opened on 23 September 2022. A cross-platform interchange to a relay service called 'Relay Kamome' at Takeo-Onsen station offers a connection to Hakata.
Kagoshima Route
Construction of the began in 1991, and the first segment between Kagoshima and Shin-Yatsushiro opened on 13 March 2004. This initial section cut travel times between the two cities from 2 hours and 10 minutes to 35 minutes and reduced the time between Hakata and Kagoshima from 4 hours to 2 hours. When the entire line was completed, the travel time from Hakata to Kagoshima was further reduced to about an hour and 20 minutes. As of 2012, the maximum line speed is between Hakata and Kagoshima. Like all Shinkansen lines, the Kyushu Shinkansen is standard gauge.
The line's Sakura and Mizuho services often operate through to Shin-Ōsaka Station via the San'yō Shinkansen. All-stop trains are named Tsubame ("Swallow"), the name of the former Hakata-Kagoshima limited express service, and are solely truncated to the Kyushu Shinkansen.
In September 2011, six months after the line's completion, JR Kyushu reported a year-over-year increase in ridership of 64% to the southern part of Kyushu (between Kumamoto and Kagoshima), easily surpassing the 40% increase projected by the company. By the first anniversary, ridership had increased, mainly from tourists from Kansai and Chugoku. In northern Kyushu, where there is fierce competition with conventional JR rapid service, the private Nishi-Nippon Railroad, and expressway buses, Shinkansen ridership increased by only 38% (compared to the now-discontinued conventional express Relay Tsubame), falling short of estimates.
Nishi Kyushu (Nagasaki) Route
A Shinkansen line from Fukuoka to Nagasaki, initially known as the , was laid out in the 1973 Basic Plan. Renamed as the , then changed to the in 1995, the segment between and , Nishi Kyushu Shinkansen, opened for service on 23 September 2022.
Other planned routes
According to the Shinkan |
https://en.wikipedia.org/wiki/J%C3%BCrgen%20Schmidhuber | Jürgen Schmidhuber (born 17 January 1963) is a German computer scientist noted for his work in the field of artificial intelligence, specifically artificial neural networks. He is a scientific director of the Dalle Molle Institute for Artificial Intelligence Research in Switzerland. He is also director of the Artificial Intelligence Initiative and professor of the Computer Science program in the Computer, Electrical, and Mathematical Sciences and Engineering (CEMSE) division at the King Abdullah University of Science and Technology (KAUST) in Saudi Arabia.
He is best known for his foundational and highly-cited work on long short-term memory (LSTM), a type of neural network architecture which went on to become the dominant technique for various natural language processing tasks in research and commercial applications in the 2010s.
Career
Schmidhuber completed his undergraduate (1987) and PhD (1991) studies at the Technical University of Munich in Munich, Germany. His PhD advisors were Wilfried Brauer and Klaus Schulten. He taught there from 2004 until 2009. From 2009, until 2021, he was a professor of artificial intelligence at the Università della Svizzera Italiana in Lugano, Switzerland.
He has served as the director of Dalle Molle Institute for Artificial Intelligence Research (IDSIA), a Swiss AI lab, since 1995.
In 2014, Schmidhuber formed a company, Nnaisense, to work on commercial applications of artificial intelligence in fields such as finance, heavy industry and self-driving cars. Sepp Hochreiter, Jaan Tallinn, and Marcus Hutter are advisers to the company. Sales were under US$11 million in 2016; however, Schmidhuber states that the current emphasis is on research and not revenue. Nnaisense raised its first round of capital funding in January 2017. Schmidhuber's overall goal is to create an all-purpose AI by training a single AI in sequence on a variety of narrow tasks.
Research
In the 1980s, backpropagation did not work well for deep learning with long credit assignment paths in artificial neural networks. To overcome this problem, Schmidhuber (1991) proposed a hierarchy of recurrent neural networks (RNNs) pre-trained one level at a time by self-supervised learning. It uses predictive coding to learn internal representations at multiple self-organizing time scales. This can substantially facilitate downstream deep learning. The RNN hierarchy can be collapsed into a single RNN, by distilling a higher level chunker network into a lower level automatizer network. In 1993, a chunker solved a deep learning task whose depth exceeded 1000.
In 1991, Schmidhuber published adversarial neural networks that contest with each other in the form of a zero-sum game, where one network's gain is the other network's loss. The first network is a generative model that models a probability distribution over output patterns. The second network learns by gradient descent to predict the reactions of the environment to these patterns. This was called "art |
https://en.wikipedia.org/wiki/Low-complexity%20art | Low-complexity art, first described by Jürgen Schmidhuber in 1997 and now established as a seminal topic within the larger field of computer science, is art that can be described by a short computer program (that is, a computer program of small Kolmogorov complexity).
Overview
Schmidhuber characterizes low-complexity art as the computer age equivalent of minimal art. He also describes an algorithmic theory of beauty and aesthetics based on the principles of algorithmic information theory and minimum description length. It explicitly addresses the subjectivity of the observer and postulates that among several input data classified as comparable by a given subjective observer, the most pleasing one has the shortest description, given the observer's previous knowledge and his or her particular method for encoding the data. For example, mathematicians enjoy simple proofs with a short description in their formal language (sometimes called mathematical beauty). Another example draws inspiration from 15th century proportion studies by Leonardo da Vinci and Albrecht Dürer: the proportions of a beautiful human face can be described by very few bits of information.
Schmidhuber explicitly distinguishes between beauty and interestingness. He assumes that any observer continually tries to improve the predictability and compressibility of the observations by discovering regularities such as repetitions and symmetries and fractal self-similarity. When the observer's learning process (which may be a predictive neural network) leads to improved data compression the number of bits required to describe the data decreases. The temporary interestingness of the data corresponds to the number of saved bits, and thus (in the continuum limit) to the first derivative of subjectively perceived beauty. A reinforcement learning algorithm can be used to maximize the future expected data compression progress. It will motivate the learning observer to execute action sequences that cause additional interesting input data with yet unknown but learnable predictability or regularity. The principles can be implemented on artificial agents which then exhibit a form of artificial curiosity.
While low-complexity art does not require a priori restrictions of the description size, the basic ideas are related to the size-restricted intro categories of the demoscene, where very short computer programs are used to generate pleasing graphical and musical output. Very small (usually C) programs that create music have been written: the style of this music has come to be called "bytebeat".
The larger context
The larger context provided by the histories of both art and science suggests that low-complexity art will continue to be a topic of growing interest. In respect to art history, the potential relevance of low-complexity art extends far beyond the minimalistic Renaissance encoding of beauty already cited in its literature. The idea of an intimate relationship between mathematical st |
https://en.wikipedia.org/wiki/Digital%20physics | Digital physics is a speculative idea that the universe can be conceived of as a vast, digital computation device, or as the output of a deterministic or probabilistic computer program. The hypothesis that the universe is a digital computer was proposed by Konrad Zuse in his 1969 book Rechnender Raum ("Calculating Space"). The term digital physics was coined by Edward Fredkin in 1978, who later came to prefer the term digital philosophy. Fredkin encouraged the creation of a digital physics group at what was then MIT's Laboratory for Computer Science, with Tommaso Toffoli and Norman Margolus as primary figures.
Digital physics suggests that there exists, at least in principle, a program for a universal computer that computes the evolution of the universe. The computer could be, for example, a huge cellular automaton.
Extant models of digital physics are incompatible with the existence of several continuous characters of physical symmetries, e.g., rotational symmetry, translational symmetry, Lorentz symmetry, and the Lie group gauge invariance of Yang–Mills theories, all central to current physical theory. Moreover, extant models of digital physics violate various well-established features of quantum physics, belonging to the class of theories with local hidden variables that have so far been ruled out experimentally using Bell's theorem.
However, covariant discrete theories can be formulated that preserve the aforementioned symmetries.
See also
Mathematical universe hypothesis
It from bit
Simulation hypothesis
Weyl's tile argument
Natura non facit saltus
References
Further reading
Robert Wright, "Did the Universe Just Happen?", Atlantic Monthly, April 1988 - Article discussing Fredkin and his digital physics ideas
Theory of computation |
https://en.wikipedia.org/wiki/Edward%20Fredkin | Edward Fredkin (October 2, 1934 – June 13, 2023) was an American computer scientist, physicist and businessman who was an early pioneer of digital physics.
Fredkin's primary contributions included work on reversible computing and cellular automata. While Konrad Zuse's book, Calculating Space (1969), mentioned the importance of reversible computation, the Fredkin gate represented the essential breakthrough. In more recent work, he used the term digital philosophy (DP).
During his career, Fredkin was a professor of computer science at the Massachusetts Institute of Technology, a Fairchild Distinguished Scholar at Caltech, a distinguished career professor at Carnegie Mellon University, and a Research Professor of Physics at Boston University.
Early life and education
Fredkin's mother and father were both Russian immigrants who met in Los Angeles, and he was the youngest child of four. His mother was a concert pianist, although she did not perform professionally. She died from cancer when he was 11. His father was a businessperson but had lost everything in the 1929 stock market crash and as a result, the family was relatively poor. At times he lived with other families or with his older sister. Eventually, his father remarried, and he and his sister moved back in. As a child, he was both entrepreneurial and interested in science and how things work. He did various weekend and after-school things to earn money, eventually handling a large newspaper delivery route. At age 10 he bought chemistry supplies and made his own fireworks, which were then illegal in Los Angeles. He did poorly in school because he didn't do homework. He graduated from John Marshall High School a semester early so that he could earn money for Caltech tuition and living expenses. Caltech later told him he had been admitted with the worst high school grades they had ever seen. He quit Caltech partway through his sophomore year.
He then joined the United States Air Force (USAF) to become a fighter pilot. His computer career started in 1956 when the Air Force assigned him to MIT Lincoln Laboratory where he worked on the SAGE computer.
Career
Fredkin worked with a number of companies in the computer field and held academic positions at a number of universities. He was a computer programmer, a pilot, an advisor to businesses and governments, and a physicist. His main interests concerned digital computer-like models of basic processes in physics.
Fredkin's initial focus was physics; however, he became involved with computers in 1956 when he was sent by the Air Force, where he had trained as a jet pilot, to the MIT Lincoln Laboratory. On completing his service in 1958, Fredkin was hired by J. C. R. Licklider to work at the research firm, Bolt Beranek & Newman (BBN). After seeing the PDP-1 computer prototype at the Eastern Joint Computer Conference in Boston, in December 1959, Fredkin recommended that BBN purchase the very first PDP-1 to support research projects at BBN. The new |
https://en.wikipedia.org/wiki/Solomonoff%27s%20theory%20of%20inductive%20inference | Solomonoff's theory of inductive inference is a mathematical theory of induction introduced by Ray Solomonoff, based on probability theory and theoretical computer science. In essence, Solomonoff's induction derives the posterior probability of any computable theory, given a sequence of observed data. This posterior probability is derived from Bayes' rule and some universal prior, that is, a prior that assigns a positive probability to any computable theory.
Solomonoff's induction naturally formalizes Occam's razor by assigning larger prior credences to theories that require a shorter algorithmic description.
Origin
Philosophical
The theory is based in philosophical foundations, and was founded by Ray Solomonoff around 1960. It is a mathematically formalized combination of Occam's razor and the Principle of Multiple Explanations. All computable theories which perfectly describe previous observations are used to calculate the probability of the next observation, with more weight put on the shorter computable theories. Marcus Hutter's universal artificial intelligence builds upon this to calculate the expected value of an action.
Principle
Solomonoff's induction has been argued to be the computational formalization of pure Bayesianism. To understand, recall that Bayesianism derives the posterior probability of a theory given data by applying Bayes rule, which yields , where theories are alternatives to theory . For this equation to make sense, the quantities and must be well-defined for all theories and . In other words, any theory must define a probability distribution over observable data . Solomonoff's induction essentially boils down to demanding that all such probability distributions be computable.
Interestingly, the set of computable probability distributions is a subset of the set of all programs, which is countable. Similarly, the sets of observable data considered by Solomonoff were finite. Without loss of generality, we can thus consider that any observable data is a finite bit string. As a result, Solomonoff's induction can be defined by only invoking discrete probability distributions.
Solomonoff's induction then allows to make probabilistic predictions of future data , by simply obeying the laws of probability. Namely, we have . This quantity can be interpreted as the average predictions of all theories given past data , weighted by their posterior credences .
Mathematical
The proof of the "razor" is based on the known mathematical properties of a probability distribution over a countable set. These properties are relevant because the infinite set of all programs is a denumerable set. The sum S of the probabilities of all programs must be exactly equal to one (as per the definition of probability) thus the probabilities must roughly decrease as we enumerate the infinite set of all programs, otherwise S will be strictly greater than one. To be more precise, for every > 0, there is some length l such that the probabili |
https://en.wikipedia.org/wiki/EarthStation%205 | Earth Station 5 (ES5) was a peer-to-peer network active between 2003 and 2005, operated by a company of the same name. The user client application also shared this name. Earth Station 5 was notable for its strong, if overstated, emphasis on user anonymity, and for its bold advocacy of piracy and copyright infringement. ES5's highly antagonistic position toward copyright advocacy and enforcement organizations garnered the group significant attention and peaked with an ES5 press release announcing a "declaration of war" against the Motion Picture Association of America. ES5 claimed to operate out of the Jenin in the Palestinian Authority-controlled West Bank, a region where they argued that copyright laws were unenforceable. Investigative journalism cast serious doubts on the company's Palestinian origin as well as many of its other claims. To this day, much about the company and its leadership remains uncertain or unknown.
Peer-to-peer services
Earth Station 5 was based around a peer-to-peer (P2P) file sharing service and a standalone Earth Station 5 file-sharing client. Initial versions of the software could only share or download files by using the ES5 network.
ES5's P2P network and client were announced on June 9, 2003. People associated with ES5 claimed in media reports that the network had more than 16,000,000 participants at its peak, but these numbers were unsupported and viewed very skeptically. The actual number of participants was probably several orders of magnitude smaller.
Largely due to the low availability of files on the small ES5 network, later versions of the ES5 client included the free software/open source giFT daemon which provided ES5 users access to the larger Gnutella and FastTrack networks. While Gnutella and FastTrack offered access to many more files, the functionality that let users access these networks did not take advantage of any of ES5's anonymity features, which decreased the advantages of ES5 over other P2P clients — in particular other FastTrack or Gnutella clients.
ES5 software
The first version of the ES5 client used a space and spaceship motif and provided many options. In addition to several filesharing options, it provided links to chat, news, forums, dating functionality and news. The client interface was derided by reviewers as "clunky" and "a busy affair" for its plethora of features.
The second version of the client, released a year later, garnered better reviews. However, users still felt overwhelmed by the "bundled" features that included a dating service and audio-visual chat. ES5 claimed it planned to capitalize on these features in order to become profitable.
Claims to anonymity
ES5 became well known for its strong claims that file-sharing on its network was entirely anonymous — a feature it billed as its most important and revolutionary — and that its users could share files while remaining undetectable and thus invulnerable to lawsuits by the RIAA's member companies, which had recentl |
https://en.wikipedia.org/wiki/Web%20Feature%20Service | In computing, the Open Geospatial Consortium Web Feature Service (WFS) Interface Standard provides an interface allowing requests for geographical features across the web using platform-independent calls. One can think of geographical features as the "source code" behind a map, whereas the WMS interface or online tiled mapping portals like Google Maps return only an image, which end-users cannot edit or spatially analyze. The XML-based GML furnishes the default payload-encoding for transporting geographic features, but other formats like shapefiles can also serve for transport. In early 2006 the OGC members approved the OpenGIS GML Simple Features Profile. This profile is designed both to increase interoperability between WFS servers and to improve the ease of implementation of the WFS standard.
The OGC membership defined and maintains the WFS specification. Numerous commercial and open-source implementations of the WFS interface standard exist, including the open-source reference implementations GeoServer and deegree. The OGC Implementing Products page
provides a comprehensive list of WFS implementations.
Overview
The WFS specification defines interfaces for describing data manipulation operations of geographic features. Data manipulation operations include the ability to:
get or query features based on spatial and non-spatial constraints
create a new feature instance
delete a feature instance
update a feature instance
The basic Web Feature Service allows querying and retrieval of features. A transactional Web Feature Service (WFS-T) allows creation, deletion, and updating of features.
A WFS describes discovery, query, or data transformation operations. The client generates the request and posts it to a web feature server using HTTP. The web feature server then executes the request. The WFS specification uses HTTP as the distributed computing platform, although this is not a hard requirement.
There are two encodings defined for WFS operations:
XML (amenable to HTTP POST, or SOAP)
Key/value pairs (encoded in HTTP GET query strings, to perform remote procedure calls)
In the taxonomy of Web Services, WFS is best categorized as a non-RESTful RPC type service.
Communication models
The WFS Web Feature Services or Web Feature Server specification supports two communication models:
Stateless Request Reply
Pub/Sub
A messaging system in which clients address messages to a specific node in a content hierarchy, called a topic. Publishers and subscribers are generally anonymous and can dynamically publish or subscribe to the content hierarchy. The system takes care of distributing the messages arriving from a node's multiple publishers to its multiple subscribers. Messages are generally not persistent and will only be received by subscribers who are listening at the time the message is sent. A special case known as a “durable subscription” allows subscribers to receive messages sent while the subscribers are not active. (Source: Oracle Te |
https://en.wikipedia.org/wiki/They%27d%20Rather%20Be%20Right | They'd Rather Be Right (also known as The Forever Machine) is a science fiction novel by American writers Mark Clifton and Frank Riley.
Plot
Two professors create an advanced cybernetic brain, which they call "Bossy." Bossy can "optimise your mind...and give you eternal youth into the bargain, but only if you're ready to abandon all your favourite prejudices." However, when given the choice of admitting they were wrong and therefore being able to benefit from Bossy's abilities, most people would rather be right, and Bossy's ability to confer immortality is almost made ineffective by humanity's fear of "her."
Reception and significance
They'd Rather Be Right somewhat controversially won the Hugo Award for best novel in 1955, the second Hugo ever presented for a novel.
In a brief 1982 review of a contemporary reprint of the novel, author David Langford wrote that "though it contains an interesting idea, the book seems an implausible award-winner. It's fine (...) to postulate a machine giving immortality, youth and a perfect complexion to those and only those who can cast aside preconceptions and prejudices (...) The idea, though, is flattened into the ground by the authors' reluctance to do the work which would make it convincing."
Langford has also addressed conspiracy theories attributing They'd Rather Be Right's win to Scientology, saying it is more likely that Clifton was popular for his short stories.
Galaxy Science Fiction reviewer Floyd C. Gale faulted the novel, saying, "although a passably workmanlike job, loose ends outnumber neat knits in this yarn."
In 2008 Sam Jordison described the novel as "appalling," the "worst ever winner [of the Hugo Award]," and "a basic creative writing 'how not to,'" saying that its win "by public vote (...) raises serious questions about the value of a universal franchise." Similarly, author Lawrence Watt-Evans has stated that They'd Rather Be Right is "the usual [book] cited" as the "worst book ever to win [the Hugo Award]", and author Rick Cook responded to the question of "Is the book any good?" with "No," going on to explain its origins as "one of those tailored-to-order serials for the old Astounding. Sometimes those things worked and sometimes they didn't. This one didn't."
Publication history
They'd Rather Be Right was first published as a four-part serial in Astounding Science Fiction from August 1954 to November 1954. It was published as a book in 1957, and a heavily cut version was released the following year under the title The Forever Machine. The novel has been reprinted a few times in the decades since, including at least two foreign language translations.
They'd Rather Be Right is a sequel to "Crazy Joey" by Mark Clifton with Alex Apostolides
(August 1953, originally published in Astounding Science Fiction) and "Hide! Hide! Witch!" by Mark Clifton with Alex Apostolides (December 1953, originally published in Astounding Science Fiction).
The stories "Crazy Joey" and "Hide! Hide! Wi |
https://en.wikipedia.org/wiki/Flash%20drive | A flash drive is a portable computer drive that uses flash memory. Flash drives are the larger memory modules consisting of a number of flash chips. A flash chip is used to read the contents of a single cell, but it can write entire block of cells. They connect to a USB port and function as a folder.
Specific flash drive types
Memory cards:
Flash memory-based CompactFlash (CF) card (including CFast card) and XQD card (Note: some other types of CF and XQD card are not flash memory-based)
Memory Stick (MS)
MultiMediaCard (MMC)
Secure Digital card (SD, SDHC, SDXC)
SmartMedia card (SM)
xD-Picture Card (xD)
Other:
Solid-state drive, SSD, using flash memory (a few SSDs use DRAM or MRAM)
USB flash drive (UFD)
See also
Flash memory
Comparison of memory cards
References
Solid-state computer storage media |
https://en.wikipedia.org/wiki/AKS%20primality%20test | The AKS primality test (also known as Agrawal–Kayal–Saxena primality test and cyclotomic AKS test) is a deterministic primality-proving algorithm created and published by Manindra Agrawal, Neeraj Kayal, and Nitin Saxena, computer scientists at the Indian Institute of Technology Kanpur, on August 6, 2002, in an article titled "PRIMES is in P". The algorithm was the first one which is able to determine in polynomial time, whether a given number is prime or composite and this without relying on mathematical conjectures such as the generalized Riemann hypothesis. The proof is also notable for not relying on the field of analysis. In 2006 the authors received both the Gödel Prize and Fulkerson Prize for their work.
Importance
AKS is the first primality-proving algorithm to be simultaneously general, polynomial-time, deterministic, and unconditionally correct. Previous algorithms had been developed for centuries and achieved three of these properties at most, but not all four.
The AKS algorithm can be used to verify the primality of any general number given. Many fast primality tests are known that work only for numbers with certain properties. For example, the Lucas–Lehmer test works only for Mersenne numbers, while Pépin's test can be applied to Fermat numbers only.
The maximum running time of the algorithm can be bounded by a polynomial over the number of digits in the target number. ECPP and APR conclusively prove or disprove that a given number is prime, but are not known to have polynomial time bounds for all inputs.
The algorithm is guaranteed to distinguish deterministically whether the target number is prime or composite. Randomized tests, such as Miller–Rabin and Baillie–PSW, can test any given number for primality in polynomial time, but are known to produce only a probabilistic result.
The correctness of AKS is not conditional on any subsidiary unproven hypothesis. In contrast, Miller's version of the Miller–Rabin test is fully deterministic and runs in polynomial time over all inputs, but its correctness depends on the truth of the yet-unproven generalized Riemann hypothesis.
While the algorithm is of immense theoretical importance, it is not used in practice, rendering it a galactic algorithm. For 64-bit inputs, the Baillie–PSW test is deterministic and runs many orders of magnitude faster. For larger inputs, the performance of the (also unconditionally correct) ECPP and APR tests is far superior to AKS. Additionally, ECPP can output a primality certificate that allows independent and rapid verification of the results, which is not possible with the AKS algorithm.
Concepts
The AKS primality test is based upon the following theorem: Given an integer and integer coprime to , is prime if and only if the polynomial congruence relation
holds within the polynomial ring . Note that denotes the indeterminate which generates this polynomial ring.
This theorem is a generalization to polynomials of Fermat's little theorem. In one d |
https://en.wikipedia.org/wiki/Computer-aided%20dispatch | Computer-aided dispatch (CAD), also called computer-assisted dispatch, is a method of dispatching taxicabs, couriers, field service technicians, mass transit vehicles or emergency services assisted by computer. It can either be used to send messages to the dispatchee via a mobile data terminal (MDT) and/or used to store and retrieve data (i.e. radio logs, field interviews, client information, schedules, etc.). A dispatcher may announce the call details to field units over a two-way radio. Some systems communicate using a two-way radio system's selective calling features. CAD systems may send text messages with call-for-service details to alphanumeric pagers or wireless telephony text services like SMS. The central idea is that persons in a dispatch center are able to easily view and understand the status of all units being dispatched. CAD provides displays and tools so that the dispatcher has an opportunity to handle calls-for-service as efficiently as possible.
CAD typically consists of a suite of software packages used to initiate public safety calls for service, dispatch, and maintain the status of responding resources in the field. It is generally used by emergency communications dispatchers, call-takers, and 911 operators in centralized, public-safety call centers, as well as by field personnel utilizing mobile data terminals (MDTs) or mobile data computers (MDCs).
CAD systems consist of several modules that provide services at multiple levels in a dispatch center and in the field of public safety. These services include call input, call dispatching, call status maintenance, event notes, field unit status and tracking, and call resolution and disposition. CAD systems also include interfaces that permit the software to provide services to dispatchers, call takers, and field personnel with respect to control and use of analog radio and telephone equipment, as well as logger-recorder functions.
Methodology
Computer-assisted dispatch systems use one or more servers located in a central dispatch office, which communicate with computer terminals in a communications center or with mobile data terminals installed in vehicles. There are a multitude of CAD programs that suit different department needs, but the fundamentals of each system are the same. They include:
Log on/off times of police personnel (sworn/non-sworn)
Generating and archiving incidents that begin with a phone call from a citizen or originate from personnel in the field
Assigning field personnel to incidents
Updating Incidents and logging those updates
Generating case numbers for incidents that require an investigation
Timestamping every action taken by the dispatcher at the terminal
In an ideal setting, a call is received by a call-taker and information about the call is inputted into the CAD template. Simply, location, reporting party and incident are the main fields that have to be populated by type-codes. For example, if there was a burglary in progress, the type-code |
https://en.wikipedia.org/wiki/Mobile%20data%20terminal | A mobile data terminal (MDT) or mobile digital computer (MDC) is a computerized device used in emergency services, public transport, taxicabs, package delivery, roadside assistance, and logistics, among other fields, to communicate with a central dispatcher. They are also used to display mapping and information relevant to the tasks and actions performed by the vehicle such as CAD drawings, diagrams and safety information.
Mobile data terminals feature a screen on which to view information and a keyboard or keypad for entering information, and may be connected to various peripheral devices. Standard peripherals include two-way radios and taximeters, both of which predate computer-aided dispatching. MDTs may be simple display and keypad units, intended to be connected to a separate black-box or AVL (see below) computer. While MDTs were originally thin clients, most have been replaced with fully functional PC hardware, known as MDCs (Mobile Digital Computers). While the MDC term is more correct, MDT is still widely used. Other common terms include MVC (Motor Vehicle Computer) and names of manufacturers such as iMobile or KDT.
Technology
In the earlier days of computer-aided dispatching (CAD), many MDT's were custom devices, used with specialized point to point radios, particularly in applications such as police dispatching. While applications like taxi and package delivery often still use custom designed terminals, the majority of CAD systems have switched to ruggedized laptops and Wide-Area Wireless IP communications, utilizing the Internet or private IP networks connected to and over it.
For industrial applications such as commercial trucking, GIS, agriculture, mobile asset management, and other industries, custom electronic hardware is still preferred. Custom terminals use I/O interfaces that connect directly to industry-specific equipment. They are usually environmentally hardened packages with power supply protection and robust memory file systems that greatly improve reliability and task efficiency. MDT solutions that are based on ruggedized consumer products or consumer available software will typically not have the life cycle duration expected in industrial applications, over 5 years.
Typical features
9 VDC to 36 VDC input power.
May be tablet convertible.
Serial ports to connect to a satellite or terrestrial radio transceiver.
Digital I/O to monitor external events.
Removable medial or I/O port of retrieving data or upgrading software.
Wide operating temperature of to or greater.
Water and dust resistance rated.
Drop tested and rated.
Sealed against dust and liquid.
Connections to industry specific equipment, such as J1708 data bus for commercial truck applications.
Display technology specific to viewing conditions for the intended industry (LCD, TFT LCD, Vacuum fluorescent display, CSTN).
Integrated uninterruptible power supply, which will ride through electrical brown-outs typical in vehicle installations.
802.11 trans |
https://en.wikipedia.org/wiki/Time%20complexity | In theoretical computer science, the time complexity is the computational complexity that describes the amount of computer time it takes to run an algorithm. Time complexity is commonly estimated by counting the number of elementary operations performed by the algorithm, supposing that each elementary operation takes a fixed amount of time to perform. Thus, the amount of time taken and the number of elementary operations performed by the algorithm are taken to be related by a constant factor.
Since an algorithm's running time may vary among different inputs of the same size, one commonly considers the worst-case time complexity, which is the maximum amount of time required for inputs of a given size. Less common, and usually specified explicitly, is the average-case complexity, which is the average of the time taken on inputs of a given size (this makes sense because there are only a finite number of possible inputs of a given size). In both cases, the time complexity is generally expressed as a function of the size of the input. Since this function is generally difficult to compute exactly, and the running time for small inputs is usually not consequential, one commonly focuses on the behavior of the complexity when the input size increases—that is, the asymptotic behavior of the complexity. Therefore, the time complexity is commonly expressed using big O notation, typically etc., where is the size in units of bits needed to represent the input.
Algorithmic complexities are classified according to the type of function appearing in the big O notation. For example, an algorithm with time complexity is a linear time algorithm and an algorithm with time complexity for some constant is a polynomial time algorithm.
Table of common time complexities
The following table summarizes some classes of commonly encountered time complexities. In the table, , i.e., polynomial in x.
Constant time
An algorithm is said to be constant time (also written as time) if the value of (the complexity of the algorithm) is bounded by a value that does not depend on the size of the input. For example, accessing any single element in an array takes constant time as only one operation has to be performed to locate it. In a similar manner, finding the minimal value in an array sorted in ascending order; it is the first element. However, finding the minimal value in an unordered array is not a constant time operation as scanning over each element in the array is needed in order to determine the minimal value. Hence it is a linear time operation, taking time. If the number of elements is known in advance and does not change, however, such an algorithm can still be said to run in constant time.
Despite the name "constant time", the running time does not have to be independent of the problem size, but an upper bound for the running time has to be independent of the problem size. For example, the task "exchange the values of and if necessary so that " is calle |
https://en.wikipedia.org/wiki/Menu%20%28computing%29 | In user interface design, a menu is a list of options presented to the user.
Navigation
A user chooses an option from a menu by using an input device. Some input methods require linear navigation: the user must move a cursor or otherwise pass from one menu item to another until reaching the selection. On a computer terminal, a reverse video bar may serve as the cursor.
Touch user interfaces and menus that accept codes to select menu options without navigation are two examples of non-linear interfaces.
Some of the input devices used in menu interfaces are touchscreens, keyboards, mice, remote controls, and microphones. In a voice-activated system, such as interactive voice response, a microphone sends a recording of the user's voice to a speech recognition system, which translates it to a command.
Types of menus
A computer using a command line interface may present a list of relevant commands with assigned short-cuts (digits, numbers or characters) on the screen. Entering the appropriate short-cut selects a menu item. A more sophisticated solution offers navigation using the cursor keys or the mouse (even in two dimensions; then the menu items appear or disappear similarly to the menus common in GUIs). The current selection is highlighted and can be activated by pressing the enter key.
A computer using a graphical user interface presents menus with a combination of text and symbols to represent choices. By clicking on one of the symbols or text, the operator is selecting the instruction that the symbol represents. A context menu is a menu in which the choices presented to the operator are automatically modified according to the current context in which the operator is working.
A common use of menus is to provide convenient access to various operations such as saving or opening a file, quitting a program, or manipulating data. Most widget toolkits provide some form of pull-down or pop-up menu. Pull-down menus are the type commonly used in menu bars (usually near the top of a window or screen), which are most often used for performing actions, whereas pop-up (or "fly-out") menus are more likely to be used for setting a value, and might appear anywhere in a window.
According to traditional human interface guidelines, menu names were always supposed to be verbs, such as "file", "edit" and so on. This has been largely ignored in subsequent user interface developments. A single-word verb however is sometimes unclear, and so as to allow for multiple word menu names, the idea of a vertical menu was invented, as seen in NeXTSTEP.
Menus are now also seen in consumer electronics, starting with TV sets and VCRs that gained on-screen displays in the early 1990s, and extending into computer monitors and DVD players. Menus allow the control of settings like tint, brightness, contrast, bass and treble, and other functions such as channel memory and closed captioning. Other electronics with text-only displays can also have menus, anything from bus |
https://en.wikipedia.org/wiki/Levenshtein%20distance | In information theory, linguistics, and computer science, the Levenshtein distance is a string metric for measuring the difference between two sequences. Informally, the Levenshtein distance between two words is the minimum number of single-character edits (insertions, deletions or substitutions) required to change one word into the other. It is named after the Soviet mathematician Vladimir Levenshtein, who considered this distance in 1965.
Levenshtein distance may also be referred to as edit distance, although that term may also denote a larger family of distance metrics known collectively as edit distance. It is closely related to pairwise string alignments.
Definition
The Levenshtein distance between two strings (of length and respectively) is given by where
where the of some string is a string of all but the first character of , and is the first character of . Either the notation or is used to refer the th character of the string , counting from 0, thus .
Note that the first element in the minimum corresponds to deletion (from to ), the second to insertion and the third to replacement.
This definition corresponds directly to the naive recursive implementation.
Example
For example, the Levenshtein distance between "kitten" and "sitting" is 3, since the following 3 edits change one into the other, and there is no way to do it with fewer than 3 edits:
kitten → sitten (substitution of "s" for "k"),
sitten → sittin (substitution of "i" for "e"),
sittin → sitting (insertion of "g" at the end).
Upper and lower bounds
The Levenshtein distance has several simple upper and lower bounds. These include:
It is at least the absolute value of the difference of the sizes of the two strings.
It is at most the length of the longer string.
It is zero if and only if the strings are equal.
If the strings have the same size, the Hamming distance is an upper bound on the Levenshtein distance. The Hamming distance is the number of positions at which the corresponding symbols in the two strings are different.
The Levenshtein distance between two strings is no greater than the sum of their Levenshtein distances from a third string (triangle inequality).
An example where the Levenshtein distance between two strings of the same length is strictly less than the Hamming distance is given by the pair "flaw" and "lawn". Here the Levenshtein distance equals 2 (delete "f" from the front; insert "n" at the end). The Hamming distance is 4.
Applications
In approximate string matching, the objective is to find matches for short strings in many longer texts, in situations where a small number of differences is to be expected. The short strings could come from a dictionary, for instance. Here, one of the strings is typically short, while the other is arbitrarily long. This has a wide range of applications, for instance, spell checkers, correction systems for optical character recognition, and software to assist natural-language translation based on |
https://en.wikipedia.org/wiki/Edit%20distance | In computational linguistics and computer science, edit distance is a string metric, i.e. a way of quantifying how dissimilar two strings (e.g., words) are to one another, that is measured by counting the minimum number of operations required to transform one string into the other. Edit distances find applications in natural language processing, where automatic spelling correction can determine candidate corrections for a misspelled word by selecting words from a dictionary that have a low distance to the word in question. In bioinformatics, it can be used to quantify the similarity of DNA sequences, which can be viewed as strings of the letters A, C, G and T.
Different definitions of an edit distance use different sets of string operations. Levenshtein distance operations are the removal, insertion, or substitution of a character in the string. Being the most common metric, the term Levenshtein distance is often used interchangeably with edit distance.
Types of edit distance
Different types of edit distance allow different sets of string operations. For instance:
The Levenshtein distance allows deletion, insertion and substitution.
The longest common subsequence (LCS) distance allows only insertion and deletion, not substitution.
The Hamming distance allows only substitution, hence, it only applies to strings of the same length.
The Damerau–Levenshtein distance allows insertion, deletion, substitution, and the transposition (swapping) of two adjacent characters.
The Jaro distance allows only transposition.
Some edit distances are defined as a parameterizable metric calculated with a specific set of allowed edit operations, and each operation is assigned a cost (possibly infinite). This is further generalized by DNA sequence alignment algorithms such as the Smith–Waterman algorithm, which make an operation's cost depend on where it is applied.
Formal definition and properties
Given two strings and on an alphabet (e.g. the set of ASCII characters, the set of bytes [0..255], etc.), the edit distance is the minimum-weight series of edit operations that transforms into . One of the simplest sets of edit operations is that defined by Levenshtein in 1966:
Insertion of a single symbol. If = , then inserting the symbol produces . This can also be denoted ε→, using ε to denote the empty string.
Deletion of a single symbol changes to (→ε).
Substitution of a single symbol for a symbol ≠ changes to (→).
In Levenshtein's original definition, each of these operations has unit cost (except that substitution of a character by itself has zero cost), so the Levenshtein distance is equal to the minimum number of operations required to transform to . A more general definition associates non-negative weight functions ins(), del() and sub(, ) with the operations.
Additional primitive operations have been suggested. Damerau–Levenshtein distance counts as a single edit a common mistake: transposition of two adjacent characters, formally ch |
https://en.wikipedia.org/wiki/Broadcast%20network | A terrestrial network (or broadcast network in the United States) is a group of radio stations, television stations, or other electronic media outlets, that form an agreement to air, or broadcast, content from a centralized source. For example, (U.S.), (Canada), the (UK), the (Australia), (Germany), (South Korea), and NHK (Japan) are TV networks that provide programming for local terrestrial television station affiliates to air using signals that can be picked up by the home television sets of local viewers. Networks generally, but not always, operate on a national scale; that is, they cover an entire country.
Streaming media, Internet radio, and webcasting are sometimes considered forms of broadcasting despite the lack of terrestrial stations; its practitioners may also be called "broadcasters" or even "broadcast networks".
American networks
AT&T's "WEAF Chain"
Following the introduction of radio broadcasting in the early 1920s, the American Telephone and Telegraph Company (AT&T) developed the first radio network, linking together individual stations with specially prepared long-distance telephone lines in what at the time was called a "chain". The key station was AT&T's WEAF (now WFAN) in New York City. The network featured a variety of regularly scheduled programs which included sponsorships (at the time not called advertising but "toll broadcasting").
From the beginning, AT&T planned to eventually expand nationwide, so that national companies would be able reach large portions of the nation with their brand names and slogans in an efficient manner. At first the network's expansion was slow. In 1924, the Eveready Hour was broadcast over 12 stations, primarily located in the U.S. Northeast. Eveready Hour was the first commercially sponsored variety show in the history of broadcasting. By 1925, AT&T had linked together 26 stations in its network.
AT&T eventually decided to concentrate on its most profitable business, telephones, and in 1926 sold its broadcasting interests to the Radio Corporation of America (RCA). RCA's purchase included an agreement to lease AT&T phone lines.
RCA's "WJZ Chain"
In 1922 the Radio Corporation of America (RCA) followed AT&T's network model lead, and formed a small competing network centered on its New York City station, WJZ (now WABC). However, conflict resulted as RCA had a limited ability to lease lines from AT&T, and often had to use telegraph lines to connect stations, which had inferior acoustical properties.
NBC
After acquiring WEAF and AT&T's network assets in 1926, RCA created the National Broadcasting Company (NBC) and reorganized the WEAF chain (with WGR, WTIC, WTAG, WEEI, WJAR, WZAN, WFI-WLIT, WCAE, WRC, WTAM, WSAI, WWJ, WGN, WOC, KSD, WDAF, WCCO) as the NBC Red network and the WJZ chain as the NBC Blue network (with WBZ, WBZA, KYW, KDKA). (One explanation for the color designations is that they reflected the red and blue push pins used on a map that AT&T originally used to designate the a |
https://en.wikipedia.org/wiki/Time%20series | In mathematics, a time series is a series of data points indexed (or listed or graphed) in time order. Most commonly, a time series is a sequence taken at successive equally spaced points in time. Thus it is a sequence of discrete-time data. Examples of time series are heights of ocean tides, counts of sunspots, and the daily closing value of the Dow Jones Industrial Average.
A time series is very frequently plotted via a run chart (which is a temporal line chart). Time series are used in statistics, signal processing, pattern recognition, econometrics, mathematical finance, weather forecasting, earthquake prediction, electroencephalography, control engineering, astronomy, communications engineering, and largely in any domain of applied science and engineering which involves temporal measurements.
Time series analysis comprises methods for analyzing time series data in order to extract meaningful statistics and other characteristics of the data. Time series forecasting is the use of a model to predict future values based on previously observed values. While regression analysis is often employed in such a way as to test relationships between one or more different time series, this type of analysis is not usually called "time series analysis", which refers in particular to relationships between different points in time within a single series.
Time series data have a natural temporal ordering. This makes time series analysis distinct from cross-sectional studies, in which there is no natural ordering of the observations (e.g. explaining people's wages by reference to their respective education levels, where the individuals' data could be entered in any order). Time series analysis is also distinct from spatial data analysis where the observations typically relate to geographical locations (e.g. accounting for house prices by the location as well as the intrinsic characteristics of the houses). A stochastic model for a time series will generally reflect the fact that observations close together in time will be more closely related than observations further apart. In addition, time series models will often make use of the natural one-way ordering of time so that values for a given period will be expressed as deriving in some way from past values, rather than from future values (see time reversibility).
Time series analysis can be applied to real-valued, continuous data, discrete numeric data, or discrete symbolic data (i.e. sequences of characters, such as letters and words in the English language).
Methods for analysis
Methods for time series analysis may be divided into two classes: frequency-domain methods and time-domain methods. The former include spectral analysis and wavelet analysis; the latter include auto-correlation and cross-correlation analysis. In the time domain, correlation and analysis can be made in a filter-like manner using scaled correlation, thereby mitigating the need to operate in the frequency domain.
Additionally, t |
https://en.wikipedia.org/wiki/Animal%20Planet | Animal Planet (stylized in all lowercase since 2018) is an American multinational pay television channel, and associated AnimalPlanet.com website content, owned by the Warner Bros. Discovery Networks unit of Warner Bros. Discovery. First established on June 1, 1996, the channel is primarily devoted to series and documentaries about wild animals and domestic pets.
The channel was originally a joint venture with BBC Worldwide, and primarily focused on nature documentaries surrounding wildlife, targeting a family audience. In 2008, Animal Planet rebranded with a more mature programming direction, with a greater emphasis on aggressive and predatory portrayals of animals, as well as an increase in reality series following personalities involved in animal-related occupations and investigations. Animal Planet rebranded again in October 2018, pivoting away from its more aggressive branding.
, approximately 91,603,000 households receive Animal Planet. Discovery has also established or licensed international versions of the channel in various regions.
History
Animal Planet was launched on June 1, 1996; it was created by Discovery Communications in cooperation with BBC Worldwide. On January 1, 1997, Animal Planet's distribution grew as a result of Advance Entertainment Corporation selling the satellite transponder slot belonging to the WWOR EMI Service (a national superstation feed of Secaucus, New Jersey/New York City's WWOR-TV, that was implemented following the 1989 passage of the Syndication Exclusivity Rights Rule by the Federal Communications Commission) to Discovery Communications, replacing the feed with Animal Planet outright.
In late 2005, as part of a multi-million dollar expansion, the National Aquarium in Baltimore opened an exhibit called "Animal Planet Australia: Wild Extreme". Animal Planet and the National Aquarium in Baltimore announced a multi-year partnership the year prior, which produced an original orientation film that gives Aquarium visitors background on the Australian area which inspired the new exhibit and a dedicated area inside the expansion where visitors can learn about Animal Planet's conservation efforts and other programming. The partnership also allowed the possibility of future productions of television programs about the National Aquarium in Baltimore's research and exhibits.
In 2006, BBC Worldwide sold its 20% interest in the flagship Animal Planet U.S. network back to Discovery Communications. The BBC maintained its 50% ownership in Animal Planet's European, Asian and Latin American channels, as well as a minority interest in Animal Planet Japan and Animal Planet Canada until November 15, 2010, when BBC Worldwide sold 50% interest in Animal Planet and Liv to Discovery Communications for $156 million. Animal Planet is additionally an associate member of the Caribbean Cable Cooperative.
During the late 2000s, Genius Products announced a U.S. distribution agreement involving Animal Planet and TLC. Jakks Pacific |
https://en.wikipedia.org/wiki/Telephone%20call | A telephone call or telephone conversation (or telcon), also known as a phone call or voice call (or simply a call), is a connection over a telephone network between the called party and the calling party. Telephone calls started in the late 19th century. As technology has improved, a majority of telephone calls are made over a cellular network through mobile phones or over the internet with Voice over IP. Telephone calls are typically used for real-time conversation between two or more parties, especially when the parties cannot meet in person.
First telephone call
The first telephone call was made on March 10, 1876, by Alexander Graham Bell. Bell demonstrated his ability to "talk with electricity" by transmitting a call to his assistant, Thomas Watson. The first words transmitted were "Mr Watson, come here. I want to see you."
This event has been called Bell's "greatest success", as it demonstrated the first successful use of the telephone. Although it was his greatest success, he refused to have a telephone in his own home because it was something he invented by mistake and saw it as a distraction from his main studies.
Information transmission
A telephone call may carry ordinary voice transmission using a telephone, data transmission when the calling party and called party are using modems, or facsimile transmission when they are using fax machines. The call may use land line, mobile phone, satellite phone or any combination thereof. When a telephone call has more than one called party it is referred to as a conference call. When two or more users of the network are sharing the same physical line, it is called a party line or Rural phone line.
If the caller's wireline phone is connected directly to the calling party, when the caller takes their telephone off-hook, the calling party's phone will ring. This is called a hot line or ringdown. Otherwise, the calling party is usually given a tone to indicate they should begin dialing the desired number. In some (now very rare) cases, if the calling party cannot dial calls directly, they will be connected to an operator who places the call for them.
Calls may be placed through a public network (such as the Public Switched Telephone Network) provided by a commercial telephone company or a private network called a PBX. In most cases a private network is connected to the public network in order to allow PBX users to dial the outside world. Incoming calls to a private network arrive at the PBX in two ways: either directly to a users phone using a DDI number or indirectly via a receptionist who will answer the call first and then manually put the caller through to the desired user on the PBX.
Most telephone calls through the PSTN are set up using ISUP signalling messages or one of its variants between telephone exchanges to establish the end to end connection. Calls through PBX networks are set up using QSIG, DPNSS or variants.
Costs
Some types of calls are not charged, such as local calls (and |
https://en.wikipedia.org/wiki/Copy-on-write | Copy-on-write (COW), sometimes referred to as implicit sharing or shadowing, is a resource-management technique used in computer programming to efficiently implement a "duplicate" or "copy" operation on modifiable resources. If a resource is duplicated but not modified, it is not necessary to create a new resource; the resource can be shared between the copy and the original. Modifications must still create a copy, hence the technique: the copy operation is deferred until the first write. By sharing resources in this way, it is possible to significantly reduce the resource consumption of unmodified copies, while adding a small overhead to resource-modifying operations.
In virtual memory management
Copy-on-write finds its main use in sharing the virtual memory of operating system processes, in the implementation of the fork system call. Typically, the process does not modify any memory and immediately executes a new process, replacing the address space entirely. Thus, it would be wasteful to copy all of the process's memory during a fork, and instead the copy-on-write technique is used.
Copy-on-write can be implemented efficiently using the page table by marking certain pages of memory as read-only and keeping a count of the number of references to the page. When data is written to these pages, the operating-system kernel intercepts the write attempt and allocates a new physical page, initialized with the copy-on-write data, although the allocation can be skipped if there is only one reference. The kernel then updates the page table with the new (writable) page, decrements the number of references, and performs the write. The new allocation ensures that a change in the memory of one process is not visible in another's.
The copy-on-write technique can be extended to support efficient memory allocation by having a page of physical memory filled with zeros. When the memory is allocated, all the pages returned refer to the page of zeros and are all marked copy-on-write. This way, physical memory is not allocated for the process until data is written, allowing processes to reserve more virtual memory than physical memory and use memory sparsely, at the risk of running out of virtual address space. The combined algorithm is similar to demand paging.
Copy-on-write pages are also used in the Linux kernel's same-page merging feature.
In software
COW is also used in library, application and system code.
Examples
The string class provided by the C++ standard library was specifically designed to allow copy-on-write implementations in the initial C++98 standard, but not in the newer C++11 standard:
std::string x("Hello");
std::string y = x; // x and y use the same buffer.
y += ", World!"; // Now y uses a different buffer; x still uses the same old buffer.
In the PHP programming language, all types except references are implemented as copy-on-write. For example, strings and arrays are passed by reference, but when modified, they are duplicated |
https://en.wikipedia.org/wiki/Implementation | Implementation is the realization of an application, execution of a plan, idea, model, design, specification, standard, algorithm, policy, or the administration or management of a process or objective.
Industry-specific definitions
Computer science
In computer science, an implementation is a realization of a technical specification or algorithm as a program, software component, or other computer system through computer programming and deployment. Many implementations may exist for a given specification or standard. For example, web browsers contain implementations of World Wide Web Consortium-recommended specifications, and software development tools contain implementations of programming languages.
A special case occurs in object-oriented programming, when a concrete class implements an interface; in this case the concrete class is an implementation of the interface and it includes methods which are implementations of those methods specified by the interface.
Information technology
In the information technology during industry, implementation refers to post-sales process of guiding a client from purchase to use of the software or hardware that was purchased. This includes requirements analysis, scope analysis, customizations, systems integrations, user policies, user training and delivery. These steps are often overseen by a project manager using project management methodologies. Software Implementations involve several professionals that are relatively new to the knowledge based economy such as business analysts, software implementation specialists, solutions architects, and project managers.
To implement a system successfully, many inter-related tasks need to be carried out in an appropriate sequence. Utilising a well-proven implementation methodology and enlisting professional advice can help but often it is the number of tasks, poor planning and inadequate resourcing that causes problems with an implementation project, rather than any of the tasks being particularly difficult. Similarly with the cultural issues it is often the lack of adequate consultation and two-way communication that inhibits achievement of the desired results.
Political science
In political science, implementation refers to the carrying out of public policy. Legislatures pass laws that are then carried out by public servants working in bureaucratic agencies. This process consists of rule-making, rule-administration and rule-adjudication. Factors impacting implementation include the legislative intent, the administrative capacity of the implementing bureaucracy, interest group activity and opposition, and presidential or executive support.
In international relations, implementation refers to a stage of international treaty-making. It represents the stage when international provisions are enacted domestically through legislation and regulation. The implementation stage is different from the ratification of an international treaty.
Social and health sciences
Im |
https://en.wikipedia.org/wiki/Wrapper | Wrapper generally refers to a type of packaging. It may also refer to:
Computing
Wrapper (data mining), a technique used in data mining
Wrapper function, a function whose main purpose is to call a second function
Wrapper library
Driver wrapper, software that functions as an adapter between an operating system and a driver
Wrapper pattern, where some computer programming code allows certain classes to work together that otherwise would not
Primitive wrapper class, a computer term referring to a Java class in object-oriented programming
TCP Wrapper, software used for filtering network access.
Service wrapper, software that enables other programs to be run as services or daemons
A digital container format containing both data and metadata
Other
Wrapper (clothing), a woman's garment which is worn over nightwear in North America, and a colorful garment widely worn in West Africa
Wrapper (philately), postal stationery which pays the delivery cost of a newspaper or a periodical
Wrapper, the outer leaf of tobacco used in cigar making
Newspaper wrapper
The dust jacket of a hardcover book
See also
Label (disambiguation)
Wrap (disambiguation)
Rapping |
https://en.wikipedia.org/wiki/IDN | IDN can refer to:
Internationalized domain names
Institut Industriel du Nord, the former name of École Centrale de Lille
Indonesia, the ISO 3-letter country code
International Data Number, in the context of an X.121 address
Identity driven networking
Integrated data network, the digital data network developed by Reuters and dedicated to financial markets
Integrated Delivery Network, a network of healthcare organizations, see IDS
Intradermal nevus, a type of skin mole
See also
I Don't Know (disambiguation) - sometimes abbreviated as "IDN" |
https://en.wikipedia.org/wiki/Moving%20average%20%28disambiguation%29 | A moving average is a calculation to analyze data points by creating a series of averages of different subsets of the full data set.
Moving average may also refer to:
Moving-average model, an approach for modeling univariate time series models
Moving average filter, a finite impulse response filter in digital signal processing
Convolution, a moving average in other mathematical contexts
See also
Trix (technical analysis), a triple moving average |
https://en.wikipedia.org/wiki/American%20Music%20Awards | The American Music Awards (AMAs) is an annual American music awards show, generally held in the fall, created by Dick Clark in 1973 for American Broadcasting Company, when the network's contract to air the Grammy Awards expired. It is produced by Dick Clark Productions. From 1973 to 2005, both the winners and the nominations were selected by members of the music industry, based on commercial performance, such as sales and airplay. Since 2006, winners have been determined by a poll of the public and fans, who can vote through the AMAs website.
Conception
The AMAs was created by Dick Clark in 1973 to compete with the Grammy Awards after the move of that year's show to Nashville, Tennessee led to CBS (which has broadcast all Grammy Award shows since then) picking up the Grammy telecasts after its first two in 1971 and 1972 were broadcast on ABC. In 2014, American network Telemundo acquired the rights to produce a Spanish-language version of the American Music Awards and launched the Latin American Music Awards in 2015.
From 1973 to 2005, both the winners and the nominations were selected by members of the music industry, based on commercial performance, such as sales and airplay. Since 2006, winners have been determined by a poll of the public and fans, who can vote through the AMAs website, while nominations have remained based on sales, airplay, now including activity on social networks, and video viewing. Before 2010, had nominations based only on sales and airplay and nominated every work, even if old. The Grammys have nominations based on vote of the Academy and only nominate a work from their eligibility period that changes often.
The award statuette is manufactured by New York firm Society Awards.
Hosts
The first hosts for the first telecast of the AMAs were Helen Reddy, Roger Miller, and Smokey Robinson. Helen Reddy not only hosted the show but also became the first female artist to win an AMA for Favorite Pop/Rock Female artist. For the first decade or so, the AMAs had multiple hosts, each representing a genre of music. For instance, Glen Campbell would host the country portion (Campbell, in fact, has co-hosted the AMAs more times than any other host or co-host), while other artists would co-host to represent their genre. In recent years, however, there has been one single host.
In 1991, Keenen Ivory Wayans became the first Hollywood actor to host the AMAs.
From its inception in 1973 through 2002, the AMAs were held in mid- to late-January, but were moved to November (usually the Sunday before Thanksgiving) beginning in 2003 so as not to further compete with other major awards shows (such as the Golden Globe Awards and the Academy Awards) and allows for ABC to have a well-rated awards show during November sweeps.
For the 2008 awards, Jimmy Kimmel hosted for the fourth consecutive year. In 2009–2012, there was no host for the first time in history. Instead, the AMAs followed the Grammys' lead in having various celebrities give intr |
https://en.wikipedia.org/wiki/Justice%20League%20%28TV%20series%29 | Justice League is an American animated television series which ran from November 17, 2001, to May 29, 2004, on Cartoon Network. The show was produced by Warner Bros. Animation. It is based on the Justice League of America and associated comic book characters published by DC Comics. It serves as a sequel to Batman: The Animated Series and Superman: The Animated Series, as well as a prequel to Batman Beyond and, is the seventh series of the DC Animated Universe. After two seasons, the series was rebranded as Justice League Unlimited, a successor series which aired for three seasons.
It was the first show on Cartoon Network to be produced by Warner Bros. Animation, and was the last Cartoon Network show to be greenlit by Betty Cohen.
Overview
Bruce Timm, who co-produced Batman: The Animated Series and Superman: The Animated Series in the 1990s, became producer on an animated series focusing on the Justice League. The roster consisted of Batman, Superman, Wonder Woman, Green Lantern (John Stewart), The Flash (Wally West), Martian Manhunter (J'onn J'onzz), and Hawkgirl.
According to audio commentary on the DVD release of Season 2, the second-season finale "Starcrossed" was expected to be the final episode of the series. However, in February 2004, Cartoon Network announced a follow-up series, Justice League Unlimited, which premiered on July 31, 2004, and featured a larger roster of characters.
It is the first series in the DC Animated Universe to fully use digital ink and paint, also the first to be produced in widescreen starting in Season 2.
Production
Kevin Conroy reprised his voice role as Batman from Batman: The Animated Series (1992–1995), The New Batman Adventures (1997–1999), and Batman Beyond (1999–2001). Batman's costume was redesigned, but this time, his costume was a combination of his last three costumes. The same costume from The New Batman Adventures is retained, but with the blue highlights from the Batman: The Animated Series costume and the long-ears from the Batman Beyond costume are added to the costume.
Tim Daly, who voiced Superman in Superman: The Animated Series (1996–2000), was initially involved, but he was unable to continue his role due to involvement with The Fugitive. He was replaced by George Newbern.
Alongside Kevin Conroy and George Newbern as Superman, joining the rest of the main cast is Susan Eisenberg as Wonder Woman, Maria Canals-Barrera as Hawkgirl, Phil Lamarr as John Stewart, Michael Rosenbaum as Wally West / The Flash and Carl Lumbly as J'onn J'onnz / Martian Manhunter.
Superman was initially redesigned to have a bit of a squint to his eyes as well as cheekbones that were meant to make him look older than he did in Superman The Animated Series. Fans did not like the older appearance and in the second season the squint, grey streak and cheekbones were removed, in essence reverting Superman to his earlier animated look. As an in-joke, Superman's season one facial designs are used for an older Jor-El in t |
https://en.wikipedia.org/wiki/IEEE%20802.20 | IEEE 802.20 or Mobile Broadband Wireless Access (MBWA) was a specification by the standard association of the Institute of Electrical and Electronics Engineers (IEEE) for mobile broadband networks. The main standard was published in 2008. MBWA is no longer being actively developed.
This wireless broadband technology is also known and promoted as iBurst (or HC-SDMA, High Capacity Spatial Division Multiple Access). It was originally developed by ArrayComm and optimizes the use of its bandwidth with the help of smart antennas. Kyocera is the manufacturer of iBurst devices.
Description
iBurst is a mobile broadband wireless access system that was first developed by ArrayComm, and announced with partner Sony in April 2000.
It was adopted as the High Capacity – Spatial Division Multiple Access (HC-SDMA) radio interface standard (ATIS-0700004-2005) by the Alliance for Telecommunications Industry Solutions (ATIS).
The standard was prepared by ATIS’ Wireless Technology and Systems Committee's Wireless Wideband Internet Access subcommittee and accepted as an American National Standard in 2005.
HC-SDMA was announced as considered by ISO TC204 WG16 for the continuous communications standards architecture, known as Communications, Air-interface, Long and Medium range (CALM), which ISO is developing for intelligent transport systems (ITS). ITS may include applications for public safety, network congestion management during traffic incidents, automatic toll booths, and more. An official liaison was established between WTSC and ISO TC204 WG16 for this in 2005.
The HC-SDMA interface provides wide-area broadband wireless data-connectivity for fixed, portable and mobile computing devices and appliances. The protocol is designed to be implemented with smart antenna array techniques (called MIMO for multiple-input multiple-output) to substantially improve the radio frequency (RF) coverage, capacity and performance for the system.
In January 2006, the IEEE 802.20 Mobile Broadband Wireless Access Working Group adopted a technology proposal that included the use of the HC-SDMA standard for the 625kHz Multi-Carrier time-division duplex (TDD) mode of the standard. One Canadian vendor operates at 1.8 GHz.
Technical description
The HC-SDMA interface operates on a similar premise as cellular phones, with hand-offs between HC-SDMA cells repeatedly providing the user with a seamless wireless Internet access even when moving at the speed of a car or train.
The standard's proposed benefits:
IP roaming & handoff (at more than 1 Mbit/s)
New MAC and PHY with IP and adaptive antennas
Optimized for full mobility up to vehicular speeds of 250 km/h
Operates in Licensed Bands (below 3.5 GHz)
Uses Packet Architecture
Low Latency
Some technical details were:
Bandwidths of 5, 10, and 20 MHz.
Peak data rates of 80 Mbit/s.
Spectral efficiency above 1 bit/sec/Hz using multiple input/multiple output technology (MIMO).
Layered frequency hopping allocates OFDM carriers to near, middle, |
https://en.wikipedia.org/wiki/Long%20Duration%20Exposure%20Facility | NASA's Long Duration Exposure Facility, or LDEF (pronounced "eldef"), was a cylindrical facility designed to provide long-term experimental data on the outer space environment and its effects on space systems, materials, operations and selected spores' survival. It was placed in low Earth orbit by in April 1984. The original plan called for the LDEF to be retrieved in March 1985, but after a series of delays it was eventually returned to Earth by in January 1990.
It successfully carried science and technology experiments for about 5.7 years that have revealed a broad and detailed collection of space environmental data. LDEF's 69 months in space provided scientific data on the long-term effects of space exposure on materials, components and systems that has benefited NASA spacecraft designers to this day.
History
Researchers identified the potential of the planned Space Shuttle to deliver a payload to space, leave it there for a long-term exposure to the harsh outer space environment, and retrieve it for analysis on a separate mission. The LDEF concept evolved from a spacecraft proposed by NASA's Langley Research Center in 1970 to study the meteoroid environment, the Meteoroid and Exposure Module (MEM). The project was approved in 1974 and LDEF was built at NASA's Langley Research Center.
LDEF was intended to be reused, and redeployed with new experiments, perhaps every 18 months. but after the unintended extension of mission 1 the structure itself was treated as an experiment and intensively studied before being placed into storage.
Launch and deployment
The STS-41-C crew of deployed LDEF on April 7, 1984, into a nearly circular orbit at an altitude of 257 nautical miles.
Design and structure
The LDEF structure shape was a 12 sided prism (to fit the shuttle orbiter payload bay), and made entirely from stainless steel. There were 5 or 6 experiments on each of the 12 long sides and a few more on the ends. It was designed to fly with one end facing earth and the other away from earth.
Attitude control of LDEF was achieved with gravity-gradient stabilization and inertial distribution to maintain three-axis stability in orbit. Therefore, propulsion or other attitude control systems were not required, making LDEF free of acceleration forces and contaminants from jet firings. There was also a magnetic/viscous damper to stop any initial oscillation after deployment.
It had two grapple fixtures. An FRGF and an active (rigidize sensing) grapple used to send an electronic signal to initiate the 19 experiments that had electrical systems. This activated the Experiment Initiate System (EIS) which sent 24 initiation signals to the 20 active experiments. There were six initiation indications which were visible to the deploying astronauts next to the active grapple fixture.
Engineers originally intended that the first mission would last about one year, and that several long-duration exposure missions would use the same frame. The exposure facility wa |
https://en.wikipedia.org/wiki/Clipper%20chip | The Clipper chip was a chipset that was developed and promoted by the United States National Security Agency (NSA) as an encryption device that secured "voice and data messages" with a built-in backdoor that was intended to "allow Federal, State, and local law enforcement officials the ability to decode intercepted voice and data transmissions." It was intended to be adopted by telecommunications companies for voice transmission. Introduced in 1993, it was entirely defunct by 1996.
Key escrow
The Clipper chip used a data encryption algorithm called Skipjack to transmit information and the Diffie–Hellman key exchange-algorithm to distribute the public keys between peers. Skipjack was invented by the National Security Agency of the U.S. Government; this algorithm was initially classified SECRET, which prevented it from being subjected to peer review from the encryption research community. The government did state that it used an 80-bit key, that the algorithm was symmetric, and that it was similar to the DES algorithm. The Skipjack algorithm was declassified and published by the NSA on June 24, 1998. The initial cost of the chips was said to be $16 (unprogrammed) or $26 (programmed), with its logic designed by Mykotronx, and fabricated by VLSI Technology, Inc.
At the heart of the concept was key escrow. In the factory, any new telephone or other device with a Clipper chip would be given a cryptographic key, that would then be provided to the government in escrow. If government agencies "established their authority" to listen to a communication, then the key would be given to those government agencies, who could then decrypt all data transmitted by that particular telephone. The newly formed Electronic Frontier Foundation preferred the term "key surrender" to emphasize what they alleged was really occurring.
Clinton Administration
The Clinton Administration argued that the Clipper chip was essential for law enforcement to keep up with the constantly progressing technology in the United States. While many believed that the device would act as an additional way for terrorists to receive information, the Clinton Administration said it would actually increase national security. They argued that because "terrorists would have to use it to communicate with outsiders — banks, suppliers, and contacts — the Government could listen in on those calls."
Other proponents
There were several advocates of the Clipper chip who argued that the technology was safe to implement and effective for its intended purpose of providing law enforcement with the ability to intercept communications when necessary and with a warrant to do so. Howard S. Dakoff, writing in the John Marshall Law Review, stated that the technology was secure and the legal rationale for its implementation was sound. Stewart Baker wrote an opinion piece in Wired magazine debunking a series of what he purported to be myths surrounding the technology.
Backlash
Organizations such as the Electron |
https://en.wikipedia.org/wiki/ISight | iSight is a brand name used by Apple Inc. to refer to cameras on various devices. The name was originally used for the external iSight webcam, which retailed for US$149, connected to a computer via a FireWire cable, and came with a set of mounts to place it atop any then current Apple display, laptop computer, all-in-one desktop computer, or flat surface.
Apple introduced iSight at the 2003 Worldwide Developers Conference, and It was intended to be used with iChat AV, Apple's video-conferencing client. iMovie (version 4 and later) could also be used to capture video from the device. In April 2005, Apple released a firmware update for the iSight to improve audio performance. As of October 13, 2008, the external iSight was no longer for sale in the Apple online store or in retail locations.
Meanwhile, Apple began using the term to refer to the camera built into Apple's iMac, MacBook, MacBook Air, and MacBook Pro computers, Thunderbolt Display, and Cinema Display. In November 2010, Apple began calling them "FaceTime cameras". However, the term was not retired, as the iPhone 4 and later, iPod Touch (fifth generation and later), iPad (third generation and later), iPad Mini, and iPad Pro all incorporate an “iSight” rear camera in addition to a front-facing “FaceTime” or “FaceTime HD” camera.
Design
The external iSight's ¼-inch color CCD sensor has 640×480-pixel VGA resolution, with a custom-designed three-part F/2.8 lens with two aspherical elements. It features autoexposure, autofocusing from 50 mm to infinity, and video capture at 30 frames per second in 24-bit color with a variety of shutter speeds. However, the iSight has an image delay of approximately 120 ms.
The iSight incorporates internal microphones with dual-element noise suppression. The actual camera only takes up one-quarter of the unit; the remaining space is primarily occupied by its two microphones and mounting socket.
The iSight camera weighs 2.3 ounces (63.8 grams). It uses a single FireWire 400 (IEEE 1394a) cable (included) for audio, video, and power.
Four camera mounts, a plastic tube carrying case, and a FireWire camera mount adapter are also included. The user can select the mounting bracket most appropriate for their monitor or other mounting surface. It is fully compatible with its native macOS, as well as partially compatible with the Microsoft Windows and Linux operating systems.
The iSight has a small green LED that illuminates when the camera is in use. It also has an iris that closes by twisting the front of the camera.
Built-in iSight
Although external and internal iSights have significant differences, Apple has used the "iSight" name to brand its built-in video camera found in their MacBook (includes Retina MacBook (2015-2019)), MacBook Air and MacBook Pro notebook computers, iMac desktop computers produced since late 2005 and the LED Cinema Display. While the external iSight is similar to the built-in iSight, the built-in iSight uses an internal USB 2.0 inter |
https://en.wikipedia.org/wiki/Mac%20OS%20X%20Jaguar | Mac OS X Jaguar (version 10.2) is the third major release of macOS, Apple's desktop and server operating system. It superseded Mac OS X 10.1 and preceded Mac OS X Panther. The operating system was released on August 23, 2002 either for single-computer installations, and in a "family pack", which allowed five installations on separate computers in one household. Jaguar was the first Mac OS X release to publicly use its code name in marketing and advertisements.
System requirements
Mac OS X Jaguar required a PowerPC G3 or G4 CPU and 128 MB of RAM. Special builds were released for the first PowerPC G5 systems released by Apple.
New and changed features
Jaguar introduced many new features to Mac OS X, which are still supported to this day, including MPEG-4 support in QuickTime, Address Book, and Inkwell for handwriting recognition. It also included the first release of Apple's Zeroconf implementation, Rendezvous (later renamed to Bonjour), which allows devices on the same network to automatically discover each other and offer available services, such as file sharing, shared scanners, and printers, to the user.
Mac OS X Jaguar Server 10.2.2 added journaling to HFS Plus, the native Macintosh file system, to add increased reliability and data recovery features. This was later added to the standard Mac OS X in version 10.3 Panther.
Jaguar saw the debut of Quartz Extreme, a technology used to composite graphics directly on the video card, without the use of software to composite windows. The technology allotted the task of drawing the 3D surface of windows to the video card, rather than to the CPU, to increase interface responsiveness and performance.
Universal Access was added to allow the Macintosh to be usable by disabled computer users.
The user interface of Jaguar was also amended to add search features to the Finder using the updated Sherlock 3.
Internally, Jaguar also added the Common Unix Printing System (also known as CUPS), a modular printing system for Unix-like operating systems, and improved support for Microsoft Windows networks using the open-source Samba as a server for the SMB remote file access protocol and a FreeBSD-derived virtual file system module as a client for SMB.
The famous Happy Mac that had greeted Mac users for almost 18 years during the Macintosh startup sequence was replaced with a large grey Apple logo with the introduction of Mac OS X Jaguar.
Marketing
Unlike Mac OS X 10.1, Jaguar was a paid upgrade, costing $129. In October 2002, Apple offered free copies of Jaguar to all U.S K-12 teachers as part of the "X For Teachers" program. Teachers who wanted to get a copy simply had to fill out a form and a packet containing Mac OS X installation discs and manuals was shipped to the school where they worked.
Jaguar marked the first Mac OS X release which publicly used its code name as both a marketing ploy and as an official reference to the operating system. To that effect, Apple replaced the packaging for Mac OS X |
https://en.wikipedia.org/wiki/Label%20%28Mac%20OS%29 | In Apple's Macintosh operating systems, labels are a type of seven distinct colored and named parameters of metadata that can be attributed to items (files, folders and disks) in the filesystem. Labels were introduced in Macintosh System 7, released in 1991, and they were an improvement of the ability to colorize items in earlier versions of the Finder. Labels remained a feature of the Macintosh operating system through the end of Mac OS 9 in late 2001, but they were omitted from Mac OS X versions 10.0 to 10.2, before being reintroduced in version 10.3 in 2003, though not without criticism. During the short time period when Mac OS X lacked labels, third-party software replicated the feature.
In classic Mac OS
In classic Mac OS versions 7 through 9, applying a label to an item causes the item's icon to be tinted in that color when using a color computer monitor (as opposed to the black-and-white monitors of early Macs), and labels can be used as a search and sorting criterion. There is a choice of seven colors because three bits are reserved for the label color: 001 through 111, and 000 for no label. The names of the colors can be changed to represent categories assigned to the label colors. Both label colors and names can be customized in the classic Mac OS systems; however, Mac OS 8 and 9 provided this functionality through the Labels tab in the Finder Preferences dialog, while System 7 provided a separate Labels control panel. Labels in Mac OS 9 and earlier, once customized, were specific to an individual install; booting into another install, be it on another Mac or different disk would show different colors and names unless set identically. A colorless label could be produced by changing a label's color to black or white.
In Mac OS X and later
Mac OS X versions 10.3 to 10.8 apply the label color to the background of item names, except when an item is selected in column view, which changes the item name to the standard highlight color except for a label-colored dot after the name. Beginning in OS X 10.9, the label-colored background of item names is replaced with a small label-colored dot, and becomes a kind of tag.
Relation to tags
The Mac operating system has allowed users to assign multiple arbitrary tags as extended file attributes to any item ever since OS X 10.9 was released in 2013. These tags coexist with the legacy label system for backward compatibility, so that multiple colored (or colorless) tags can be added to a single item, but only the last colored tag applied to an item will set the legacy label that will be seen when viewing the item in the older operating systems. Labeled items that were created in the older operating systems will superficially seem to be tagged in OS X 10.9 and later even though they are only labeled and lack the newer tag extended file attributes (until they are edited in the new system). Since label colors can be changed in classic Mac OS but are standardized and unchangeable in the newer operating sys |
https://en.wikipedia.org/wiki/Watershed%20%28broadcasting%29 | In broadcasting, the watershed is the time of day after which programming with content deemed suitable only for mature or adult audiences is permitted.
In the same way that a geological watershed divides two drainage basins, a broadcasting watershed serves as a dividing line in a schedule between family-oriented content, and content deemed suitable only for a more mature audience, such as programs containing objectionable content; this can include graphic violence, strong language, and sexual content, or strong references to those themes, even if they are not shown explicitly. The transition to more adult material must not be unduly abrupt and the strongest material should appear later in the evening.
In some countries, watersheds are enforced by broadcasting laws. Cultural differences around the world allow those watershed times to vary. For instance, in Australia, the watershed time is 19:30 (7:30 p.m.), and in Italy it is 22:30 (10:30 p.m.). In some countries, the schedule is divided into periods with progressively fewer restrictions. In addition, some countries are more lenient towards subscription television and radio or pay-per-view channels than towards free-to-air channels.
By country
Argentina
In Argentina, any programmes broadcast between 06:00 or 07:00 and 22:00 or 22:30 must be suitable for all ages. There are also three other ratings, SAM 13, SAM 16, and SAM 18, which may be broadcast only during the broadcast time that is not covered by any programme suitable for family viewing.
Starting in September 2010, it is compulsory for broadcasters to show the notices "Comienza el horario apto para todo público" () and "Finaliza el horario apto para todo público" () at 6:00 a.m. or 7:00 a.m. and 10:00 p.m. or 10:30 p.m. respectively. In addition, the notice "Atención: Contenido no apto para niños, niñas y adolescentes" () are shown before news broadcasts.
Australia
On Australian television, programmes are restricted to certain times based on their rating. Since December 2015, PG-rated programmes can be shown at any time of day, M-rated programmes from 19:30, and MA15+ programmes from 20:30. M-rated programmes can also be shown from 12:00 to 15:00 on school days.
Complications with Australian time zones allow that to vary slightly in some areas. For example, when daylight saving time is in effect in New South Wales, NSW-based stations broadcasting to the Gold Coast, Queensland, would effectively push the broadcast watersheds an hour earlier, as Queensland does not observe DST; however, complaints by Gold Coast residents have forced those stations to delay prime-time programming by one hour to compensate.
With the exception of subscription narrowcast channels, anything rated R18+ must not be shown on Australian television at any time, and must be edited to fit within MA15+ guidelines. Even on subscription narrowcast channels, the owner of the channel must ensure that its content is restricted to access by those with appropriate disabli |
https://en.wikipedia.org/wiki/Directive | Directive may refer to:
Directive (European Union), a legislative act of the European Union
Directive (programming), a computer language construct that specifies how a compiler should process input
"Directive" (poem), a poem by Robert Frost
Directive speech act, a particular kind of speech act which causes the hearer to take a particular action
Lative case, a grammatical case that indicates direction
See also
Direction (disambiguation) |
https://en.wikipedia.org/wiki/Akalabeth%3A%20World%20of%20Doom | Akalabeth: World of Doom () is a role-playing video game released in 1979 for the Apple II. It was published by California Pacific Computer Company in 1980. Richard Garriott designed the game as a hobbyist project, which is now recognized as one of the earliest known examples of a role-playing video game and as a predecessor of the Ultima series of games that started Garriott's career. Garriott is the sole author of the game, with the exception of title artwork by Keith Zabalaoui.
Gameplay
The game attempts to bring the gameplay of pen-and-paper role-playing games to the computer platform. The player receives quests from Lord British (Garriott's alter-ego and nickname since high school) to kill a succession of ten increasingly difficult monsters.
The majority of gameplay takes place in an underground dungeon, but there was also a simple above-ground world map and text descriptions to fill out the rest of the adventure. The player could visit the Adventure Shop to purchase food, weapons, a shield and a magic amulet; the player's statistics can also be viewed here.
The game used concepts that would later become standard in the Ultima series, including:
First-person gameplay in dungeons
Requiring food to survive
A top-down overhead world view
Hotkeys used for commands
The use of Elizabethan English
Development
The game was made by teenager Richard Garriott in Applesoft BASIC for the Apple II while he was attending high school in the Houston, Texas suburbs. Begun first as a school project during his junior year using the school's mainframe system DEC PDP-11, the game continually evolved over two years under the working title DND with the help of his friends and regular Dungeons & Dragons partners who acted as play-testers. Final development of the game began soon after his initial encounter with Apple computers in the summer of 1979, on an Apple II bought for him by his father and, later, on an Apple II Plus, but Garriott did not expect that the public would see his work.
Early versions of the game used an overhead view with ASCII characters representing items and monsters. However, after playing Escape, an early maze game for the Apple II, he instead decided to switch to a wire-frame, first-person view for the underground dungeon portions of the game, making it the first computer role-playing game with such graphics. The game asks the player to provide a "lucky number", which it uses as a random seed to procedurally generate the rest of the game, including dungeons and player stats; by using the same number the player can always return to a given world. The Ultima Collection version added savegame support while still using a similar random seed.
When the game reached version DND28B later that year (where "28B" refers to the revision), he demoed the gamenow renamed to Akalabethfor his boss, John Prosper Mayer, at a Webster-area ComputerLand, who suggested he sell the game in the store. Garriott consented and spent $200 to package and se |
https://en.wikipedia.org/wiki/GIS%20file%20format | A GIS file format is a standard for encoding geographical information into a computer file, as a specialized type of file format for use in geographic information systems (GIS) and other geospatial applications. Since the 1970s, dozens of formats have been created based on various data models for various purposes. They have been created by government mapping agencies (such as the USGS or National Geospatial-Intelligence Agency), GIS software vendors, standards bodies such as the Open Geospatial Consortium, informal user communities, and even individual developers.
History
The first GIS installations of the 1960s, such as the Canada Geographic Information System were based on bespoke software and stored data in bespoke file structures designed for the needs of the particular project. As more of these appeared, they could be compared to find best practices and common structures. When general-purpose GIS software was developed in the 1970s and early 1980s, including programs from academic labs such as the Harvard Laboratory for Computer Graphics and Spatial Analysis, government agencies (e.g., the Map Overlay and Statistical System (MOSS) developed by the U.S. Fish & Wildlife Service and Bureau of Land Management), and new GIS software companies such as Esri and Intergraph, each program was built around its own proprietary (and often secret) file format. Since each GIS installation was effectively isolated from all others, interchange between them was not a major consideration.
By the early 1990s, the proliferation of GIS worldwide, and an increasing need for sharing data, soon accelerated by the emergence of the World Wide Web and spatial data infrastructures, led to the need for interoperable data and standard formats. An early attempt at standardization was the U.S. Spatial Data Transfer Standard, released in 1994 and designed to encode the wide variety of federal government data. Although this particular format failed to garner widespread support, it led to other standardization efforts, especially the Open Geospatial Consortium (OGC), which has developed or adopted several vendor-neutral standards, some of which have been adopted by the International Standards Organization (ISO).
Another development in the 1990s was the public release of proprietary file formats by GIS software vendors, enabling them to be used by other software. The most notable example of this was the publication of the Esri Shapefile format, which by the late 1990s had become the most popular de facto standard for data sharing by the entire geospatial industry. When proprietary formats were not shared (for example, the ESRI ARC/INFO coverage), software developers frequently reverse-engineered them to enable import and export in other software, further facilitating data exchange. One result of this was the emergence of free and open-source software libraries, such as the Geospatial Data Abstraction Library (GDAL), which have greatly facilitated the integration of spatial d |
https://en.wikipedia.org/wiki/Geometric%20standard%20deviation | In probability theory and statistics, the geometric standard deviation (GSD) describes how spread out are a set of numbers whose preferred average is the geometric mean. For such data, it may be preferred to the more usual standard deviation. Note that unlike the usual arithmetic standard deviation, the geometric standard deviation is a multiplicative factor, and thus is dimensionless, rather than having the same dimension as the input values. Thus, the geometric standard deviation may be more appropriately called geometric SD factor. When using geometric SD factor in conjunction with geometric mean, it should be described as "the range from (the geometric mean divided by the geometric SD factor) to (the geometric mean multiplied by the geometric SD factor), and one cannot add/subtract "geometric SD factor" to/from geometric mean.
Definition
If the geometric mean of a set of numbers is denoted as then the geometric standard deviation is
Derivation
If the geometric mean is
then taking the natural logarithm of both sides results in
The logarithm of a product is a sum of logarithms (assuming is positive for all so
It can now be seen that is the arithmetic mean of the set therefore the arithmetic standard deviation of this same set should be
This simplifies to
Geometric standard score
The geometric version of the standard score is
If the geometric mean, standard deviation, and z-score of a datum are known, then the raw score can be reconstructed by
Relationship to log-normal distribution
The geometric standard deviation is used as a measure of log-normal dispersion analogously to the geometric mean. As the log-transform of a log-normal distribution results in a normal distribution, we see that the
geometric standard deviation is the exponentiated value of the standard deviation of the log-transformed values, i.e.
As such, the geometric mean and the geometric standard deviation of a sample of
data from a log-normally distributed population may be used to find the bounds of confidence intervals analogously to the way the arithmetic mean and standard deviation are used to bound confidence intervals for a normal distribution. See discussion in log-normal distribution for details.
References
External links
Non-Newtonian calculus website
Scale statistics
Non-Newtonian calculus |
https://en.wikipedia.org/wiki/Loki%20%28disambiguation%29 | Loki is the god of mischief in Norse mythology.
Loki may also refer to:
Computing
LOKI, a family of cryptographic block ciphers
Loki (C++), a C++ software library
Loki (computer), a proposed home computer
Loki Software, a software firm
Loki, an open source logging platform available through Grafana
Fictional characters
Loki (Marvel Comics), a character in Marvel Comics
Loki (Marvel Cinematic Universe), the character adapted for the media franchise, since 2011
Loki (TV series), a 2021 Marvel series
Loki (Dark Horse Comics), a character in The Mask comic book series and related media
Loki (Dogma), a character in the film Dogma
Loki (Stargate), a character in the TV series Stargate SG-1
A character in the light novel series Is It Wrong to Try to Pick Up Girls in a Dungeon? and its derived works
A character in the TV series Space Academy
A character in the TV series Total Drama Presents: The Ridonculous Race
A character in the anime Saint Seiya: Soul of Gold
A character in the video game Age of Mythology
A character in the video game series God of War, more commonly known as Atreus
A character in the video game Fire Emblem Heroes
A character in the video game Bayonetta 2
A character in the video game Ghosts 'n Goblins
A character in the video game Vigilante 8
People
Loki (rapper), stage name of Darren McGarvey
A pseudonym of British mathematician and biostatistician Karl Pearson
Loki Schmidt, the wife of German ex-Chancellor Helmut Schmidt
Other uses
Loki, Indonesia. a village on Seram Island
Loki? (album), a 1974 album by Arnaldo Baptista
Loki (video game), a 2007 video game
"Loki", a 2012 song by Icelandic Viking metal band Skálmöld from the album Börn Loka
Loki (rocket), an American sounding rocket, later developed into the Super Loki rocket
Loki, an isopod genus in the family Bopyridae
Loki Patera, a volcano on Jupiter's moon Io
Lokichogio (also called Loki), a town in northern Kenya
Mount Loki, a mountain in British Columbia
Debreceni VSC, an association football club nicknamed Loki
LoKI, a SANS (small angle neutron scattering) beamline at the European Spallation Source
See also
Loki7, the alias of Roger Charles Bell, a pipe-bomber and former educator from Prince Edward Island, Canada
Loki's Castle, a field of hydrothermal vents
Lokiarchaeota, a proposed phylum of Archaea named after Loki's Castle
Loci, the plural of locus
Low Ki or Brandon Silvestry a professional wrestler
The Mythical Detective Loki Ragnarok
Lokai, a half-white, half-black character in "Let That Be Your Last Battlefield", an episode of Star Trek |
https://en.wikipedia.org/wiki/Integer%20programming | An integer programming problem is a mathematical optimization or feasibility program in which some or all of the variables are restricted to be integers. In many settings the term refers to integer linear programming (ILP), in which the objective function and the constraints (other than the integer constraints) are linear.
Integer programming is NP-complete. In particular, the special case of 0–1 integer linear programming, in which unknowns are binary, and only the restrictions must be satisfied, is one of Karp's 21 NP-complete problems.
If some decision variables are not discrete, the problem is known as a mixed-integer programming problem.
Canonical and standard form for ILPs
In integer linear programming, the canonical form is distinct from the standard form. An integer linear program in canonical form is expressed thus (note that it is the vector which is to be decided):
and an ILP in standard form is expressed as
where are vectors and is a matrix. As with linear programs, ILPs not in standard form can be converted to standard form by eliminating inequalities, introducing slack variables () and replacing variables that are not sign-constrained with the difference of two sign-constrained variables.
Example
The plot on the right shows the following problem.
The feasible integer points are shown in red, and the red dashed lines indicate their convex hull, which is the smallest convex polyhedron that contains all of these points. The blue lines together with the coordinate axes define the polyhedron of the LP relaxation, which is given by the inequalities without the integrality constraint. The goal of the optimization is to move the black dashed line as far upward while still touching the polyhedron. The optimal solutions of the integer problem are the points and that both have an objective value of 2. The unique optimum of the relaxation is with objective value of 2.8. If the solution of the relaxation is rounded to the nearest integers, it is not feasible for the ILP.
Proof of NP-hardness
The following is a reduction from minimum vertex cover to integer programming that will serve as the proof of NP-hardness.
Let be an undirected graph. Define a linear program as follows:
Given that the constraints limit to either 0 or 1, any feasible solution to the integer program is a subset of vertices. The first constraint implies that at least one end point of every edge is included in this subset. Therefore, the solution describes a vertex cover. Additionally given some vertex cover C, can be set to 1 for any and to 0 for any thus giving us a feasible solution to the integer program. Thus we can conclude that if we minimize the sum of we have also found the minimum vertex cover.
Variants
Mixed-integer linear programming (MILP) involves problems in which only some of the variables, , are constrained to be integers, while other variables are allowed to be non-integers.
Zero–one linear programming (or binary integer programming |
https://en.wikipedia.org/wiki/Rebasing | In computing, rebasing is the process of modifying data based on one reference to another. It can be one of the following:
Shared libraries
Rebasing is the process of creating a shared library image in such a way that it is guaranteed to use virtual memory without conflicting with any other shared libraries loadable in the system.
IBM VM/370 discontinuous saved segments (DCSS) were an early example of this technique, though not called rebasing. The technique is used extensively on Win32 platforms to avoid the overhead of address relocation of system DLLs by the loader.
Some security extensions to Linux/x86 use rebasing to force the use of code addresses below 0x00ffffff in order to introduce a 0x00 byte into all code pointers; This eliminates a certain class of buffer overflow security problems related to improper checking of null-terminated strings, common in the C programming language.
Other uses
Rebasing is the act of moving changesets to a different branch when using a revision control system or in some systems, by synchronizing a branch with the originating branch by merging all new changes in the latter to the former. For example, Git and Darcs do this (but Darcs extends the concept and calls it "patch commutation").
The mechanism that the Microsoft Exchange or Outlook daylight saving time (DST) rebasing tool TZMOVE.EXE uses to recalculate and reschedule appointment dates that are affected by DST.
See also
Relocation (computing)
Position-independent code
Portable Executable (PE)
High memory area (HMA)
Dynamic dead code elimination
Further reading
Code: Errata:
Computer libraries |
https://en.wikipedia.org/wiki/IBM%20RPG%20II | RPG II is a very early and popular version of the IBM RPG programming language.
It was developed in the late 1960s and designed to work on the smallest IBM systems of the time such as the IBM 1130, IBM System/3, System/32, System/34, System/36. It was also available for the System/370, The Singer System 10, Sperry Univac 90/25, 90/30, 90/40, System 80, 1100 mainframe series and the Wang VS Series. ICL produced versions for its ICL 2903 system and for VME/K; and Burroughs Corporation produced an RPG II compiler with database extensions for its B1700 series of computers. Digital Equipment Corporation had their own implementation named VAX RPG II for VAX/VMS systems.
An enhanced version RPG III appeared in 1978.
It has a number of unusual features, including: an implied processing loop; and that it is a fixed-format programming language, so that programs are difficult to read without a special debugging template.
Features
RPG II is a fixed-format programming language, which means that code must be placed in exact column locations in order to generate correct results. There are eight different specification types, and separate coding forms are used to write each, and a special debugging template used as an aid to read program printouts.
Every RPG II program executes within an implied loop, the program cycle, which applies the program successively to every record of a file - this is documented via a "Logic Flow" diagram on the debugging template. Each record (individual punched card) would be compared to each line in the program, which would act upon the record, or not, based upon whether that line had an "indicator" turned "on" or "off" — from a set of logical variables numbered 01–99 for user-defined purposes, or other smaller sets based upon record, field, or report processing functions. Special variables such as UDATE, UYEAR, PAGE, and so forth, are filled when the program begins or when page overflow occurs, even though there is no explicit instruction for these activities. Total calculations and output are done at "total time," after the detail cycle when L1/LR has been set on by fixed logic.
The concept of RPG's program cycle fitted neatly with a cyclical machine that read cards, summarised their contents and prints a result, rather like a tabulating machine. The language was extended to handle other input and output devices and provides a fast and efficient method of programming.
Devices such as the workstation (WORKSTN), the keyboard (KEYBORD), or the console (CONSOLE) do not have a fixed number of records at the beginning of the job and therefore, in order to incorporate the fixed-logic RPG "Last Record" cycle, the LR indicator can be set on with a SETON instruction. LR cannot be set off.
RPG II did not evolve much from the 1977 implementation on the System/34 to 2000 when the Advanced/36 was discontinued from marketing. Changes that were made from the 1970s version included the IFEQ/IFNE/IFGT/IFGE/IFLT/IFLE and END grouping. Also |
https://en.wikipedia.org/wiki/Spin%20lock | Spin lock may refer to:
Spin lock, a part of artillery fuze mechanism which arms the munition upon firing
Spinlock, a concept in multithread programming |
https://en.wikipedia.org/wiki/OpenRISC | OpenRISC is a project to develop a series of open-source hardware based central processing units (CPUs) on established reduced instruction set computer (RISC) principles. It includes an instruction set architecture (ISA) using an open-source license. It is the original flagship project of the OpenCores community.
The first (and only) architectural description is for the OpenRISC 1000 ("OR1k"), describing a family of 32-bit and 64-bit processors with optional floating-point arithmetic and vector processing support.
The OpenRISC 1200 implementation of this specification was designed by Damjan Lampret in 2000, written in the Verilog hardware description language (HDL).
The later mor1kx implementation, which has some advantages compared to the OR 1200, was designed by Julius Baxter and is also written in Verilog.
Additionally software simulators exist, which implement the OR1k specification.
The hardware design was released under the GNU Lesser General Public License (LGPL), while the models and firmware were released under the GNU General Public License (GPL).
A reference system on a chip (SoC) implementation based on the OpenRISC 1200 was developed, named the OpenRISC Reference Platform System-on-Chip (ORPSoC). Several groups have demonstrated ORPSoC and other OR1200 based designs running on field-programmable gate arrays (FPGAs), and there have been several commercial derivatives produced.
Later SoC designs, also based on an OpenRisc 1000 CPU implementation, are minSoC, OpTiMSoC and MiSoC.
Instruction set
The instruction set is a reasonably simple traditional RISC architecture reminiscent of MIPS using a 3-operand load-store architecture, with 16 or 32 general-purpose registers and a fixed 32-bit instruction length. The instruction set is mostly identical between the 32- and 64-bit versions of the specification, the main difference being the register width (32 or 64 bits) and page table layout. The OpenRISC specification includes all features common to modern desktop and server processors: a supervisor mode and virtual memory system, optional read, write, and execute control for memory pages, and instructions for synchronizing and interrupt handling between multiple processors.
Another notable feature is a rich set of single instruction, multiple data (SIMD) instructions intended for digital signal processing.
Implementations
Most implementations are on field-programmable gate arrays (FPGAs) which give the possibility to iterate on the design at the cost of performance.
By 2018, the OpenRISC 1000 was considered stable, so ORSoC (owner of OpenCores) began a crowdfunding project to build a cost-efficient application-specific integrated circuit (ASIC) to get improved performance. ORSoC faced criticism for this from the community. The project did not reach the goal.
, no open-source ASIC had been produced.
Commercial implementations
Several commercial organizations have developed derivatives of the OpenRISC 1000 architecture, including th |
https://en.wikipedia.org/wiki/Urpmi | urpmi is a package management tool for installing, removing, updating and querying software packages of local or remote (networked) media. It wraps around the RPM Package Manager in the role of a smart package manager. It uses repositories and will resolve dependencies so that the user will not suffer from dependency hell that can happen when using RPM directly. It works with official sources from Mandriva or unofficial sources such as those from the Penguin Liberation Front. It has a graphical front-end: Rpmdrake.
It's made of 2 parts:
a low level C/perl bindings
a higher level perl code implementing the advanced algorithms
In addition to the now-defunct Mandriva Linux, it is also being used by:
Uruk GNU/Linux, a 100% free software system origin in Iraq, based on this package manager virtually for Uruk package manager simulator, and Linux-libre kernels and apt real package manager from Trisquel, also named after a city in Iraq
Mageia, a French fork of Mandriva Linux that for a time was the base for future Mandriva products but is now an independent community driven Linux distribution.
ROSA Linux, a Russian fork of Mandriva Linux that is the base for future OpenMandriva products.
History
urpmi was developed as an experiment by Pascal Rigaux (Pixel) to address RPM install limitations; it was further maintained by François Pons and different Mandriva employees. It is currently (2010-2021) maintained by Thierry Vignaud who was the maintainer of rpmdrake and one of the co-maintainers of the drakx installer and tools at Mandriva before he continued doing that job at Mageia.
Per Øyvind Karlsen maintained a fork of urpmi at Rosa Linux, backporting fixes and improvements from Thierry Vignaud work, but this is not the version that was used by Mandriva Business Server (which was based on Mageia). This fork died around 2013 (date of last commit).
Commands
Generic commands
Useful commands
See also
AppStream
PackageKit
References
External links
CPAN page for the low level C/perl bindings
CPAN page for the high level perl code
Free package management systems
Linux package management-related software
Mandriva Linux |
https://en.wikipedia.org/wiki/Computer%20accessibility | Computer accessibility (also known as accessible computing) refers to the accessibility of a computer system to all people, regardless of disability type or severity of impairment. The term accessibility is most often used in reference to specialized hardware or software, or a combination of both, designed to enable the use of a computer by a person with a disability or impairment. Computer accessibility often has direct positive effects on people with disabilities.
Accessibility features are meant to make the use of technology less challenging for those with disabilities. Common accessibility features include text-to-speech, closed-captioning, and keyboard shortcuts. More specific technologies that need additional hardware may be referred to as assistive technology.
There are many disabilities or impairments that can be a barrier to effective computer use. These impairments, which can be acquired from disease, trauma, or maybe congenital, include but are not limited to:
Cognitive impairments (head injury, autism, developmental disabilities) and learning disabilities, (such as dyslexia, dyscalculia, or ADHD).
Visual impairment, such as low-vision, complete or partial blindness, and color blindness.
Hearing-related disabilities (deafness), including deafness, being hard of hearing, or hyperacusis.
Motor or dexterity impairment such as paralysis, cerebral palsy, dyspraxia, carpal tunnel syndrome, and repetitive strain injury.
A topic closely linked to computer accessibility is web accessibility. Similar to computer accessibility, web accessibility is the practice of making the use of the World Wide Web easier for individuals with disabilities.
Accessibility is often abbreviated as the numeronym a11y, where the number 11 refers to the number of letters omitted. This parallels the abbreviations of internationalization and localization as i18n and l10n, respectively. Moreover, a11y is also listed on the USPTO Supplemental Register under Accessibility Now, Inc.
Assessment for assistive technology use
People wishing to overcome an impairment in order to use a computer comfortably and productively may require a "special needs assessment" by an assistive technology consultant (such as an occupational therapist, a rehabilitation engineering technologist, or an educational technologist) to help them identify and configure appropriate assistive technologies to meet individual needs. Even those who are unable to leave their own home or who live far from assessment providers may be assessed (and assisted) remotely using remote desktop software and a web cam. For example, the assessor logs on to the client's computer via a broadband Internet connection, observes the user's computer skills, and then remotely makes accessibility adjustments to the client's computer where necessary.
Accessibility options for specific impairments
Cognitive impairments and illiteracy
The biggest challenge in computer accessibility is to make resources accessible to peopl |
https://en.wikipedia.org/wiki/El%20Toboso | El Toboso is a town and municipality located in the Mancha Alta de Toledo comarca, province of Toledo, Castile-La Mancha, central Spain. According to the 2009 data, El Toboso has a total population of 2,219 inhabitants. The economy of the town is based on wine production and cattle, and sheep.
El Toboso is famous for appearing in the novel Don Quixote by the Spanish writer Miguel de Cervantes, as the town in which the fictional character Dulcinea lives. The town also appears in Graham Greene's tribute Monsignor Quixote, where the heroes are a priest (supposedly a descendant of Cervantes's character), and the recently deposed Communist mayor of the town in the post-Franco era.
Main sights
The Catholic church of San Antonio Abad, built in the 15th century.
The convent of Trinitarias Recoletas, from the 17th century.
The Cervantine Museum.
The Museum of Dulcinea
The lake of La Nava.
References
Toboso |
https://en.wikipedia.org/wiki/Minsk%20family%20of%20computers | Minsk family of mainframe computers was developed and produced in the Byelorussian SSR from 1959 to 1975.
Models
The MINSK-1 was a vacuum-tube digital computer that went into production in 1960.
The MINSK-2 was a solid-state digital computer that went into production in 1962.
The MINSK-22 was a modified version of Minsk-2 that went into production in 1965.
The MINSK-23 went into production in 1966.
The most advanced model was Minsk-32, developed in 1968. It supported COBOL, FORTRAN and ALGAMS (a version of ALGOL). This and earlier versions also used a machine-oriented language called AKI (AvtoKod "Inzhener", i.e., "Engineer's Autocode"). It stood somewhere between the native assembly language SSK (Sistema Simvolicheskogo Kodirovaniya, or "System of symbolic coding") and higher-level languages, like FORTRAN.
The word size was 31 bits for Minsk-1 and 37 bits for the other models.
At one point the Minsk-222 (an upgraded prototype based on the most popular model, Minsk-22) and Minsk-32 were considered as a potential base for a future unified line of mutually compatible mainframes — that would later become the ES EVM line, but despite being popular among users, good match between their tech and Soviet tech base and familiarity to both programmers and technicians lost to the proposal to copy the IBM/360 line of mainframes — the possibility to just copy all the software existing for it was deemed more important.
See also
Mark Nemenman
References
Further reading
(NB. Has info on the Minsk-32 character set.)
External links
Russian Virtual Computer Museum
Belarusian inventions
Soviet inventions
Mainframe computers
Science and technology in Belarus
Ministry of Radio Industry (USSR) computers |
https://en.wikipedia.org/wiki/Challenge%E2%80%93response%20authentication | In computer security, challenge–response authentication is a family of protocols in which one party presents a question ("challenge") and another party must provide a valid answer ("response") to be authenticated.
The simplest example of a challenge–response protocol is password authentication, where the challenge is asking for the password and the valid response is the correct password.
An adversary who can eavesdrop on a password authentication can then authenticate itself by reusing the intercepted password. One solution is to issue multiple passwords, each of them marked with an identifier. The verifier can then present an identifier, and the prover must respond with the correct password for that identifier. Assuming that the passwords are chosen independently, an adversary who intercepts one challenge–response message pair has no clues to help with a different challenge at a different time.
For example, when other communications security methods are unavailable, the U.S. military uses the AKAC-1553 TRIAD numeral cipher to authenticate and encrypt some communications. TRIAD includes a list of three-letter challenge codes, which the verifier is supposed to choose randomly from, and random three-letter responses to them. For added security, each set of codes is only valid for a particular time period which is ordinarily 24 hours.
A more interesting challenge–response technique works as follows. Say Bob is controlling access to some resource. Alice comes along seeking entry. Bob issues a challenge, perhaps "52w72y". Alice must respond with the one string of characters which "fits" the challenge Bob issued. The "fit" is determined by an algorithm agreed upon by Bob and Alice. (The correct response might be as simple as "63x83z", with the algorithm changing each character of the challenge using a Caesar cipher. In the real world, the algorithm would be much more complex.) Bob issues a different challenge each time, and thus knowing a previous correct response (even if it is not "hidden" by the means of communication used between Alice and Bob) is of no use.
Other non-cryptographic protocols
Challenge–response protocols are also used to assert things other than knowledge of a secret value. CAPTCHAs, for example, are a variant on the Turing test, meant to determine whether a viewer of a Web or mobile application is a real person. In early CAPTCHAs, the challenge sent to the viewer was a distorted image of some text, and the viewer responded by typing in that text. The distortion was designed to make automated optical character recognition (OCR) difficult and prevent a computer program from passing as a human. However, due to advances in OCR, CAPTCHAs are now more commonly based on object detection challenges.
Cryptographic techniques
Non-cryptographic authentication was generally adequate in the days before the Internet, when the user could be sure that the system asking for the password was really the system they were trying to access, and |
https://en.wikipedia.org/wiki/Errno.h | errno.h is a header file in the standard library of the C programming language. It defines macros for reporting and retrieving error conditions using the symbol errno (short for "error number").
errno acts like an integer variable. A value (the error number) is stored in errno by certain library functions when they detect errors. At program startup, the value stored is zero. Library functions store only values greater than zero. Any library function can alter the value stored before return, whether or not they detect errors. Most functions indicate that they detected an error by returning a special value, typically NULL for functions that return pointers, and -1 for functions that return integers. A few functions require the caller to preset errno to zero and test it afterwards to see if an error was detected.
The errno macro expands to an lvalue with type int, sometimes with the extern and/or volatile type specifiers depending upon the platform. Originally this was a static memory location, but macros are almost always used today to allow for multi-threading, so that each thread will see its own thread-local error number.
The header file also defines macros that expand to integer constants that represent the error codes. The C standard library only requires three to be defined:
EDOM
Results from a parameter outside a function's domain, e.g.
ERANGE
Results from a result outside a function's range, e.g. on systems with a 32-bit wide long
EILSEQ (Required since 1994 Amendment 1 to C89 standard)
Results from an illegal byte sequence, e.g. on systems that use UTF-8.
POSIX compliant operating systems like AIX, Linux or Solaris include many other error values, many of which are used much more often than the above ones, such as EACCES for when a file cannot be opened for reading. C++11 additionally defines many of the same values found within the POSIX specification.
Traditionally, the first page of Unix system manuals, named intro(2), lists all errno.h macros, but this is not the case with Linux, where these macros are instead listed in the errno(3).
An can be translated to a descriptive string using strerror (defined in string.h) or a BSD extension called . The translation can be printed directly to the standard error stream using perror (defined in stdio.h). As in many Unix-like systems is not thread-safe, a thread-safe version is used, but conflicting definitions from POSIX and GNU makes it even less portable than the table.
GLIBC macros
The GNU C library (GLIBC) provides the additional POSIX error values macros in the header file . These are the descriptions of the macros provided by strerror, excluding 41 and 58 as they are not in the POSIX standard:
EPERM (1)
Operation not permitted
ENOENT (2)
No such file or directory
ESRCH (3)
No such process
EINTR (4)
Interrupted system call
EIO (5)
Input/output error
ENXIO (6)
No such device or address
E2BIG (7)
Argument list too long
ENOEXEC (8)
Exec format error
EBADF (9)
Bad file descri |
https://en.wikipedia.org/wiki/Reiser4 | Reiser4 is a computer file system, successor to the ReiserFS file system, developed from scratch by Namesys and sponsored by DARPA as well as Linspire. Reiser4 was named after its former lead developer Hans Reiser. , the Reiser4 patch set is still being maintained, but according to Phoronix, it is unlikely to be merged into mainline Linux without corporate backing.
Features
Some of the goals of the Reiser4 file system are:
Atomicity (filesystem operations either complete, or they do not, and they do not corrupt due to partially occurring)
Different transaction models: journaling, write-anywhere (copy-on-write), hybrid transaction model
More efficient journaling through wandering logs
More efficient support of small files, in terms of disk space and speed through block suballocation
Liquid items (or virtual keys) – a special format of records in the storage tree, which completely resolves the problem of internal fragmentation
EOTTL (extents on the twig level) – fully balanced storage tree, meaning that all paths to objects are of equal length
Faster handling of directories with large numbers of files
Transparent compression: Lempel-Ziv-Oberhumer (LZO), zlib
Plugin infrastructure
Dynamically optimized disk-layout through allocate-on-flush (also called delayed allocation in XFS)
Delayed actions (tree balancing, compression, block allocation, local defragmentation)
R and D (Rare and Dense) caches, synchronized at commit time
Transactions support for user-defined integrity
Metadata and inline-data checksums
Mirrors and failover
Precise discard support with delayed issuing of discard requests for SSD devices
Some of the more advanced Reiser4 features (such as user-defined transactions) are also not available because of a lack of a VFS API for them.
At present Reiser4 lacks a few standard file system features, such as an online repacker (similar to the defragmentation utilities provided with other file systems). The creators of Reiser4 say they will implement these later, or sooner if someone pays them to do so.
Performance
Reiser4 uses B*-trees in conjunction with the dancing tree balancing approach, in which underpopulated nodes will not be merged until a flush to disk except under memory pressure or when a transaction completes. Such a system also allows Reiser4 to create files and directories without having to waste time and space through fixed blocks.
, synthetic benchmarks performed by Namesys in 2003 show that Reiser4 is 10 to 15 times faster than its most serious competitor ext3 working on files smaller than 1 KiB. Namesys's benchmarks suggest it is typically twice the performance of ext3 for general-purpose filesystem usage patterns. Other benchmarks from 2006 show results of Reiser4 being slower on many operations. Benchmarks conducted in 2013 with Linux Kernel version 3.10 show that Reiser4 is considerably faster in various tests compared to in-kernel filesystems ext4, btrfs and XFS.
Integration with Linux
Reiser4 has |
https://en.wikipedia.org/wiki/Apple%20displays | Apple Inc. sold a variety of LCD and CRT computer displays in the past. Apple paused production of their own standalone displays in 2016 and partnered with LG to design displays for Macs. In June 2019, the Pro Display XDR was introduced, however it was expensive and targeted for professionals. Nearly three years later, in March 2022, the Studio Display was launched as a consumer-targeted counterpart to the professional monitor. These two are currently the only Apple-branded displays available.
CRT displays
In the beginning (throughout the 1970s), Apple did not manufacture or sell displays of any kind, instead recommending users plug-into their television sets or (then) expensive third party monochrome monitors. However, in order to offer complete systems through its dealers, Apple began to offer various third party manufactured 12″ monochrome displays, re-badged as the Monitor II.
First generation
Apple's manufacture history of CRT displays began in 1980, starting with the Monitor /// that was introduced alongside and matched the Apple III business computer. It was a 12″ monochrome (green) screen that could display 80×24 text characters and any type of graphics, however it suffered from a very slow phosphor refresh that resulted in a "ghosting" video effect. So it could be shared with Apple II computers, a plastic stand was made available to accommodate the larger footprint of the display.
Three years later came the introduction of the Apple manufactured Monitor //, which as the name implies, was more suited in look and style for the Apple II line and at the same time added improvements in features and visual quality. In 1984 a miniature 9″ screen, called the Monitor IIc, was introduced for the Apple IIc computer to help complement its compact size. This display was also the first to use the brand new design language for Apple's products called Snow White, as well as being the first display not in a beige color, but rather a bright, creamy off-white. By early 1985 came the first color CRTs, starting with the Monitor 100, a digital RGB display for the Apple III and Apple IIe (with appropriate card), followed shortly by the 14″ ColorMonitor IIe (later renamed to AppleColor Composite Monitor IIe) and ColorMonitor IIc (later renamed to AppleColor Composite Monitor IIc), composite video displays for those respective models. All of these Apple displays support the maximum Apple II Double Hi-Res standard of 560×192.
In 1986 came the introduction of the AppleColor RGB Monitor, a 12″ analog RGB display designed specifically for the Apple IIGS computer. It supported a resolution of 640×400 interlaced (640×200 non-interlaced) and could be used by the Macintosh II, in a limited fashion, with the Apple High Resolution Display Video Card. Also introduced that year was the Apple Monochrome Monitor, which cosmetically was identical to the former model but was a black and white composite display suitable in external appearance for the Apple IIGS, Apple IIc |
https://en.wikipedia.org/wiki/Folding%40home | Folding@home (FAH or F@h) is a distributed computing project aimed to help scientists develop new therapeutics for a variety of diseases by the means of simulating protein dynamics. This includes the process of protein folding and the movements of proteins, and is reliant on simulations run on volunteers' personal computers. Folding@home is currently based at the University of Pennsylvania and led by Greg Bowman, a former student of Vijay Pande.
The project utilizes graphics processing units (GPUs), central processing units (CPUs), and ARM processors like those on the Raspberry Pi for distributed computing and scientific research. The project uses statistical simulation methodology that is a paradigm shift from traditional computing methods. As part of the client–server model network architecture, the volunteered machines each receive pieces of a simulation (work units), complete them, and return them to the project's database servers, where the units are compiled into an overall simulation. Volunteers can track their contributions on the Folding@home website, which makes volunteers' participation competitive and encourages long-term involvement.
Folding@home is one of the world's fastest computing systems. With heightened interest in the project as a result of the COVID-19 pandemic, the system achieved a speed of approximately 1.22 exaflops by late March 2020 and reached 2.43 exaflops by April 12, 2020, making it the world's first exaflop computing system. This level of performance from its large-scale computing network has allowed researchers to run computationally costly atomic-level simulations of protein folding thousands of times longer than formerly achieved. Since its launch on October 1, 2000, Folding@home was involved in the production of 226 scientific research papers. Results from the project's simulations agree well with experiments.
Background
Proteins are an essential component to many biological functions and participate in virtually all processes within biological cells. They often act as enzymes, performing biochemical reactions including cell signaling, molecular transportation, and cellular regulation. As structural elements, some proteins act as a type of skeleton for cells, and as antibodies, while other proteins participate in the immune system. Before a protein can take on these roles, it must fold into a functional three-dimensional structure, a process that often occurs spontaneously and is dependent on interactions within its amino acid sequence and interactions of the amino acids with their surroundings. Protein folding is driven by the search to find the most energetically favorable conformation of the protein, i.e., its native state. Thus, understanding protein folding is critical to understanding what a protein does and how it works, and is considered a holy grail of computational biology. Despite folding occurring within a crowded cellular environment, it typically proceeds smoothly. However, due to a protein' |
https://en.wikipedia.org/wiki/List%20of%20the%20largest%20municipalities%20in%20Canada%20by%20population | The table below lists the 100 largest census subdivisions (municipalities or municipal equivalents) in Canada by population, using data from the 2021 census for census subdivisions.
This list includes only the population within a census subdivision's boundaries as defined at the time of the census. Many census subdivisions are part of a larger census metropolitan area or census agglomeration. For their ranking, see the list of census metropolitan areas and agglomerations in Canada.
A city is displayed in bold if it is a provincial or federal capital (Ottawa), and in italics if it is the most populous city in the province. The three territories (Yukon, Northwest Territories, Nunavut) and one province (Prince Edward Island) do not have municipalities among the 100 most populous in Canada.
See also
List of the largest cities and towns in Canada by area
List of the largest population centres in Canada
List of largest Canadian cities by census
List of census metropolitan areas and agglomerations in Canada
Population of Canada by year
Population of Canada by province and territory
References
Demographics of Canada
Canada municipalities
Municipalities |
https://en.wikipedia.org/wiki/List%20of%20census%20metropolitan%20areas%20and%20agglomerations%20in%20Canada | This is a list of the census metropolitan areas and agglomerations in Canada by population, using data from the 2021 Canadian census and the 2016 Canadian census. Each entry is identified as a census metropolitan area (CMA) or a census agglomeration (CA) as defined by Statistics Canada.
A city's metropolitan area in colloquial or administrative terms may be different from its CMA as defined by Statistics Canada, resulting in differing populations. Such is the case with the Greater Toronto Area, where its metro population is notably higher than its CMA population due to its inclusion of the neighbouring Oshawa CMA to the east and the Burlington portion of the neighbouring Hamilton CMA to the west.
In 2021, 27,465,137 people (71.9% of Canada's population) lived in a CMA, while 4,596,279 (12.0%) lived in a CA.
Recent growth
Between 2016 and 2021, the five CMAs with the highest percentage growth were located in British Columbia and Southern Ontario. The five CMAs with the lowest percentage growth were in Quebec, Alberta, Northern Ontario and Newfoundland and Labrador. There were no CMAs for which negative growth was recorded in the 2021 census. The five CAs that grew the fastest were in British Columbia, Southern Ontario, and Alberta, while the five CAs whose population declined the most were in New Brunswick, Saskatchewan, Northern British Columbia, Manitoba and Newfoundland and Labrador.
Between 2011 and 2016, the six fastest-growing CMAs by percentage growth were located in Western Canada, with Alberta's two CMAs, Calgary and Edmonton, leading the country. Saskatoon, Regina, and Lethbridge rounded out the top five in the country and each grew by at least 10%. Of the remaining 30 CMAs, population growth was recorded in all but two of them. Those that experienced population decline were Brantford and Saint John. Ten of the fifteen fastest-growing CAs in Canada between the two most recent censuses were located in Alberta. The other five were located in British Columbia with two, and Manitoba, Ontario and Yukon each with one.
Between 2006 and 2011, twenty-four CAs experienced population decline. The fifteen CAs that experienced the greatest population decline were located in British Columbia (two), Manitoba (one), New Brunswick (one), Nova Scotia (three), Ontario (four) and Quebec (four). Okotoks experienced the greatest increase while Thompson experienced the greatest decline.
List
Canada had 41 CMAs and 111 CAs at the 2021 census. The number of CMAs increased from 35 in 2016 with the promotion of the Nanaimo, Kamloops, Chilliwack, Fredericton, Drummondville and Red Deer CAs. Overall, between promotion to CMA, absorption, and dissolution, the number of CAs decreased by seven. Amos was reinstated as a CA and Ladysmith, Trail and Essa were added as new CAs. The Carleton Place and Arnprior CAs were dissolved as they were added to the Ottawa–Gatineau CMA, the Leamington CA was dissolved as it was added to the Windsor CMA, and the Cold Lake and |
https://en.wikipedia.org/wiki/Thunder%20Force%20%28video%20game%29 | is a free-roaming scrolling shooter computer game released by Technosoft in 1983. It is the first game in the Thunder Force series. It was initially released for the X1 computer, and later appeared on the Sharp MZ-1500, PC-6001 mkII, and in 1985 on the PC-8801 mkII. In 1984, it was released for the FM-7 and PC-9801 computers as Thunder Force Construction, featuring an add-on that allowed players to create custom made areas, like a level editor or game creation system.
Gameplay
The structure of the game consists of overhead, free-directional scrolling areas and the player's ship is armed with main shot to shoot airborne targets and a bomb shot to shoot ground enemies. Gameplay consists of flying the FIRE LEO over ORN occupied areas while destroying enemy base installations and turrets. Each area has a certain number of shield generators hidden under the ground-based, enemy targets; in order for an area to be completed, the shield generators must be found and destroyed. After doing so, the Dyradeizer will temporally appear and the player must destroy a certain section of it. Once this section is destroyed, the Dyradeizer will disappear and the player will be taken to the next area to repeat the process.
Plot
The ORN Empire (antagonists of the game) has built a large asteroid fortress named the Dyradeizer to oppose the Galaxy Federation. In addition to its high firepower capabilities, Dyradeizer is supported by shield generators hidden in various locations by ORN, which render the fortress invisible. In an attempt to destroy Dyradeizer, the Galaxy Federation sends their specially designed fighter, the FIRE LEO (controlled by the player), to locate and destroy the shield generators and defeat Dyradeizer.
Development
The original Thunder Force was created by Kotori Yoshimura in 1983. She later left Technosoft and founded Arsys Software in 1985. In 1984, Technosoft released a level editor, or game creation system, entitled Thunder Force Construction, created by Yoshimura for the FM-7 computer.
Legacy
The success of the game led to a number of sequels in the Thunder Force series.
References
External links
Forgotten Franchises: Thunder Force (from Sega-16) - In depth article about the Thunder Force games. Also contains some media (the Thunder Force VI video mentioned above can be found here).
ThunderForce Forever - Contains artwork/renderings, fanfiction, story information related to Thunder Force. It is also the homepage of Thunder Future, a fan made Thunder Force game currently in development, and contains information about its progress.
Thunderforce Cafe - Fanlisting dedicated to Thunder Force. Contains artwork, music, video, merchandise pictures, etc.
1983 video games
FM-7 games
Japan-exclusive video games
NEC PC-6001 games
NEC PC-8801 games
NEC PC-9801 games
Sharp MZ games
Sharp X1 games
Technosoft games
Thunder Force
Video games developed in Japan |
https://en.wikipedia.org/wiki/Internet%20Printing%20Protocol | The Internet Printing Protocol (IPP) is a specialized communication protocol for communication between client devices (computers, mobile phones, tablets, etc.) and printers (or print servers). It allows clients to submit one or more print jobs to the network-attached printer or print server, and perform tasks such as querying the status of a printer, obtaining the status of print jobs, or cancelling individual print jobs.
Like all IP-based protocols, IPP can run locally or over the Internet. Unlike other printing protocols, IPP also supports access control, authentication, and encryption, making it a much more capable and secure printing mechanism than older ones.
IPP is the basis of several printer logo certification programs including AirPrint, IPP Everywhere, and Mopria Alliance, and is supported by over 98% of printers sold today.
History
IPP began as a proposal by Novell for the creation of an Internet printing protocol project in 1996. The result was a draft written by Novell and Xerox called the Lightweight Document Printing Application (LDPA), derived from ECMA-140: Document Printing Application (DPA). At about the same time, Lexmark publicly proposed something called the HyperText Printing Protocol (HTPP), and both HP and Microsoft had started work on new print services for what became Windows 2000. Each of the companies chose to start a common Internet Printing Protocol project in the Printer Working Group (PWG) and negotiated an IPP birds-of-a-feather (or BOF) session with the Application Area Directors in the Internet Engineering Task Force (IETF). The BOF session in December 1996 showed sufficient interest in developing a printing protocol, leading to the creation of the IETF Internet Printing Protocol (ipp) working group, which concluded in 2005.
Work on IPP continues in the PWG Internet Printing Protocol workgroup with the publication of 23 candidate standards, 1 new and 3 updated IETF RFCs, and several registration and best practice documents providing extensions to IPP and support for different services including 3D Printing, scanning, facsimile, cloud-based services, and overall system and resource management.
IPP/1.0 was published as a series of experimental documents (RFC 2565, RFC 2566, RFC 2567, RFC 2568, RFC 2569, and RFC 2639) in 1999.
IPP/1.1 followed as a draft standard in 2000 with support documents in 2001, 2003, and 2015 (RFC 2910, RFC 2911, RFC 3196, RFC 3510 RFC 7472). IPP/1.1 was updated as a proposed standard in January 2017 (RFC 8010, RFC 8011,) and then adopted as Internet Standard 92 (STD 92,) in June 2018.
IPP 2.0 was published as a PWG Candidate Standard in 2009 (PWG 5100.10-2009,) and defined two new IPP versions (2.0 for printers and 2.1 for print servers) with additional conformance requirements beyond IPP 1.1. A subsequent Candidate Standard replaced it in 2011 defining an additional 2.2 version for production printers (PWG 5100.12-2011,). This specification was updated and approved as a full PWG |
https://en.wikipedia.org/wiki/CUPS | CUPS (formerly an acronym for Common UNIX Printing System) is a modular printing system for Unix-like computer operating systems which allows a computer to act as a print server. A computer running CUPS is a host that can accept print jobs from client computers, process them, and send them to the appropriate printer.
CUPS consists of a print spooler and scheduler, a filter system that converts the print data to a format that the printer will understand, and a backend system that sends this data to the print device. CUPS uses the Internet Printing Protocol (IPP) as the basis for managing print jobs and queues. It also provides the traditional command line interfaces for the System V and Berkeley print systems, and provides support for the Berkeley print system's Line Printer Daemon protocol and limited support for the Server Message Block (SMB) protocol. System administrators can configure the device drivers which CUPS supplies by editing text files in Adobe's PostScript Printer Description (PPD) format. There are a number of user interfaces for different platforms that can configure CUPS, and it has a built-in web-based interface. CUPS is free software, provided under the Apache License.
History
Michael Sweet, who owned Easy Software Products, started developing CUPS in 1997 and the first public betas appeared in 1999. The original design of CUPS used the Line Printer Daemon protocol (LPD), but due to limitations in LPD and vendor incompatibilities, the Internet Printing Protocol (IPP) was chosen instead. CUPS was initially called "The Common UNIX Printing System". This name was shortened to just "CUPS" beginning with CUPS 1.4 due to legal concerns with the UNIX trademark. CUPS was quickly adopted as the default printing system for most Linux distributions. In March 2002, Apple Inc. adopted CUPS as the printing system for Mac OS X 10.2. In February 2007, Apple Inc. hired chief developer Michael Sweet and purchased the CUPS source code. On December 20, 2019, Michael Sweet announced on his blog that he had left Apple. In 2020, the OpenPrinting organization forked the project, with Michael Sweet continuing work on it.
Overview
CUPS provides a mechanism that allows print jobs to be sent to printers in a standard fashion. The print data goes to a scheduler which sends jobs to a filter system that converts the print job into a format the printer will understand. The filter system then passes the data on to a backend—a special filter that sends print data to a device or network connection. The system makes extensive use of PostScript and rasterization of data to convert the data into a format suitable for the destination printer.
CUPS offers a standard and modularised printing system that can process numerous data formats on the print server. Before CUPS, it was difficult to find a standard printer management system that would accommodate the very wide variety of printers on the market using their own printer languages and formats. For instance, |
https://en.wikipedia.org/wiki/Radio%20comedy | Radio comedy, or comedic radio programming, is a radio broadcast that may involve variety show, sitcom elements, sketches, and various types of comedy found in other media. It may also include more surreal or fantastic elements, as these can be conveyed on a small budget with just a few sound effects or some simple dialogue. Radio comedy began in the United States in 1930, based on the fact that as most United Kingdom music hall comedians such as Charlie Chaplin and Stan Laurel progressed to silent films, they moved to Hollywood and fed the radio comedy field. Another British music hall comic, George Formby, stayed in the British movie industry, and in 1940 joined the Entertainments National Service Association to entertain British World War II troops. UK radio comedy therefore started later, in the 1950s.
Background and history
Radio comedy began in the United States in 1930, and got a much later start in the United Kingdom because many of the British comedians (such as Charlie Chaplin and Stan Laurel) emigrated to the U.S. to make silent movies in Hollywood, and the American comedians who did not become dramatic actors migrated to radio. Raymond Knight launched The Cuckoo Hour on NBC in 1930, along with the 1931 network debut of Stoopnagle and Budd on CBS. Comedians such as Fred Allen, Jack Benny, Judy Canova, Bob Hope and Red Skelton were top-rated in the decades that followed. Even after the big name comedians moved to television in the 1950s, radio comedy continued, notably from Bob and Ray (1946–1988), The Firesign Theatre (1966–1972), and segments heard on NBC's Monitor (1955–1975).
Radio comedy did not begin in the United Kingdom until a generation later, with such popular 1950s shows as The Goon Show (started 1951) and Hancock's Half Hour (started 1957). Later, radio became a proving-ground for many later United Kingdom comedians. Chris Morris began his career in 1986 at Radio Cambridgeshire, and Ricky Gervais began his comedy career in 1997 at London radio station XFM.
Although traditional comedy was once a significant part of American broadcast radio programming, it is now mainly found in the archives of Old Time Radio enthusiasts and on the Internet streaming of comedy recordings. The majority of mainstream radio comedy now consists of personality-driven shows hosted by talk-radio hosts such as Howard Stern or comedic duos such as Armstrong & Getty and Bob & Tom. Exceptions to this are WSRN's "Audience of Two", Garrison Keillor's work on Minnesota Public Radio: A Prairie Home Companion and Comedy College, and NPR's Car Talk, a comedy show thinly disguised as car advice, and Wait Wait... Don't Tell Me!. Shows featuring comedic music are also popular; one of the better known national comedy music programs is the long-running weekly program hosted by Dr. Demento, and several other local stations (mostly college radio, freeform and eclectic formats) have similar programs. Several networks program 24 hours a day of stand-up comedy rout |
https://en.wikipedia.org/wiki/Bluefield | Bluefield may refer to:
Bluefield, Virginia, US
Bluefield, West Virginia, US
Nvidia BlueField, a line of computer hardware
See also
Bluefields, Nicaragua
Bluefields, Jamaica |
https://en.wikipedia.org/wiki/Booklet | Booklet may refer to:
A small book or group of pages
A pamphlet
A type of tablet computer
Postage stamp booklet, made up of one or more small panes of postage stamps in a cardboard cover
Liner notes, writings found in booklets which come inserted into the compact disc or DVD jewel case or the equivalent packaging for vinyl records and cassettes
Digital booklet, the digital equivalent of liner notes that often accompany digital music purchases
Nokia Booklet 3G, a netbook computer
Programme (booklet), available for patrons attending live events
See also
Book (disambiguation) |
https://en.wikipedia.org/wiki/Classic%20RISC%20pipeline | In the history of computer hardware, some early reduced instruction set computer central processing units (RISC CPUs) used a very similar architectural solution, now called a classic RISC pipeline. Those CPUs were: MIPS, SPARC, Motorola 88000, and later the notional CPU DLX invented for education.
Each of these classic scalar RISC designs fetches and tries to execute one instruction per cycle. The main common concept of each design is a five-stage execution instruction pipeline. During operation, each pipeline stage works on one instruction at a time. Each of these stages consists of a set of flip-flops to hold state, and combinational logic that operates on the outputs of those flip-flops.
The classic five stage RISC pipeline
Instruction fetch
The instructions reside in memory that takes one cycle to read. This memory can be dedicated to SRAM, or an Instruction Cache. The term "latency" is used in computer science often and means the time from when an operation starts until it completes. Thus, instruction fetch has a latency of one clock cycle (if using single-cycle SRAM or if the instruction was in the cache). Thus, during the Instruction Fetch stage, a 32-bit instruction is fetched from the instruction memory.
The Program Counter, or PC is a register that holds the address that is presented to the instruction memory. The address is presented to instruction memory at the start of a cycle. Then during the cycle, the instruction is read out of instruction memory, and at the same time, a calculation is done to determine the next PC. The next PC is calculated by incrementing the PC by 4, and by choosing whether to take that as the next PC or to take the result of a branch/jump calculation as the next PC. Note that in classic RISC, all instructions have the same length. (This is one thing that separates RISC from CISC ). In the original RISC designs, the size of an instruction is 4 bytes, so always add 4 to the instruction address, but don't use PC + 4 for the case of a taken branch, jump, or exception (see delayed branches, below). (Note that some modern machines use more complicated algorithms (branch prediction and branch target prediction) to guess the next instruction address.)
Instruction decode
Another thing that separates the first RISC machines from earlier CISC machines, is that RISC has no microcode. In the case of CISC micro-coded instructions, once fetched from the instruction cache, the instruction bits are shifted down the pipeline, where simple combinational logic in each pipeline stage produces control signals for the datapath directly from the instruction bits. In those CISC designs, very little decoding is done in the stage traditionally called the decode stage. A consequence of this lack of decoding is that more instruction bits have to be used to specifying what the instruction does. That leaves fewer bits for things like register indices.
All MIPS, SPARC, and DLX instructions have at most two register inpu |
https://en.wikipedia.org/wiki/Tmpfs | tmpfs (short for Temporary File System) is a temporary file storage paradigm implemented in many Unix-like operating systems. It is intended to appear as a mounted file system, but data is stored in volatile memory instead of a persistent storage device. A similar construction is a RAM disk, which appears as a virtual disk drive and hosts a disk file system.
Semantics
Everything stored in tmpfs is temporary in the sense that no files will be directly created on non-volatile storage such as a hard drive (although swap space is used as backing store according to the page replacement policy of the operating system). On reboot, everything in tmpfs will be lost.
The memory used by tmpfs grows and shrinks to accommodate the files it contains.
Many Unix distributions enable and use tmpfs by default for the branch of the file system or for shared memory. This can be observed with as in this example:
Filesystem Size Used Avail Use% Mounted on
tmpfs 256M 688K 256M 1% /tmp
Some Linux distributions (e.g. Debian) do not have a tmpfs mounted on by default; in this case, files under will be stored in the same file system as .
And on almost all Linux distributions, a tmpfs is mounted on or to store temporary run-time files such as PID files and Unix domain sockets. Temporary system files such as firmware variables are stored in /sys
Implementations
There are several independent variants of the tmpfs concept. One of the earliest was developed by Sun Microsystems for SunOS, and other operating systems like the BSDs and Linux provided their own.
SunOS
SunOS 4 includes what is most likely the earliest implementation of tmpfs; it first appeared in SunOS 4.0 in late 1987, together with new orthogonal address space management that allowed any object to be memory mapped.
The Solaris directory was made a tmpfs file system by default starting with Solaris 2.1, released in December 1992. Output for the Solaris df command will show swap as the background storage for any tmpfs volume:
# df -k
Filesystem kbytes used avail capacity Mounted on
swap 601592 0 601592 0% /tmp/test
Linux
tmpfs is supported by the Linux kernel beginning in version 2.4. Linux tmpfs (previously known as shmfs) is based on the ramfs code used during bootup and also uses the page cache, but unlike ramfs it supports swapping out less-used pages to swap space, as well as filesystem size and inode limits to prevent out of memory situations (defaulting to half of physical RAM and half the number of RAM pages, respectively).
BSD
4.2BSD introduced MFS, a memory-based file system implemented by applying the existing FFS disk filesystem to a virtual memory region.
tmpfs, a memory filesystem implemented using conventional in-memory data structures in order to improve on the performance of MFS, was merged into the official NetBSD source tree on September 10, 2005; it is available in 4.0 and later versions.
FreeBSD has por |
https://en.wikipedia.org/wiki/Rosedale%20Network%20of%20Churches | The Rosedale Network of Churches is a Christian body of Mennonite churches in the Anabaptist tradition. Rosedale Network of Churches was originally formed in 1910 by a group of Amish Mennonites to promote unity while preserving autonomy of the local congregation.
History
For the early history see History of Anabaptist Christianity.
Amish beginnings
The first American settlement of the Amish Mennonites — who in 1693 separated from the main body of Swiss Brethren and followed Jacob Amman — was in Berks County, Pennsylvania, around 1710–1720. Soon they had settlements in Chester and Lancaster counties as well. By the middle of the 19th century, they had congregations from Pennsylvania to Iowa, as well as in Ontario, Canada.
The major division among the Amish
Before the division all factions of the Amish were either called Amish or Amish Mennonites, with no difference in meaning. Mostly in the years between 1862 and 1878 a major division occurred among the Amish, that eventually led to two major factions: The Amish Mennonites and Old Order Amish.
Some of the more liberal minded Amish ministers organized conferences to serve their churches between 1862 and 1878. After the 1878 conference, they became known as the Amish Mennonites and their ministers formed three district conferences: Eastern, Indiana-Michigan, and Western.
Other congregations remained aloof from this conference movement and became forerunners of two groups — the Old Order Amish that formed mostly in the last third of the 19th century and the Conservative (Amish) Mennonite Conference that formed in 1910. Most of the churches of the liberal minded Amish Mennonite conference movement eventually merged with other Mennonite groups.
The Old Order Amish continued to worship in private homes (in the German language) and reject innovations in both worship and lifestyle. Some congregations were theologically in between the extremely conservative Old Order Amish and the more progressive conference Amish Mennonites. These churches did not join the Amish Mennonite conferences, but, unlike the Old Order Amish, were open to the use of meetinghouses, and the organization of missionary, publication, social service, and Sunday school work. Representatives of these congregations met in a conference in Pigeon, Michigan, on November 24–25, 1910, and adopted the name Conservative Amish Mennonite Conference. "Amish" was dropped and the Conservative Mennonite name taken when a revised constitution was adopted in 1957.
Later developments
Concern by some members and churches within the conference over liberalizing tendencies caused a number of congregations and individuals of the Rosedale Network of Churches (then known as the CMC) to splinter or move away from this group to join Conservative Mennonite denominations. The earliest group began to be associated informally together in what was called the Conservative Mennonite Fellowship beginning in 1956 with churches in Ontario, Ohio and elsewhere. I |
https://en.wikipedia.org/wiki/Geoff%20Collyer | Geoff Collyer (born 1958) is a Canadian computer scientist. He is the senior author of C News, a protocol-neutral news transport, and the designer of NOV, the News Overview database (article index) used by all modern newsreaders. He contributed the code that allowed to convert the Bourne Shell from using the non-portable sbrk to a portable malloc based implementation. In the past he worked as a Unix system programmer, but since 1994 he has been living on Plan 9 while working at Bell Laboratories.
Honors
Asteroid 129101 Geoffcollyer, discovered by astronomers at the Jarnac Observatory in Arizona in 2004, was named in his honor. The official was published by the Minor Planet Center on 9 August 2006 ().
References
External links
Geoff Collyers Homepage with publications
modified V7 shell source
modified V9 shell source
recent Plan 9 kernel source
Geoff Collyer and Henry Spencer (1987). News Need Not Be Slow.
Mark Linimon (1994). C News Frequently Asked Questions.
C News source code
1958 births
Living people
Usenet people
Plan 9 people |
https://en.wikipedia.org/wiki/GraphCalc | GraphCalc is an open-source computer program that runs in Microsoft Windows and Linux that provides the functionality of a graphing calculator.
GraphCalc includes many of the standard features of graphing calculators, but also includes some higher-end features:
High resolution
Graphing calculator screens have a resolution typically less than 120×90 pixels, whereas computer monitors typically display 1280x1024 pixels or more.
Speed
Modern computers are considerably faster than handheld graphing calculators
Three-dimensional graphing
While high-end graphing calculators can graph in 3-D, GraphCalc benefits from modern computers' memory, speed, and graphics acceleration (OpenGL)
GraphCalc was developed by Brendan Fields and Mike Arrison, computer science students at Bucknell University, before graduating in 2000. Mike continued the development briefly from 2001–2003, but has since abandoned the project. Other similar projects being maintained are KAlgebra and Cantor.
See also
NuCalc (also known as Graphing Calculator)
External links
GraphCalc Official website
SourceForge project page
KAlgebra official site
Cantor official site
Free plotting software
Free software programmed in C++
Plotting software
Science software for Windows
Science software for Linux
2000 software
Free educational software |
https://en.wikipedia.org/wiki/Rewriting | In mathematics, computer science, and logic, rewriting covers a wide range of methods of replacing subterms of a formula with other terms. Such methods may be achieved by rewriting systems (also known as rewrite systems, rewrite engines, or reduction systems). In their most basic form, they consist of a set of objects, plus relations on how to transform those objects.
Rewriting can be non-deterministic. One rule to rewrite a term could be applied in many different ways to that term, or more than one rule could be applicable. Rewriting systems then do not provide an algorithm for changing one term to another, but a set of possible rule applications. When combined with an appropriate algorithm, however, rewrite systems can be viewed as computer programs, and several theorem provers and declarative programming languages are based on term rewriting.
Example cases
Logic
In logic, the procedure for obtaining the conjunctive normal form (CNF) of a formula can be implemented as a rewriting system. The rules of an example of such a system would be:
(double negation elimination)
(De Morgan's laws)
(distributivity)
where the symbol () indicates that an expression matching the left hand side of the rule can be rewritten to one formed by the right hand side, and the symbols each denote a subexpression. In such a system, each rule is chosen so that the left side is equivalent to the right side, and consequently when the left side matches a subexpression, performing a rewrite of that subexpression from left to right maintains logical consistency and value of the entire expression.
Arithmetic
Term rewriting systems can be employed to compute arithmetic operations on natural numbers.
To this end, each such number has to be encoded as a term.
The simplest encoding is the one used in the Peano axioms, based on the constant 0 (zero) and the successor function S. For example, the numbers 0, 1, 2, and 3 are represented by the terms 0, S(0), S(S(0)), and S(S(S(0))), respectively.
The following term rewriting system can then be used to compute sum and product of given natural numbers.
For example, the computation of 2+2 to result in 4 can be duplicated by term rewriting as follows:
where the rule numbers are given above the rewrites-to arrow.
As another example, the computation of 2⋅2 looks like:
where the last step comprises the previous example computation.
Linguistics
In linguistics, phrase structure rules, also called rewrite rules, are used in some systems of generative grammar, as a means of generating the grammatically correct sentences of a language. Such a rule typically takes the form , where A is a syntactic category label, such as noun phrase or sentence, and X is a sequence of such labels or morphemes, expressing the fact that A can be replaced by X in generating the constituent structure of a sentence. For example, the rule means that a sentence can consist of a noun phrase (NP) followed by a verb phrase (VP); further |
https://en.wikipedia.org/wiki/John%20Tukey | John Wilder Tukey (; June 16, 1915 – July 26, 2000) was an American mathematician and statistician, best known for the development of the fast Fourier Transform (FFT) algorithm and box plot. The Tukey range test, the Tukey lambda distribution, the Tukey test of additivity, and the Teichmüller–Tukey lemma all bear his name. He is also credited with coining the term 'bit' and the first published use of the word 'software'.
Biography
Tukey was born in New Bedford, Massachusetts in 1915, to a Latin teacher father and a private tutor. He was mainly taught by his mother and attended regular classes only for certain subjects like French. Tukey obtained a BA in 1936 and MSc in 1937 in chemistry, from Brown University, before moving to Princeton University, where in 1939 he received a PhD in mathematics after completing a doctoral dissertation titled "On denumerability in topology".
During World War II, Tukey worked at the Fire Control Research Office and collaborated with Samuel Wilks and William Cochran. He is claimed to have helped design the U-2 spy plane. After the war, he returned to Princeton, dividing his time between the university and AT&T Bell Laboratories. In 1962, Tukey was elected to the American Philosophical Society. He became a full professor at 35 and founding chairman of the Princeton statistics department in 1965.
Among many contributions to civil society, Tukey served on a committee of the American Statistical Association that produced a report critiquing the statistical methodology of the Kinsey Report, Statistical Problems of the Kinsey Report on Sexual Behavior in the Human Male, which summarized "A random selection of three people would have been better than a group of 300 chosen by Mr. Kinsey".
From 1960 to 1980, Tukey helped design the NBC television network polls used to predict and analyze elections. He was also a consultant to the Educational Testing Service, the Xerox Corporation, and Merck & Company.
He was awarded the National Medal of Science by President Nixon in 1973. He was awarded the IEEE Medal of Honor in 1982 "For his contributions to the spectral analysis of random processes and the fast Fourier transform (FFT) algorithm".
Tukey retired in 1985. He died in New Brunswick, New Jersey, on July 26, 2000.
Scientific contributions
Early in his career Tukey worked on developing statistical methods for computers at Bell Labs where he invented the term "bit" in 1947.
His statistical interests were many and varied. He is particularly remembered for his development with James Cooley of the Cooley–Tukey FFT algorithm. In 1970, he contributed significantly to what is today known as the jackknife—also termed Quenouille–Tukey jackknife. He introduced the box plot in his 1977 book, "Exploratory Data Analysis".
Tukey's range test, the Tukey lambda distribution, Tukey's test of additivity, Tukey's lemma, and the Tukey window all bear his name. He is also the creator of several little-known methods such as the trimean and |
https://en.wikipedia.org/wiki/Branch%20predictor | In computer architecture, a branch predictor is a digital circuit that tries to guess which way a branch (e.g., an if–then–else structure) will go before this is known definitively. The purpose of the branch predictor is to improve the flow in the instruction pipeline. Branch predictors play a critical role in achieving high performance in many modern pipelined microprocessor architectures.
Two-way branching is usually implemented with a conditional jump instruction. A conditional jump can either be "taken" and jump to a different place in program memory, or it can be "not taken" and continue execution immediately after the conditional jump. It is not known for certain whether a conditional jump will be taken or not taken until the condition has been calculated and the conditional jump has passed the execution stage in the instruction pipeline (see fig. 1).
Without branch prediction, the processor would have to wait until the conditional jump instruction has passed the execute stage before the next instruction can enter the fetch stage in the pipeline. The branch predictor attempts to avoid this waste of time by trying to guess whether the conditional jump is most likely to be taken or not taken. The branch that is guessed to be the most likely is then fetched and speculatively executed. If it is later detected that the guess was wrong, then the speculatively executed or partially executed instructions are discarded and the pipeline starts over with the correct branch, incurring a delay.
The time that is wasted in case of a branch misprediction is equal to the number of stages in the pipeline from the fetch stage to the execute stage. Modern microprocessors tend to have quite long pipelines so that the misprediction delay is between 10 and 20 clock cycles. As a result, making a pipeline longer increases the need for a more advanced branch predictor.
The first time a conditional jump instruction is encountered, there is not much information to base a prediction on. But the branch predictor keeps records of whether branches are taken or not taken. When it encounters a conditional jump that has been seen several times before, then it can base the prediction on the history. The branch predictor may, for example, recognize that the conditional jump is taken more often than not, or that it is taken every second time.
Branch prediction is not the same as branch target prediction. Branch prediction attempts to guess whether a conditional jump will be taken or not. Branch target prediction attempts to guess the target of a taken conditional or unconditional jump before it is computed by decoding and executing the instruction itself. Branch prediction and branch target prediction are often combined into the same circuitry.
Implementation
Static branch prediction
Static prediction is the simplest branch prediction technique because it does not rely on information about the dynamic history of code executing. Instead, it predicts the outcome of a bran |
https://en.wikipedia.org/wiki/RIL | RIL may refer to:
Radio Interface Layer, a software interface used in a mobile device to communicate via mobile networks
RDF Inference Language, a means of expressing expert systems rules and queries that operate on RDF models
Reliance Industries Limited, a corporation in India
Rice Lane railway station, England; National Rail station code RIL
Recombinant Inbred Lines, a population derived from multiply inbred strains in order to study complex genetic traits which normally have large variation for a specific trait/traits
The FAA and IATA identifier for Garfield County Regional Airport in Rifle, Colorado
Randesund IL
See also
Rill |
https://en.wikipedia.org/wiki/YTV%20%28Canadian%20TV%20channel%29 | YTV is a Canadian English language discretionary specialty channel owned by YTV Canada, Inc., a subsidiary of Corus Entertainment. The channel and its programming is targeted at children and young teenagers; consisting of original live action and animated television series, movies, and third party shows from various U.S.-based kids networks such as Nickelodeon. Its name was originally thought to be an abbreviation for "Youth Television", though the channel's website has denied this.
The channel was launched on September 1, 1988 by owners Rogers Media and CUC Broadcasting upon launch. In 1995, Shaw Communications acquired CUC's 34% stake and in 1998, it acquired Rogers' remaining interest of the channel, before Shaw's media division was spun off to form Corus Entertainment in 1999.
YTV operates two time shifted feeds, running on both Eastern and Pacific Time Zone schedules, and is available in over 11.0 million households in Canada as of 2013.
History
The channel was licensed by the Canadian Radio-television and Telecommunications Commission (CRTC) in 1987 by Rogers Cable and CUC Broadcasting.
The channel launched on September 1, 1988, at 7:00 p.m., with the first program being a special party celebrating the launch of YTV, hosted by John Candy. At launch, Rogers held 75% of the channel while CUC owned 25%.
In 1995, Calgary-based Shaw Communications acquired CUC's stake of 34% ownership of YTV. Shaw acquired Rogers' remaining share in 1998 to take full control of it. In 1999, the media assets of Shaw were spun off to form Corus Entertainment.
Two Corus specialty channel applications for YTV extensions, YTV POW!, an internationally sourced kids' action, adventure and superhero genre, and YTV OneWorld, targeting children from age 9 to 17 with travel, humour, games, and STEM were approved on September 18, 2008. The YTV Oneworld license was used to launch Nickelodeon Canada.
On January 11, 2011, a high-definition feed was launched.
Programming
Current YTV original programming include hosted programming blocks, such as The Zone. In addition to original programming, YTV has historically acquired and co-produced programming with the U.S cable network Nickelodeon.
Programming blocks
Current
The Zone (September 2, 1991–present)
The Zone Weekend
Big Fun Movies (January 2, 2011–present)
Seasonal
Mucho Marcho - This block airs movies every March.
Fang-Tastic - This block airs Halloween specials and movies every October. (Ongoing at this moment)
Merry Everything - This block airs holiday specials and movies all December long. It was previously known as "Big Fun Holidays" from 2009 to 2011, and "Merry 6mas" from 2012 to 2016.
Former
The Treehouse (1994–98)
YTV Jr. (September 7, 1998 – 2002)
YTV PlayTime (2010–12)
Bionix (September 10, 2004 – February 7, 2010)
CRUNCH (September 9, 2006 – September 28, 2013)
Big Fun Weeknights
Big Fun Fridays
3 Hairy Thumbs Up (October 19, 2002 to August 31, 2008)
Moovibot (September 5, 2008 – Septe |
https://en.wikipedia.org/wiki/Exploratory%20data%20analysis | In statistics, exploratory data analysis (EDA) is an approach of analyzing data sets to summarize their main characteristics, often using statistical graphics and other data visualization methods. A statistical model can be used or not, but primarily EDA is for seeing what the data can tell us beyond the formal modeling and thereby contrasts traditional hypothesis testing. Exploratory data analysis has been promoted by John Tukey since 1970 to encourage statisticians to explore the data, and possibly formulate hypotheses that could lead to new data collection and experiments. EDA is different from initial data analysis (IDA), which focuses more narrowly on checking assumptions required for model fitting and hypothesis testing, and handling missing values and making transformations of variables as needed. EDA encompasses IDA.
Overview
Tukey defined data analysis in 1961 as: "Procedures for analyzing data, techniques for interpreting the results of such procedures, ways of planning the gathering of data to make its analysis easier, more precise or more accurate, and all the machinery and results of (mathematical) statistics which apply to analyzing data."
Exploratory data analysis is an analysis technique to analyze and investigate the data set and summaries the main characteristics of the dataset. Main advantage of EDA is providing the data visualization of data after conducting the analysis.
Tukey's championing of EDA encouraged the development of statistical computing packages, especially S at Bell Labs. The S programming language inspired the systems S-PLUS and R. This family of statistical-computing environments featured vastly improved dynamic visualization capabilities, which allowed statisticians to identify outliers, trends and patterns in data that merited further study.
Tukey's EDA was related to two other developments in statistical theory: robust statistics and nonparametric statistics, both of which tried to reduce the sensitivity of statistical inferences to errors in formulating statistical models. Tukey promoted the use of five number summary of numerical data—the two extremes (maximum and minimum), the median, and the quartiles—because these median and quartiles, being functions of the empirical distribution are defined for all distributions, unlike the mean and standard deviation; moreover, the quartiles and median are more robust to skewed or heavy-tailed distributions than traditional summaries (the mean and standard deviation). The packages S, S-PLUS, and R included routines using resampling statistics, such as Quenouille and Tukey's jackknife and Efron bootstrap, which are nonparametric and robust (for many problems).
Exploratory data analysis, robust statistics, nonparametric statistics, and the development of statistical programming languages facilitated statisticians' work on scientific and engineering problems. Such problems included the fabrication of semiconductors and the understanding of communications networks |
https://en.wikipedia.org/wiki/Uncomfortable%20science | Uncomfortable science, as identified by statistician John Tukey, comprises situations in which there is a need to draw an inference from a limited sample of data, where further samples influenced by the same cause system will not be available. More specifically, it involves the analysis of a finite natural phenomenon for which it is difficult to overcome the problem of using a common sample of data for both exploratory data analysis and confirmatory data analysis. This leads to the danger of systematic bias through testing hypotheses suggested by the data.
A typical example is Bode's law, which provides a simple numerical rule for the distances of the planets in the Solar System from the Sun. Once the rule has been derived, through the trial and error matching of various rules with the observed data (exploratory data analysis), there are not enough planets remaining for a rigorous and independent test of the hypothesis (confirmatory data analysis). We have exhausted the natural phenomena. The agreement between data and the numerical rule should be no surprise, as we have deliberately chosen the rule to match the data. If we are concerned about what Bode's law tells us about the cause system of planetary distribution then we demand confirmation that will not be available until better information about other planetary systems becomes available.
See also
Cosmic variance for an extreme example of this phenomenon
Data mining
Bibliography
References
Philosophy of statistics
Statistical hypothesis testing |
https://en.wikipedia.org/wiki/Oneword | Oneword Radio was a British commercial digital radio station featuring books, drama, comedy, children's programming, and discussion. The station was available in the UK via digital radio (DAB) and digital television (Freeview DVB-T and Sky Digital DVB-S) and was streamed on the internet 24 hours a day worldwide. It was launched on 2 May 2000.
Ownership was shared between UBC Media Group and Channel 4 between early 2005 and December 2007. In October 2005, Channel 4 increased its stake to a majority by buying 51% of Oneword for £1 million. At 7.30 on weekday mornings, Oneword carried the Channel 4 Radio daily news broadcast The Morning Report, which was produced by the Channel 4 news team.
Virgin Media removed OneWord from its ex-NTL cable channel lineup on 4 October 2007. Oneword was not on its ex-Telewest lineup at the time.
In December 2007, Channel 4 decided to withdraw its funding, selling its share back to UBC Media Group for £1. All programming was replaced by repeats of previous output. On 1 January 2008 the remaining staff were dismissed. Oneword ceased broadcasting on DAB on Friday 11 January 2008.
After broadcasting ended, birdsong was broadcast on the channel until a permanent replacement, Amazing Radio, came on air on 1 June 2009.
References
Defunct radio stations in the United Kingdom
Digital-only radio stations
Radio stations established in 2000
Radio stations disestablished in 2008
Channel 4 Radio |
https://en.wikipedia.org/wiki/Gullane%20Entertainment | Gullane Entertainment PLC was a British independent production company which produced children's programming, including Thomas & Friends (1984–2021), Shining Time Station (1989–1995), and The Magic Adventures of Mumfie (1994–1998). The company was purchased by HIT Entertainment in July 2002, and went defunct within the same year. As of today, most of Gullane's library is currently owned by toy company Mattel as a result of their subsequent acquisition of HIT Entertainment.
History
The Britt Allcroft Company
The company produced the first seven seasons of Thomas the Tank Engine & Friends as Britt Allcroft Company, after Britt Allcroft purchased the rights to The Railway Series in 1979.
In the late 1980s, the company formed Quality Family Entertainment an American subsidiary to produce an adapted version of the series, Shining Time Station.
In 1994, the company announced a strategic international alliance with Canadian-based company Catalyst Entertainment, who previously co-produced Shining Time Station with TBAC.
In June 1997, the company announced they had purchased the rights to Captain Pugwash and would produce a new television series featuring the character. In 1998, the company acquired the publishing rights to The Railway Series from Reed Elsevier. Later that year, the company formed a motion picture subsidiary in the UK, Gullane Pictures, to produce feature films.
In December 1999, The Britt Allcroft Company announced they had acquired a 50% stake on Sooty from then-owner from Sooty International Limited, forming a joint-venture company called Bridgefilms (also known as Sooty Limited), which would also handle licensing rights to existing Britt Allcroft creation Mumfie.
In March 2000, HIT Entertainment offered a $363 million bid to purchase the company, alongside other interested companies. In the same month, the company announced they had purchased The Media Merchants for £14 million, bringing Art Attack to their list of intellectual properties (IPs).
In September 2000, after the cinematic failure of Thomas and the Magic Railroad, Britt Allcroft stepped down as the company's CEO and soon, it was later reformed as Gullane Entertainment.
Gullane Entertainment
In September 2000, with the negative reception and box-office disappointment of Thomas and the Magic Railroad, Britt Allcroft stepped down as the company's CEO, and under new leadership, the company announced they would rebrand as Gullane Entertainment in order to expand and export their brands worldwide. Britt Allcroft would however remain as a creative consultant for the Thomas the Tank Engine franchise. Within the announcement of the name change came some new projects, including a new series of Thomas the Tank Engine & Friends, the launch of an online platform called Planet Gullane, a new series of Art Attack alongside the production of 238 episodes for the international market in a partnership with The Walt Disney Company, a second series of Sooty Heights alongside the produ |
https://en.wikipedia.org/wiki/Application%20checkpointing | Checkpointing is a technique that provides fault tolerance for computing systems. It basically consists of saving a snapshot of the application's state, so that applications can restart from that point in case of failure. This is particularly important for long running applications that are executed in failure-prone computing systems.
Checkpointing in distributed systems
In the distributed computing environment, checkpointing is a technique that helps tolerate failures that otherwise would force long-running application to restart from the beginning. The most basic way to implement checkpointing, is to stop the application, copy all the required data from the memory to reliable storage (e.g., parallel file system) and then continue with the execution. In case of failure, when the application restarts, it does not need to start from scratch. Rather, it will read the latest state ("the checkpoint") from the stable storage and execute from that. While there is ongoing debate on whether checkpointing is the dominating I/O workload on distributed computing systems, there is general consensus that checkpointing is one of the major I/O workloads.
There are two main approaches for checkpointing in the distributed computing systems: coordinated checkpointing and uncoordinated checkpointing. In the coordinated checkpointing approach, processes must ensure that their checkpoints are consistent. This is usually achieved by some kind of two-phase commit protocol algorithm. In the uncoordinated checkpointing, each process checkpoints its own state independently. It must be stressed that simply forcing processes to checkpoint their state at fixed time intervals is not sufficient to ensure global consistency. The need for establishing a consistent state (i.e., no missing messages or duplicated messages) may force other processes to roll back to their checkpoints, which in turn may cause other processes to roll back to even earlier checkpoints, which in the most extreme case may mean that the only consistent state found is the initial state (the so-called domino effect).
Implementations for applications
Save State
One of the original and now most common means of application checkpointing was a "save state" feature in interactive applications, in which the user of the application could save the state of all variables and other data to a storage medium at the time they were using it and either continue working, or exit the application and at a later time, restart the application and restore the saved state. This was implemented through a "save" command or menu option in the application. In many cases it became standard practice to ask the user if they had unsaved work when exiting the application if they wanted to save their work before doing so.
This sort of functionality became extremely important for usability in applications where the particular work could not be completed in one sitting (such as playing a video game expected to take dozens of hours, |
https://en.wikipedia.org/wiki/Timeline%20of%20algorithms | The following timeline of algorithms outlines the development of algorithms (mainly "mathematical recipes") since their inception.
Medieval Period
Before – writing about "recipes" (on cooking, rituals, agriculture and other themes)
c. 1700–2000 BC – Egyptians develop earliest known algorithms for multiplying two numbers
c. 1600 BC – Babylonians develop earliest known algorithms for factorization and finding square roots
c. 300 BC – Euclid's algorithm
c. 200 BC – the Sieve of Eratosthenes
263 AD – Gaussian elimination described by Liu Hui
628 – Chakravala method described by Brahmagupta
c. 820 – Al-Khawarizmi described algorithms for solving linear equations and quadratic equations in his Algebra; the word algorithm comes from his name
825 – Al-Khawarizmi described the algorism, algorithms for using the Hindu–Arabic numeral system, in his treatise On the Calculation with Hindu Numerals, which was translated into Latin as Algoritmi de numero Indorum, where "Algoritmi", the translator's rendition of the author's name gave rise to the word algorithm (Latin algorithmus) with a meaning "calculation method"
c. 850 – cryptanalysis and frequency analysis algorithms developed by Al-Kindi (Alkindus) in A Manuscript on Deciphering Cryptographic Messages, which contains algorithms on breaking encryptions and ciphers
c. 1025 – Ibn al-Haytham (Alhazen), was the first mathematician to derive the formula for the sum of the fourth powers, and in turn, he develops an algorithm for determining the general formula for the sum of any integral powers, which was fundamental to the development of integral calculus
c. 1400 – Ahmad al-Qalqashandi gives a list of ciphers in his Subh al-a'sha which include both substitution and transposition, and for the first time, a cipher with multiple substitutions for each plaintext letter; he also gives an exposition on and worked example of cryptanalysis, including the use of tables of letter frequencies and sets of letters which can not occur together in one word
Before 1940
1540 – Lodovico Ferrari discovered a method to find the roots of a quartic polynomial
1545 – Gerolamo Cardano published Cardano's method for finding the roots of a cubic polynomial
1614 – John Napier develops method for performing calculations using logarithms
1671 – Newton–Raphson method developed by Isaac Newton
1690 – Newton–Raphson method independently developed by Joseph Raphson
1706 – John Machin develops a quickly converging inverse-tangent series for π and computes π to 100 decimal places
1768 – Leonard Euler publishes his method for numerical integration of ordinary differential equations in problem 85 of Institutiones calculi integralis
1789 – Jurij Vega improves Machin's formula and computes π to 140 decimal places,
1805 – FFT-like algorithm known by Carl Friedrich Gauss
1842 – Ada Lovelace writes the first algorithm for a computing engine
1903 – A fast Fourier transform algorithm presented by Carle David Tolmé Runge
1918 - S |
https://en.wikipedia.org/wiki/Physical%20Address%20Extension | In computing, Physical Address Extension (PAE), sometimes referred to as Page Address Extension,
is a memory management feature for the x86 architecture. PAE was first introduced by Intel in the Pentium Pro, and later by AMD in the Athlon processor. It defines a page table hierarchy of three levels (instead of two), with table entries of 64 bits each instead of 32, allowing these CPUs to directly access a physical address space larger than 4 gigabytes (232 bytes).
The page table structure used by x86-64 CPUs when operating in long mode further extends the page table hierarchy to four or more levels, extending the virtual address space, and uses additional physical address bits at all levels of the page table, extending the physical address space. It also uses the topmost bit of the 64-bit page table entry as a no-execute or "NX" bit, indicating that code cannot be executed from the associated page. The NX feature is also available in protected mode when these CPUs are running a 32-bit operating system, provided that the operating system enables PAE.
History
PAE was first implemented in the Intel Pentium Pro in 1995, although the accompanying chipsets usually lacked support for the required extra address bits.
PAE is supported by the Pentium Pro, Pentium II, Pentium III, and Pentium 4 processors. The first Pentium M family processors ("Banias") introduced in 2003 also support PAE; however, they do not show the PAE support flag in their CPUID information. This was remedied in a later revision of the "Dothan" core in 2005. It was also available on AMD processors including the AMD Athlon (although the chipsets are limited to 32-bit addressing) and later AMD processor models.
When AMD defined their 64-bit extension of the industry standard x86 architecture, AMD64 or x86-64, they also enhanced the paging system in "long mode" based on PAE.
It supports 64-bit virtual addresses ( 48 bits are implemented on some processors and 57 bits are implemented on others), 52-bit physical addresses,
and includes NX bit functionality.
When the x86-64 processor is initialized, the PAE feature is required to be enabled before the processor is switched from Legacy Mode to Long Mode.
Design
With PAE, the page table entry of the x86 architecture is enlarged from 32 to 64 bits. This allows more room for the physical page address, or "page frame number" field, in the page table entry. In the initial implementations of PAE the page frame number field was expanded from 20 to 24 bits. The size of the "byte offset" from the address being translated is still 12 bits, so total physical address size increases from 32 bits to 36 bits (i.e. from 20+12 to 24+12). This increased the physical memory that is theoretically addressable by the CPU from 4 GB to 64 GB.
In the first processors that supported PAE, support for larger physical addresses is evident in their package pinout, with address pin designations going up to A35 instead of stopping at A31. Later processor familie |
https://en.wikipedia.org/wiki/Testing%20hypotheses%20suggested%20by%20the%20data | In statistics, hypotheses suggested by a given dataset, when tested with the same dataset that suggested them, are likely to be accepted even when they are not true. This is because circular reasoning (double dipping) would be involved: something seems true in the limited data set; therefore we hypothesize that it is true in general; therefore we wrongly test it on the same, limited data set, which seems to confirm that it is true. Generating hypotheses based on data already observed, in the absence of testing them on new data, is referred to as post hoc theorizing (from Latin post hoc, "after this").
The correct procedure is to test any hypothesis on a data set that was not used to generate the hypothesis.
The general problem
Testing a hypothesis suggested by the data can very easily result in false positives (type I errors). If one looks long enough and in enough different places, eventually data can be found to support any hypothesis. Yet, these positive data do not by themselves constitute evidence that the hypothesis is correct. The negative test data that were thrown out are just as important, because they give one an idea of how common the positive results are compared to chance. Running an experiment, seeing a pattern in the data, proposing a hypothesis from that pattern, then using the same experimental data as evidence for the new hypothesis is extremely suspect, because data from all other experiments, completed or potential, has essentially been "thrown out" by choosing to look only at the experiments that suggested the new hypothesis in the first place.
A large set of tests as described above greatly inflates the probability of type I error as all but the data most favorable to the hypothesis is discarded. This is a risk, not only in hypothesis testing but in all statistical inference as it is often problematic to accurately describe the process that has been followed in searching and discarding data. In other words, one wants to keep all data (regardless of whether they tend to support or refute the hypothesis) from "good tests", but it is sometimes difficult to figure out what a "good test" is. It is a particular problem in statistical modelling, where many different models are rejected by trial and error before publishing a result (see also overfitting, publication bias).
The error is particularly prevalent in data mining and machine learning. It also commonly occurs in academic publishing where only reports of positive, rather than negative, results tend to be accepted, resulting in the effect known as publication bias.
Correct procedures
All strategies for sound testing of hypotheses suggested by the data involve including a wider range of tests in an attempt to validate or refute the new hypothesis. These include:
Collecting confirmation samples
Cross-validation
Methods of compensation for multiple comparisons
Simulation studies including adequate representation of the multiple-testing actually involved
Henry Scheffé's |
https://en.wikipedia.org/wiki/Macintosh%20LC%20II | The Macintosh LC II is a personal computer designed, manufactured, and sold by Apple Computer from March 1992 to March 1993. The LC II is an update to the original Macintosh LC, replacing its Motorola 68020 processor with a 68030 and increasing the onboard memory to 4 MB. The LC II was priced at US$1,699, fully $800 less than the original LC when it was introduced.
In September 1992, Apple introduced the Macintosh Performa family of consumer-oriented computers. The LC II was repackaged as the Performa 400. When LC II was replaced by the Macintosh LC III in early 1993, the LC II was discontinued in North America, and two new Performa models (the 405 and 430) were introduced in its place. In October, the Performa 400, 405 and 430 were all discontinued and a new LC II-based model called the Performa 410 was introduced which became Apple's new entry-level computer. The LC II continued to be sold in some markets for some time after that.
The LC II was Apple's highest-selling Macintosh product in 1992.
Overview
The LC II retains the original LC's 16-bit system bus and 10 MB RAM limit, making its performance roughly the same as the earlier model. The main benefit of the 68030 processor in the LC II is its onboard paged memory management unit, which System 7 uses to enable its new virtual memory feature. Apple had opted to get a quick update to the LC out the door instead of spending the additional time required to do a full architectural update, which would happen the following year with the Macintosh LC III.
The LC II was sold at the same time as the Macintosh IIsi, which was more than $800 more expensive than the LC II, but did not have its 10 MB memory limit, 16-bit data bus, and mono audio output. The IIsi also includes a NuBus expansion slot that the LC II lacks, and can be powered on via a button on the keyboard, unlike the LC range which has a power switch on the back of the unit.
Hardware
Case: The LC II retains its predecessor's pizza box form factor. The design was updated during the LC II's production run when the auto-inject floppy drive was substituted for a manual-inject unit. The revised front bezel no longer featured the horizontal indentation aligning with the floppy drive, a defining characteristic of the Snow White design language.
Logic board: The LC II retains much of the original LC's logic board design, including a 16-bit data path and a 10 MB memory limit. These limitations limited the machine's ability to take full advantage of the 68030 CPU.
Storage: The LC II shipped with one floppy drive as standard, with options for 40 or 80 MB hard drives. While the original LC had two internal floppy drive connectors, the LC II has one. About 5% of the LC units sold had two floppy drives, and internal hard disks were becoming common by 1992, so the second connector was removed.
Video: The LC II's logic board has one video RAM slot, which is filled with a 256 KB SIMM as standard; the high-end configuration was shipped wi |
https://en.wikipedia.org/wiki/David%20Marr%20%28neuroscientist%29 | David Courtenay Marr (19 January 1945 – 17 November 1980) was a British neuroscientist and physiologist. Marr integrated results from psychology, artificial intelligence, and neurophysiology into new models of visual processing. His work was very influential in computational neuroscience and led to a resurgence of interest in the discipline.
Biography
Born in Woodford, Essex, and educated at Rugby School; he was admitted at Trinity College, Cambridge on 1 October 1963 (having been awarded an Open Scholarship and the Lees Knowles Rugby Exhibition).
He was awarded the Coutts Trotter Scholarship in 1966 and obtained his BA in mathematics the same year. He was elected a Research Fellow of Trinity College, Cambridge in 1968. His doctoral dissertation, supervised by Giles Brindley, was submitted in 1969 and described his model of the function of the cerebellum based mainly on anatomical and physiological data garnered from a book by J.C. Eccles. His interest turned from general brain theory to visual processing. Subsequently, he worked at the Massachusetts Institute of Technology, where he took on a faculty appointment in the Department of Psychology in 1977 and was subsequently made a tenured full professor in 1980. Marr proposed that understanding the brain requires an understanding of the problems it faces and the solutions it finds. He emphasised the need to avoid general theoretical debates and instead focus on understanding specific problems.
Marr died of leukemia in Cambridge, Massachusetts, at the age of 35. His findings are collected in the book Vision: A computational investigation into the human representation and processing of visual information, which was finished mainly in the summer of 1979, was published in 1982 after his death and re-issued in 2010 by The MIT Press. This book had a key role in the beginning and rapid growth of computational neuroscience field. He was married to Lucia M. Vaina of Boston University's Department of Biomedical Engineering and Neurology.
There are various academic awards and prizes named in his honour. The Marr Prize, one of the most prestigious awards in computer vision, the David Marr Medal awarded every two years by the Applied Vision Association in the UK, and the Cognitive Science Society also awards a Marr Prize for the best student paper at its annual conference.
Work
Theories of cerebellum, hippocampus, and neocortex
Marr is best known for his work on vision, but before he began work on that topic he published three seminal papers proposing computational theories of the cerebellum (in 1969), neocortex (in 1970), and hippocampus (in 1971). Each of those papers presented important new ideas that continue to influence modern theoretical thinking.
The cerebellum theory was motivated by two unique features of cerebellar anatomy: (1) the cerebellum contains vast numbers of tiny granule cells, each receiving only a few inputs from "mossy fibers"; (2) Purkinje cells in the cerebellar cortex each |
https://en.wikipedia.org/wiki/Light%20Weight%20Kernel%20Threads | Light Weight Kernel Threads (LWKT) is a computer science term and from DragonFly BSD in particular. LWKTs differ from normal kernel threads in that they can preempt normal kernel threads. According to Matt Dillon, DragonFlyBSD creator:
See also
Light-weight process
Thread (computing)
Sources
Matt Dillon's post about the LWKT scheduler
Threads (computing)
DragonFly BSD |
https://en.wikipedia.org/wiki/Unreal%20Engine | Unreal Engine (UE) is a series of 3D computer graphics game engines developed by Epic Games, first showcased in the 1998 first-person shooter video game Unreal. Initially developed for PC first-person shooters, it has since been used in a variety of genres of games and has seen adoption by other industries, most notably the film and television industry. Unreal Engine is written in C++ and features a high degree of portability, supporting a wide range of desktop, mobile, console, and virtual reality platforms.
The latest generation, Unreal Engine 5, was launched in April 2022. Its source code is available on GitHub, and commercial use is granted based on a royalty model, with Epic charging 5% of revenues over US$1 million, which is waived for games published on the Epic Games Store. Epic has included features from acquired companies like Quixel in the engine, which is seen as helped by Fortnite's revenue.
In 2014, Unreal Engine was named the world's "most successful videogame engine" by Guinness World Records.
History
First generation
The first-generation Unreal Engine was developed by Tim Sweeney, the founder of Epic Games. Having created editing tools for his shareware games ZZT (1991) and Jill of the Jungle (1992), Sweeney began writing the engine in 1995 for the production of a game that would later become a first-person shooter known as Unreal. After years in development, it debuted with the game's release in 1998, although MicroProse and Legend Entertainment had access to the technology much earlier, licensing it in 1996. According to an interview, Sweeney wrote 90 percent of the code in the engine, including the graphics, tools, and networking system.
At first, the engine relied completely on software rendering, meaning the graphics calculations were handled by the central processing unit (CPU). However, over time, it was able to take advantage of the capabilities provided by dedicated graphics cards, focusing on the Glide API, specially designed for 3dfx accelerators. While OpenGL and Direct3D were supported, they reported a slower performance compared to Glide due to their deficiency in texture management at the time. Sweeney particularly criticized the quality of OpenGL drivers for consumer hardware, describing them as "extremely problematic, buggy, and untested", and labeled the code in the implementation as "scary" as opposed to the simpler and cleaner support for Direct3D. With regard to audio, Epic employed the Galaxy Sound System, a software created in assembly language that integrated both EAX and Aureal technologies, and allowed the use of tracker music, which gave level designers flexibility in how a game soundtrack was played at a specific point in maps. Steve Polge, the author of the Reaper Bots plugin for Quake, programmed the artificial intelligence system, based on knowledge he had gained at his previous employer IBM designing router protocols.
According to Sweeney, the hardest part of the engine to program was the r |
https://en.wikipedia.org/wiki/Freakazoid%21 | Freakazoid! is an American superhero comedy animated television series created by Bruce Timm and Paul Dini and developed by Tom Ruegger for the Kids' WB programming block of The WB. The series chronicles the adventures of the title character, Freakazoid, a crazy teenage superhero who fights crime in Washington, D.C. It also featured mini-episodes with the adventures of other bizarre superheroes. The series was produced by Warner Bros. Animation and Amblin Television, being the third animated series produced by the collaboration of Steven Spielberg and Warner Bros. Animation after Tiny Toon Adventures and Animaniacs.
Bruce Timm, best known as a producer of the DC Animated Universe, originally intended it to be a straightforward superhero action-adventure cartoon with comic overtones, but executive producer Steven Spielberg requested it to be a flat-out comedy. The show is similar to fellow Ruegger-led programs such as Animaniacs, having a unique style of humor that includes slapstick, fourth wall breaking, parody, surreal humour, and pop culture references.
The series was one of the first to debut on the new Kids' WB Saturday morning block of The WB, on September 9, 1995. The series lasted for two seasons, finishing with 24 episodes, the final one broadcast on June 1, 1997. Although the series originally struggled in the ratings, reruns on Cartoon Network and a fan following elevated it to become a cult hit. Warner Bros. considered renewing the series for a third season, but deemed it to be too expensive. The show also ranked #53 on IGN's Top 100 Animated Series list.
Background
The show's title character is the superhero alter ego of geeky 16-year-old (later changed to 17-year-old) Dexter Douglas who attends Harry Connick Jr. High School. His name is an allusion to the alliterative names that superheroes commonly have. Dexter gained his abilities from a computer bug activated by a "secret key sequence" that was accidentally activated by his cat Mr. Chubbikins (a reference to the Pentium FDIV bug). The sequence of keys is "@[=g3,8d]\&fbb=-q]/hk%fg" (the quotes are included) which also activated when Dexter hit the delete button on his computer. Freakazoid has enhanced strength and endurance, extraordinary speed and agility, as well as access to all the knowledge on the Internet. These make him a powerful and fearsome force for upholding freedom and righteousness, unless he gets distracted by something like a bear riding a motorcycle. He has a base called the Freakalair, a parody of the Batcave, built by his mute butler Ingmar. The Freakalair contains a "Hall of Nifty Things to Know" and even a mad scientist lab. His greatest weakness, as he once explained to Guitierrez, is graphite bars charged with negative ions. He also expresses a great aversion to "poo gas".
Freakazoid also has a variety of other abilities: he once developed telekinesis powered by anger that was never mentioned again after the episode, and once crossed the globe to yell at |
https://en.wikipedia.org/wiki/Cross%20%28boxing%29 | In boxing, a straight or cross (also commonly called or a rear hand punch) are punches usually thrown with the dominant hand
and are power punches like the uppercut and hook. Compubox, a computerized punch scoring system, counts the straight and cross as power punches.
The Straight/Cross remains one of the most common methods of knockout across combat sports including boxing, kickboxing, and MMA.
Technique
From the guard position, the rear hand is thrown from the chin, travelling towards the target in a straight line. The rear shoulder is comes forward and finishes touching the outside of the chin. For cover, the lead hand can be retracted and tucked against the face to protect the inside of the chin. For additional power, the torso and hips rotate counterclockwise (for right-hand dominant, and clockwise for left-hand dominant) as the straight/cross is thrown. Weight is also transferred from the rear foot to the lead foot, resulting in the rear heel turning outwards to transfer weight. Body rotation and the sudden weight transfer is what gives the straight/cross its power.
If it is thrown the instant an opponent leads with the same side hand, the blow crosses over the leading arm, hence its name. If the rear hand instead travels inside the opponent's guard, it is a straight.
It is commonly used to set up a hook. The straight/cross can also follow a jab, creating the classic "one-two combo".
References
External links
Boxing terminology
Kickboxing terminology
Punches (combat) |
https://en.wikipedia.org/wiki/CompuBox | CompuBox is the name of a computerized punches scoring system run by two operators. CompuBox is used in boxing matches around the world.
Background
The system is based on a computer program, originally named FightStat, developed by Jon Gibbs in 1984–85 when Gibbs worked with Logan Hobson and Robert Canobbio at Sports Information Data Base (SIDB), of Hasbrouck Heights, New Jersey.
Gibbs was the developer of TenniSTAT, the first computer-generated statistics program for tennis, which was used by the US Open, Wimbledon, the Australian Open, and other major tournaments.
At Hobson & Canobbio's request, Gibbs wrote the code for FightStat (also called PunchStat in some venues) and was used at Madison Square Garden's Felt Forum and in Reno for the 1985 HBO Boxing telecast of the Livingstone Bramble-Ray Mancini rematch for the WBA's world Lightweight title.
After SIDB went bankrupt in 1985, Hobson and Canobbio renamed the program CompuBox and founded CompuBox Inc. Hobson later left the company in 2002.
CompuBox's purpose is to settle controversies surrounding fights by counting each punch thrown by each of the fighters, and also each punch landed, to provide fight viewers with a final punchstat count and a perception of who should ideally be given the judges' decision, in the cases where a fight lasts the full distance.
The system calls for two operators. Each operator watches one of the two fighters and has access to four keys, corresponding to jab connect, jab miss, power punch connect, and power punch miss. The operators key in the different punches as they happen, collecting punch counts and hit percentages along the way.
CompuBox is used by HBO, NBC and ESPN. Former world champion Genaro Hernandez was one of the men in charge of operating the system.
References
Sources
"Compubox Online"
Jones, Robert. "Interview With the Owner of CompuBox: Bob Canobbio", Mike Marley's FightNightNews.com, accessed February 12, 2008.
Perry, Kevin. "Fight Report Exclusive-Compubox Interview", Fight Report, accessed February 12, 2008.
Boxing
Sports software |
https://en.wikipedia.org/wiki/Adler-32 | Adler-32 is a checksum algorithm written by Mark Adler in 1995, modifying Fletcher's checksum. Compared to a cyclic redundancy check of the same length, it trades reliability for speed. Adler-32 is more reliable than Fletcher-16, and slightly less reliable than Fletcher-32.
History
The Adler-32 checksum is part of the widely used zlib compression library, as both were developed by Mark Adler.
A "rolling checksum" version of Adler-32 is used in the rsync utility.
Calculation
An Adler-32 checksum is obtained by calculating two 16-bit checksums A and B and concatenating their bits into a 32-bit integer. A is the sum of all bytes in the stream plus one, and B is the sum of the individual values of A from each step.
At the beginning of an Adler-32 run, A is initialized to 1, B to 0. The sums are done modulo 65521 (the largest prime number smaller than 216). The bytes are stored in network order (big endian), B occupying the two most significant bytes.
The function may be expressed as
A = 1 + D1 + D2 + ... + Dn (mod 65521)
B = (1 + D1) + (1 + D1 + D2) + ... + (1 + D1 + D2 + ... + Dn) (mod 65521)
= n×D1 + (n−1)×D2 + (n−2)×D3 + ... + Dn + n (mod 65521)
Adler-32(D) = B × 65536 + A
where D is the string of bytes for which the checksum is to be calculated, and n is the length of D.
Example
The Adler-32 sum of the ASCII string "Wikipedia" would be calculated as follows:
A = 920 = 0x398 (base 16)
B = 4582 = 0x11E6
Output = (0x11E6 << 16) + 0x398 = 0x11E60398 = 300286872
The modulo operation had no effect in this example, since none of the values reached 65521.
Comparison with the Fletcher checksum
The first difference between the two algorithms is that Adler-32 sums are calculated modulo a prime number, whereas Fletcher sums are calculated modulo 24−1, 28−1, or 216−1 (depending on the number of bits used), which are all composite numbers. Using a prime number makes it possible for Adler-32 to catch differences in certain combinations of bytes that Fletcher is unable to detect.
The second difference, which has the largest effect on the speed of the algorithm, is that the Adler sums are computed over 8-bit bytes rather than 16-bit words, resulting in twice the number of loop iterations. This results in the Adler-32 checksum taking between one-and-a-half to two times as long as Fletcher's checksum for 16-bit word aligned data. For byte-aligned data, Adler-32 is faster than a properly implemented Fletcher's checksum (e.g., one found in the Hierarchical Data Format).
Example implementation
In C, an inefficient but straightforward implementation is :
const uint32_t MOD_ADLER = 65521;
uint32_t adler32(unsigned char *data, size_t len)
/*
where data is the location of the data in physical memory and
len is the length of the data in bytes
*/
{
uint32_t a = 1, b = 0;
size_t index;
// Process each byte of the data in order
for (index = 0; index < len; ++index)
{
a = (a + data[index]) % MOD_A |
https://en.wikipedia.org/wiki/Resistor%E2%80%93transistor%20logic | Resistor–transistor logic (RTL), sometimes also known as transistor–resistor logic (TRL), is a class of digital circuits built using resistors as the input network and bipolar junction transistors (BJTs) as switching devices. RTL is the earliest class of transistorized digital logic circuit; it was succeeded by diode–transistor logic (DTL) and transistor–transistor logic (TTL).
RTL circuits were first constructed with discrete components, but in 1961 it became the first digital logic family to be produced as a monolithic integrated circuit. RTL integrated circuits were used in the Apollo Guidance Computer, whose design began in 1961 and which first flew in 1966.
Implementation
RTL inverter
A bipolar transistor switch is the simplest RTL gate (inverter or NOT gate) implementing logical negation. It consists of a common-emitter stage with a base resistor connected between the base and the input voltage source. The role of the base resistor is to expand the very small transistor input voltage range (about 0.7 V) to the logical "1" level (about 3.5 V) by converting the input voltage into current. Its resistance is settled by a compromise: it is chosen low enough to saturate the transistor and high enough to obtain high input resistance. The role of the collector resistor is to convert the collector current into voltage; its resistance is chosen high enough to saturate the transistor and low enough to obtain low output resistance (high fan-out).
One-transistor RTL NOR gate
With two or more base resistors (R3 and R4) instead of one, the inverter becomes a two-input RTL NOR gate (see the figure on the right). The logical operation OR is performed by applying consecutively the two arithmetic operations addition and comparison (the input resistor network acts as a parallel voltage summer with equally weighted inputs and the following common-emitter transistor stage as a voltage comparator with a threshold about 0.7 V). The equivalent resistance of all the resistors connected to logical "1" and the equivalent resistance of all the resistors connected to logical "0" form the two legs of a composed voltage divider driving the transistor. The base resistances and the number of the inputs are chosen (limited) so that only one logical "1" is sufficient to create base-emitter voltage exceeding the threshold and, as a result, saturating the transistor. If all the input voltages are low (logical "0"), the transistor is cut-off. The pull-down resistor R1 biases the transistor to the appropriate on-off threshold. The output is inverted since the collector-emitter voltage of transistor Q1 is taken as output, and is high when the inputs are low. Thus, the analog resistive network and the analog transistor stage perform the logic function NOR.
Multi-transistor RTL NOR gate
The limitations of the one-transistor RTL NOR gate are overcome by the multi-transistor RTL implementation. It consists of a set of parallel-connected transistor switches driven by the l |
https://en.wikipedia.org/wiki/SystemRescue | SystemRescue (Previously known as "SystemRescueCD") is a Linux distribution for x86 64 and x86 computers. The primary purpose of SystemRescue is to repair unbootable or otherwise damaged computer systems after a system crash. SystemRescue is not intended to be used as a permanent operating system. It runs from a Live CD, a USB flash drive or any type of hard drive. It was designed by a team led by François Dupoux, and is based on Arch Linux since version 6.0. Starting with version 6.0, it has systemd as its init system.
Features
SystemRescue is capable of graphics using the Linux framebuffer option for tools such as GParted. It has options such as connecting to the Internet through an ADSL modem or Ethernet and graphical web browsers such as Mozilla Firefox.
SystemRescue features include:
GNU Parted and GParted to partition disks and resize partitions, including FAT32 and NTFS
fdisk to edit the disk partition table
PartImage - disk imaging software which copies only used sectors
TestDisk - to recover lost partition and PhotoRec to recover lost data
smartmontools - a S.M.A.R.T. suite for HDD health reporting and data loss prevention
ddrescue - to extract recoverable data from physically damaged HDD and listing damaged sectors
FSArchiver - a system tool that allows you to save the contents of a file-system to a compressed archive file
nwipe - a secure data erasure tool (fork of DBAN) for harddrives to remove data remanence, supports Gutmann method plus other overwriting standard algorithms and patterns.
A CD and DVD burner - dvd+rw-tools
Two bootloaders - GRUB and SYSLINUX
Web browsers - Firefox, ELinks
File manager - emelFM2
Archiving and unarchiving abilities
File system tools - file system create, delete, resize, move
Support for many file systems, including full NTFS read/write access (via NTFS-3G) as well as FAT32 and Mac OS HFS
Support for Intel x86 and PowerPC systems, including Macs
Ability to create a boot disk for operating systems
Support for Windows Registry editing and password changing from Linux
Can boot FreeDOS, Memtest86+, hardware diagnostics and other boot disks from a single CD
Burning DVDs and system backup
The CD can also boot from a customized DVD which has almost 4.6 GB of free space for backed-up files. This makes it good for storing all the information that is needed from a hard drive and then formatting it. To burn the DVD, one must burn the image file first and then add all the separate files and folders. This should not affect the general way in which the DVD works. The DVD can then be used to insert those files into the hard drive using Midnight Commander.
See also
Parted Magic
List of bootable data recovery software
References
External links
Arch-based Linux distributions
Free data recovery software
Free security software
Linux distributions
Live USB
Operating system distributions bootable from read-only media |
https://en.wikipedia.org/wiki/Cellular | Cellular may refer to:
Cellular automaton, a model in discrete mathematics
Cell biology, the evaluation of cells work and more
Cellular (film), a 2004 movie
Cellular frequencies, assigned to networks operating in cellular RF bands
Cellular manufacturing
Cellular network, cellular radio networks
U.S. Cellular Field, also known as "The Cell", a baseball stadium in Chicago
U.S. Cellular Arena, an arena in Milwaukee, Wisconsin
Terms such as cellular organization, cellular structure, cellular system, and so on may refer to:
Cell biology, the evaluation of how cells work and more
Cellular communication networks, systems for allowing communication through mobile phones and other mobile devices
Cellular organizational structures, methods of human organization in social groups
Clandestine cell organizations, entities organized to commit crimes, acts of terror, or other malicious activities
See also
Cell (disambiguation) |
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