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https://en.wikipedia.org/wiki/Database%20engine | A database engine (or storage engine) is the underlying software component that a database management system (DBMS) uses to create, read, update and delete (CRUD) data from a database. Most database management systems include their own application programming interface (API) that allows the user to interact with their underlying engine without going through the user interface of the DBMS.
The term "database engine" is frequently used interchangeably with "database server" or "database management system". A "database instance" refers to the processes and memory structures of the running database engine.
Storage engines
Many of the modern DBMS support multiple storage engines within the same database. For example, MySQL supports InnoDB as well as MyISAM.
Some storage engines are transactional.
Additional engine types include:
Embedded database engines
In-memory database engines
Design considerations
Information in a database is stored as bits laid out as data structures in storage that can be efficiently read from and written to given the properties of hardware. Typically the storage itself is designed to meet requirements of various areas that extensively utilize storage, including databases. A DBMS in operation always simultaneously utilizes several storage types (e.g., memory, and external storage), with respective layout methods.
In principle the database storage can be viewed as a linear address space, where every bit of data has its unique address in this address space. In practice, only a very small percentage of addresses are kept as initial reference points (which also requires storage); most data is accessed by indirection using displacement calculations (distance in bits from the reference points) and data structures which define access paths (using pointers) to all needed data in an effective manner, optimized for the needed data access operations.
Database storage hierarchy
A database, while in operation, resides simultaneously in several types of storage, forming a storage hierarchy. By the nature of contemporary computers most of the database part inside a computer that hosts the DBMS resides (partially replicated) in volatile storage. Data (pieces of the database) that are being processed/manipulated reside inside a processor, possibly in processor's caches. These data are being read from/written to memory, typically through a computer bus (so far typically volatile storage components). Computer memory is communicating data (transferred to/from) external storage, typically through standard storage interfaces or networks (e.g., fibre channel, iSCSI). A storage array, a common external storage unit, typically has storage hierarchy of its own, from a fast cache, typically consisting of (volatile and fast) DRAM, which is connected (again via standard interfaces) to drives, possibly with different speeds, like flash drives and magnetic disk drives (non-volatile). The drives may be connected to magnetic tapes, on which typically |
https://en.wikipedia.org/wiki/QED%20manifesto | The QED manifesto was a proposal for a computer-based database of all mathematical knowledge, strictly formalized and with all proofs having been checked automatically. (Q.E.D. means in Latin, meaning "which was to be demonstrated.")
Overview
The idea for the project arose in 1993, mainly under the impetus of Robert Boyer. The goals of the project, tentatively named QED project or project QED, were outlined in the QED manifesto, a document first published in 1994, with input from several researchers. Explicit authorship was deliberately avoided. A dedicated mailing list was created, and two scientific conferences on QED took place, the first one in 1994 at Argonne National Laboratories and the second in 1995 in Warsaw organized by the Mizar group.
The project seems to have dissolved by 1996, never having produced more than discussions and plans. In a 2007 paper, Freek Wiedijk identifies two reasons for the failure of the project. In order of importance:
Very few people are working on formalization of mathematics. There is no compelling application for fully mechanized mathematics.
Formalized mathematics does not yet resemble real, traditional mathematics. This is partly due to the complexity of mathematical notation, and partly to the limitations of existing theorem provers and proof assistants; the paper finds that the major contenders, Mizar, HOL, and Coq, have serious shortcomings in their abilities to express mathematics.
Nonetheless, QED-style projects are regularly proposed. The Mizar Mathematical Library formalizes a large portion of undergraduate mathematics, and was considered the largest such library in 2007. Similar projects include the Metamath proof database and the mathlib library written in Lean.
In 2014 the Twenty years of the QED Manifesto workshop was organized as part of the Vienna Summer of Logic.
See also
Formalism (mathematics)
Mathematical knowledge management
POPLmark, a more modest project in programming language theory
References
Further reading
H. Barendregt & F. Wiedijk, The Challenge of Computer Mathematics, Transactions A of the Royal Society 363 no. 1835, 2351–2375, 2005
(open access issue)
Richard A. De Millo, Richard J. Lipton, Alan J. Perlis, Social processes and proofs of theorems and programs, Communications of the ACM, Volume 22, Issue 5 (May 1979), Pages: 271 - 280
John Harrison, Formalized Mathematics, Technical Report 36, Turku Centre for Computer Science (TUCS)
Ittay Weiss, The QED Manifesto after Two Decades Version 2.0, Journal of Software vol. 11, no. 8, pp. 803-815, 2016.
External links
Freek Wiedijk, Formalizing 100 Theorems A page keeping track of the progress in the formalization of 100 common theorems.
Freek Wiedijk, The Seventeen Provers of the World, a proof of the irrationality of the square root of two in seventeen different proof assistants.
Formalized Mathematics a journal in which Mizar proofs are presented.
The Archive of Formal Proofs a similar (refereed) repo |
https://en.wikipedia.org/wiki/DBase | dBase (also stylized dBASE) was one of the first database management systems for microcomputers and the most successful in its day. The dBase system included the core database engine, a query system, a forms engine, and a programming language that tied all of these components together.
Originally released as Vulcan for PTDOS in 1978, the CP/M port caught the attention of Ashton-Tate in 1980. They licensed it, re-released it as dBASE II, and later ported it to IBM PC computers running DOS. On the PC platform in particular, dBase became one of the best-selling software titles for a number of years. A major upgrade was released as dBase III and ported to a wider variety of platforms, including UNIX and VMS. By the mid-1980s, Ashton-Tate was one of the "big three" software publishers in the early business-software market, along with Lotus Development and WordPerfect.
Starting in the mid-1980s, several companies produced their own variations on the dBase product and especially the dBase programming language. These included FoxBASE+ (later renamed FoxPro), Clipper, and other so-called xBase products. Many of these were technically stronger than dBase, but could not push it aside in the market. This changed with the poor reception of dBase IV, whose design and stability were so lacking that many users switched to other products.
In the early 1990s, xBase products constituted the leading database platform for implementing business applications. The size and impact of the xBase market did not go unnoticed, and within one year, the three top xBase firms were acquired by larger software companies:
Borland purchased Ashton-Tate
Microsoft bought Fox Software
Computer Associates acquired Nantucket
By the opening decade of the 21st century, most of the original xBase products had faded from prominence and many had disappeared entirely. Products known as dBase still exist, owned by dBase LLC.
History
Origins
In the late 1960s, Fred Thompson at the Jet Propulsion Laboratory (JPL) was using a Tymshare product named RETRIEVE to manage a database of electronic calculators, which were at that time very expensive products. In 1971, Thompson collaborated with Jack Hatfield, a programmer at JPL, to write an enhanced version of RETRIEVE, which became the JPLDIS project. JPLDIS was written in FORTRAN on the UNIVAC 1108 mainframe, and was presented publicly in 1973. When Hatfield left JPL in 1974, Jeb Long took over his role.
While working at JPL as a contractor, C. Wayne Ratliff entered the office football pool. He had no interest in the game as such, but felt he could win the pool by processing the post-game statistics found in newspapers. In order to do this, he turned his attention to a database system and, by chance, came across the documentation for JPLDIS. He used this as the basis for a port to PTDOS on his kit-built IMSAI 8080 microcomputer, and called the resulting system Vulcan (after the home planet of Mr. Spock on Star Trek).
Ashton-Tate
George Ta |
https://en.wikipedia.org/wiki/Vladimir%20Vapnik | Vladimir Naumovich Vapnik (; born 6 December 1936) is a computer scientist, researcher, and academic. He is one of the main developers of the Vapnik–Chervonenkis theory of statistical learning and the co-inventor of the support-vector machine method and support-vector clustering algorithms.
Early life and education
Vladimir Vapnik was born to a Jewish family in the Soviet Union. He received his master's degree in mathematics from the Uzbek State University, Samarkand, Uzbek SSR in 1958 and Ph.D in statistics at the Institute of Control Sciences, Moscow in 1964. He worked at this institute from 1961 to 1990 and became Head of the Computer Science Research Department.
Academic career
At the end of 1990, Vladimir Vapnik moved to the USA and joined the Adaptive Systems Research Department at AT&T Bell Labs in Holmdel, New Jersey. While at AT&T, Vapnik and his colleagues did work on the support-vector machine, which he also worked on much earlier before moving to the USA. They demonstrated its performance on a number of problems of interest to the machine learning community, including handwriting recognition. The group later became the Image Processing Research Department of AT&T Laboratories when AT&T spun off Lucent Technologies in 1996. In 2000, Vapnik and neural networks expert, Hava Siegelmann developed Support-Vector Clustering, which enabled the algorithm to categorize inputs without labels - becoming one of the most ubiquitous data clustering applications in use. Vapnik left AT&T in 2002 and joined NEC Laboratories in Princeton, New Jersey, where he worked in the Machine Learning group. He also holds a Professor of Computer Science and Statistics position at Royal Holloway, University of London since 1995, as well as a position as Professor of Computer Science at Columbia University, New York City since 2003. As of February 1, 2021, he has an h-index of 86 and, overall, his publications have been cited 226597 times. His book on "The Nature of Statistical Learning Theory" alone has been cited 91650 times.
On November 25, 2014, Vapnik joined Facebook AI Research, where he is working alongside his longtime collaborators Jason Weston, Léon Bottou, Ronan Collobert, and Yann LeCun.
In 2016, he also joined Peraton Labs.
Honors and awards
Vladimir Vapnik was inducted into the U.S. National Academy of Engineering in 2006. He received the 2005 Gabor Award, the 2008 Paris Kanellakis Award, the 2010 Neural Networks Pioneer Award, the 2012 IEEE Frank Rosenblatt Award, the 2012 Benjamin Franklin Medal in Computer and Cognitive Science from the Franklin Institute, the 2013 C&C Prize from the NEC C&C Foundation, the 2014 Kampé de Fériet Award, the 2017
IEEE John von Neumann Medal. In 2018, he received the Kolmogorov Medal from University of London and delivered the Kolmogorov Lecture. In 2019, Vladimir Vapnik received
BBVA Foundation Frontiers of Knowledge Award.
Selected publications
On the uniform convergence of relative frequencies of events to the |
https://en.wikipedia.org/wiki/Million%20Book%20Project | The Million Book Project (or the Universal Library) was a book digitization project led by Carnegie Mellon University School of Computer Science and University Libraries from 2007 to 2008. Working with government and research partners in India (Digital Library of India) and China, the project scanned books in many languages, using OCR to enable full text searching, and providing free-to-read access to the books on the web. , they have completed the scanning of 1 million books and have made the entire catalog accessible online.
Description
The Million Book Project was a 501(c)(3) charity organization with various scanning centers throughout the world.
By December 2007, more than 1.5 million books had been scanned, in 20 languages: 970,000 in Chinese; 360,000 in English; 50,000 in Telugu; and 40,000 in Arabic. Most of the books are in the public domain, but permission has been acquired to include over 60,000 copyrighted books (roughly 53,000 in English and 7,000 in Indian languages). The books are mirrored in part at sites in India, China, Carnegie Mellon, the Internet Archive, Bibliotheca Alexandrina. The books that have been scanned to date are not yet all available online, and no single site has copies of all the books that are available online.
The million book project was a "proof of concept" that has largely been replaced by HathiTrust, Google Book Search and the Internet Archive book scanning projects.
The Internet Archive may have some books that Google does not (e.g.: The Poems of Robert Frost published after the end of 1922).
The National Science Foundation (NSF) awarded Carnegie Mellon $3.63M over four years for equipment and administrative travel for the Million Book Project. India provided $25M annually to support language translation research projects. The Ministry of Education in China provided $8.46M over three years. The Internet Archive provided equipment, staff and money. The University of California, Merced Library funded the work to acquire copyright permission from U.S. publishers.
The program ended in 2008.
Partner institutions
China
The institutions in China which are participants in this project include:
Ministry of Education of the People's Republic of China
Chinese Academy of Science
Fudan University
Nanjing University
Peking University
Tsinghua University
Zhejiang University
Northeast Normal University
India
The institutions in India which are participants in this project include:
Indian Institute of Science, Bangalore
International Institute of Information Technology, Hyderabad
Indian Institute of Information Technology, Allahabad
Anna University, Chennai
Mysore University, Mysore
University of Pune, Pune
Goa University, Goa
Tirumala Tirupati Devasthanams, Tirupathi
Shanmugha Arts, Science, Technology & Research Academy, Tanjore
Kalasalingam Academy of Research and Education, Srivilliputhur
Maharashtra Industrial Development Corporation, Mumbai
United States
The institutions in the U.S. whic |
https://en.wikipedia.org/wiki/Macintosh%20SE/30 | The Macintosh SE/30 is a personal computer designed, manufactured and sold by Apple Computer from January 1989 to October 1991. It is the fastest of the original black-and-white compact Macintosh series.
The SE/30 has a black-and-white monitor and a single Processor Direct Slot (rather than the NuBus slots of the IIx, with which the SE/30 shares a common architecture) which supported third-party accelerators, network cards, or a display adapter. The SE/30 could expand up to 128 MB of RAM (a significant amount of RAM at the time), and included a 40 or 80 MB hard drive. It was also the first compact Mac to include a 1.44 MB high density floppy disk drive as standard (late versions of the SE had one, but earlier versions did not). The power of the SE/30 was demonstrated by its use to produce the This Week newspaper, the first colour tabloid newspaper in the UK to use new, digital pre-press technology on a personal, desktop computer. In keeping with Apple's practice, from the Apple II+ until the Power Macintosh G3 was announced, a logic board upgrade was available for US$1,699 to convert a regular SE to an SE/30. The SE would then have exactly the same specs as an SE/30, with the difference only in the floppy drive if the SE had an 800 KB drive. The set included a new front bezel to replace the original SE bezel with that of an SE/30.
Although this machine was succeeded in Q4 of 1990 by the Macintosh Classic, the SE/30 wasn't discontinued until 1991 by the Macintosh Classic II, which despite featuring the same processor and clock speed, was only 60% as fast as the SE/30 due to its 16-bit data path, supported no more than 10 MB of memory, lacked an internal expansion slot, and made the Motorola 68882 FPU an optional upgrade.
Hardware
Although the Motorola 68030 in the SE/30 supports 32-bit addressing, the SE/30 ROM, like the IIx ROM, includes some code using 24-bit addressing, rendering the ROM "32-bit dirty". This limits the actual amount of RAM that can be accessed to 8 MB under System 6.0.8. A system extension called MODE32 enables access to installed extra memory under System 6.0.8. Under System 7.0 up to System 7.5.5 the SE/30 can use up to 128 MB of RAM. Alternatively, replacing the ROM SIMM with one from a Mac IIsi or Mac IIfx makes the SE/30 "32-bit clean" and thereby enables use of up to 128 MB RAM and System 7.5 through OS 7.6.1.
A standard SE/30 can run up to System 7.5.5, since Mac OS 7.6 requires a "32-bit clean" ROM.
Additionally, the SE/30 can run A/UX, Apple's older version of Unix that was able to run Macintosh programs.
Though there was no official upgrade path for the SE/30, several third-party processor upgrades were available. A 68040 upgrade made it possible to run Mac OS 8.1, which extended the SE/30's productive life for many more years.
Also extending the useful life of the SE30 were Micron Technology video cards. Three cards were available, which fit into the SE/30's Processor Direct Slot: the 8-bit Gray-Scale 30, t |
https://en.wikipedia.org/wiki/Macintosh%20IIci | The Macintosh IIci is a personal computer designed, manufactured, and sold by Apple Computer, Inc. from September 1989 to February 1993. It is a more powerful version of the Macintosh IIcx, released earlier that year, and shares the same compact case design. With three NuBus expansion slots and a Processor Direct Slot, the IIci also improved upon the IIcx's 16 MHz Motorola 68030 CPU and 68882 FPU, replacing them with 25 MHz versions of these chips.
The Macintosh Quadra 700 was introduced at the end of 1991 as Apple's mainstream workstation product to replace the IIci, albeit at a significantly higher price point: by this time, Apple authorized resellers were offering entry-level IIci systems for US$4,000 or less, whereas the Quadra 700 entered the market above US$6,000. Because of this, Apple continued to sell the IIci until early 1993 when the less expensive Quadra 650 and comparably-priced Quadra 800 were introduced.
Hardware
The IIci introduced several technical and architectural enhancements, some of which were important in preparing for System 7 (which was then called the Blue project) and would influence future Macintoshes, though some of them came at the cost of compatibility:
a new, 32-bit clean ROM with built-in 32-bit QuickDraw that consists of two parts: one part that is the same across all Macintoshes, and another area (called the overpatch area) that is specific to each Macintosh.
discontiguous physical memory that is mapped into a contiguous memory area by the MMU. Some of the System 7 virtual memory functions had to be added to the ROM to support getting the physical address of the memory.
an optional 32 KB Level 2 cache. The cache card, which fit into the Processor Direct Slot (initially called a "cache connector" by Apple), was later included in all systems at no charge. Third-party cards offered up to 128 KB, but the added cache size yielded little benefit over the base card.
a first for a modular Macintosh — onboard graphics for an external display. This freed one of the system's three NuBus slots. However, because the integrated graphics used the system's RAM for its framebuffer, some users used a NuBus graphics card to reclaim the lost memory. Also, it was popular to install faster memory in the first bank of SIMM slots, as this is the bank used by the video subsystem. The onboard graphics supported up to 8-bit color at resolutions of either 640x480 or 512x384.
The IIci was one of the most popular and longest-lived Macintosh models of the 20th century. For much of its lifespan, it was the business "workhorse" of the Macintosh line. For a short time in 1989, before the introduction of the 40 MHz Macintosh IIfx, the IIci was the fastest Mac available.
The IIci came with either a 40- or an 80-megabyte hard disk.
Upgradability
Possible upgrades include the 40 or 50 MHz DayStar PowerCache 68030, a 33 or 40 MHz DayStar Turbo 040, and the DayStar Turbo 601 PowerPC Upgrade running at either 66 MHz or 100 MHz. DayStar Di |
https://en.wikipedia.org/wiki/Data%20Display%20Debugger | Data Display Debugger (GNU DDD) is a graphical user interface (using the Motif toolkit) for command-line debuggers such as GDB, DBX, JDB, HP Wildebeest Debugger, XDB, the Perl debugger, the Bash debugger, the Python debugger, and the GNU Make debugger. DDD is part of the GNU Project and distributed as free software under the GNU General Public License.
Technical details
DDD has GUI front-end features such as viewing source texts and its interactive graphical data display, where data structures are displayed as graphs.
DDD is used primarily on Unix systems, and its usefulness is complemented by many open source plug-ins available for it.
Notes & references
References
Notes
See also
Debugger front-end
KDbg, a KDE debugger front-end
ups (debugger)
External links
Source code
Debuggers
GNU Project software
Unix programming tools
Software that uses Motif (software) |
https://en.wikipedia.org/wiki/Liberal%20International | Liberal International (LI) is a worldwide organization of liberal political parties. The political international was founded in Oxford in 1947 and has become the pre-eminent network for liberal parties aiming to strengthen liberalism around the world. Its headquarters are at 1 Whitehall Place, London, SW1A 2HD, within the National Liberal Club. The Oxford Manifesto describes the basic political principles of the Liberal International, which is currently made up of 111 parties and organizations.
Aims
The Liberal International Constitution (2005) gives its purposes as: The principles that unite member parties from Africa, America, Asia and Europe are respect for human rights, free and fair elections and multi-party democracy, social justice, tolerance, market economy, free trade, environmental sustainability and a strong sense of international solidarity.
The aims of Liberal International are also set out in a series of seven manifestos, written between 1946 and 1997, and are furthered by a variety of bodies including a near-yearly conference for liberal parties and individuals from around the world.
Bureau
The bureau of Liberal International is elected every 18 months by the delegates of the congress.
The 14th president of Liberal International is Hakima el Haite of the Mouvement Populaire (Morocco), is a former Minister of Environment, UN climate champion, and climate scientist. Madam El Haite succeeded Dr Juli Minoves, formerly Andorra's foreign minister and representative to the United Nations.
Former Presidents include Hans Van Baalen MEP, John, Lord Alderdice, Dutch politician and former European Commissioner Frits Bolkestein, German politician Otto Graf Lambsdorff, and Spain's first democratically elected prime minister after Francoist Spain, Adolfo Suárez.
The secretary-general of Liberal International is Gordon Mackay, a former Member of the National Assembly of South Africa. Other members of the bureau include Deputy President Prof. Karl-Heinz Paque; and Vice Presidents Cellou Dalein Diallo (Guinea), Kitty Monterrey (Nicaragua), Abir al-Sahlani (Sweden), Kiat Sittheamorn (Thailand) and Robert Woodthorpe Browne (United Kingdom). There are two elected treasurers, Judith Pallares MP (Andorra) and Minister Omar Youm (Senegal).
Awards
Liberal International awards prizes to individuals in the areas of human rights and liberalism.
Prize for Freedom:
The Liberal International Prize for Freedom is LI's most prestigious human rights award. Conveyed annually since 1984 to an individual of liberal conviction who has made outstanding efforts for the defence of freedom and human rights, recipients include Maria Corina Machado of Venezuela, Senator Leila de Lima of the Philippines, Raif Badawi of Saudi Arabia, Waris Dirie of Somalia and Vaclav Havel of Czechoslovakia and the Czech Republic.
Medal of Liberalism:
The Liberal International Medal of Liberalism is awarded to individuals who have worked to advance liberal values on a local, nat |
https://en.wikipedia.org/wiki/SIM%20lock | A SIM lock, simlock, network lock, carrier lock or (master) subsidy lock is a technical restriction built into GSM and CDMA mobile phones by mobile phone manufacturers for use by service providers to restrict the use of these phones to specific countries and/or networks. This is in contrast to a phone (retrospectively called SIM-free or unlocked) that does not impose any SIM restrictions.
Generally phones can be locked to accept only SIM cards with certain International Mobile Subscriber Identities (IMSIs); IMSIs may be restricted by:
Mobile country code (MCC; e.g., will only work with SIM issued in one country)
Mobile network code (MNC; e.g., AT&T Mobility, T-Mobile, Vodafone, Bell Mobility etc.)
Mobile subscriber identification number (MSIN; i.e., only one SIM can be used with the phone)
Additionally, some phones, especially Nokia phones, are locked by group IDs (GIDs), restricting them to a single Mobile virtual network operator (MVNO) of a certain operator.
Most mobile phones can be unlocked to work with any GSM network provider, but the phone may still display the original branding and may not support features of the new carrier. Besides the locking, phones may also have firmware installed on them which is specific to the network provider. For example, a Vodafone or Telstra branded phone in Australia will display the relevant logo and may only support features provided by that network (e.g. Vodafone Live!). This firmware is installed by the service provider and is separate from the locking mechanism. Most phones can be unbranded by reflashing a different firmware version, a procedure recommended for advanced users only. The reason many network providers SIM lock their phones is that they offer phones at a discount to customers in exchange for a contract to pay for the use of the network for a specified time period, usually between one and three years. This business model allows the company to recoup the cost of the phone over the life of the contract. Such discounts are worth up to several hundred US dollars. If the phones were not locked, users might sign a contract with one company, get the discounted phone, then stop paying the monthly bill (thus breaking the contract) and start using the phone on another network or even sell the phone for a profit. SIM locking curbs this by prohibiting change of network (using a new SIM).
In some countries, SIM locking is very common if subsidized phones are sold with prepaid contracts. It is important to note, however, that the technology associated with the phone must be compatible with the technology being used by the network carrier. A GSM cell phone will only work with a GSM carrier and will not work on a CDMA network provider. Likewise, a CDMA cell phone will only work with a CDMA carrier and will not work on a GSM network provider. Note that newer (2013+) high end mobile phones are capable of supporting both CDMA and GSM technologies, allowing customers to use their mobile devices on |
https://en.wikipedia.org/wiki/Ruud%20de%20Wild | Rudolf Alexander de Wild (born 24 April 1969) is a Dutch radio host. He is also a former DJ, VJ and was one of the faces of the now-defunct television network Talpa.
On 6 May 2002, when he worked for radio station 3FM, he interviewed Pim Fortuyn. After the interview De Wild and Fortuyn stepped outside where De Wild witnessed the assassination of Fortuyn. De Wild stated that he narrowly avoided being shot himself and suffered from trauma and PTSD as a result of witnessing Fortuyn's murder.
In 2004, De Wild started his show Ruuddewild.nl on Radio 538. He got a timeslot between 16.00 and 19.00. At that time he also worked for the television channel Talpa of John de Mol. He presented Big Brother 5 together with Bridget Maasland.
Conflict with Radio 538
In the summer of 2007, De Wild did not return to present his program on Radio 538 after his holiday. Official statements said De Wild was suffering from burnout, but rumours circulated that he had tried to break out of his contract with Radio 538 because he felt that he was not getting enough creative freedom from the station. His show Ruuddewild.nl went on without him, and was presented by Lindo Duvall, another deejay at Radio 538.
Because the show was still called Ruuddewild.nl, and Radio 538 repeatedly stated that De Wild really was ill, it appeared De Wild was going to return. But on 25 October 2007, Ruuddewild.nl disappeared from Radio 538's schedule and was replaced by a nameless afternoon show, still presented by Lindo Duvall. Radio 538 then stated it had terminated De Wild's contract.
Return to Dutch Radio
On 10 March 2008, Ruud de Wild started presenting the morning-show on Dutch radio station Q-Music, again called Ruuddewild.nl. Sidekick on this new show is Jeroen Kijk in de Vegte, who worked with De Wild before at 3FM, and producer is Martijn Zuurveen. In 2010, Ruud de Wild went back to Radio 538. His contract was terminated in April 2015, when 538 suddenly announced his slot was to be taken over by the Coen en Sander Show. De Wild now works for NPO Radio 2.
Personal
In 2019 he had a relationship with fashion designer Olcay Gulsen. The couple separated in 2023.
External links
Ruud de Wild (official website)
References
1969 births
Living people
Dutch game show hosts
Big Brother (Dutch TV series)
Crime witnesses
People from Hilversum |
https://en.wikipedia.org/wiki/Canadian%20Trusted%20Computer%20Product%20Evaluation%20Criteria | The Canadian Trusted Computer Product Evaluation Criteria (CTCPEC) is a computer security standard published in 1993 by the Communications Security Establishment to provide an evaluation criterion on IT products. It is a combination of the TCSEC (also called Orange Book) and the European ITSEC approaches.
CTCPEC led to the creation of the Common Criteria standard.
The Canadian System Security Centre, part of the Communications Security Establishment was founded in 1988 to establish a Canadian computer security standard.
The Centre published a draft of the standard in April 1992. The final version was published in January 1993.
References
External links
Computer security standards |
https://en.wikipedia.org/wiki/Declarative%20programming | In computer science, declarative programming is a programming paradigm—a style of building the structure and elements of computer programs—that expresses the logic of a computation without describing its control flow.
Many languages that apply this style attempt to minimize or eliminate side effects by describing what the program must accomplish in terms of the problem domain, rather than describing how to accomplish it as a sequence of the programming language primitives (the how being left up to the language's implementation). This is in contrast with imperative programming, which implements algorithms in explicit steps.
Declarative programming often considers programs as theories of a formal logic, and computations as deductions in that logic space. Declarative programming may greatly simplify writing parallel programs.
Common declarative languages include those of database query languages (e.g., SQL, XQuery), regular expressions, logic programming (e.g. Prolog, Datalog, answer set programming), functional programming, and configuration management systems.
The term is often used in contrast to imperative programming, which dictates the transformation steps of its state explicitly.
Definition
Declarative programming is often defined as any style of programming that is not imperative. A number of other common definitions attempt to define it by simply contrasting it with imperative programming. For example:
A high-level program that describes what a computation should perform.
Any programming language that lacks side effects (or more specifically, is referentially transparent)
A language with a clear correspondence to mathematical logic.
These definitions overlap substantially.
Declarative programming is a non-imperative style of programming in which programs describe their desired results without explicitly listing commands or steps that must be performed. Functional and logic programming languages are characterized by a declarative programming style. In logic programming, programs consist of sentences expressed in logical form, and computation uses those sentences to solve problems, which are also expressed in logical form.
In a pure functional language, such as Haskell, all functions are without side effects, and state changes are only represented as functions that transform the state, which is explicitly represented as a first-class object in the program. Although pure functional languages are non-imperative, they often provide a facility for describing the effect of a function as a series of steps. Other functional languages, such as Lisp, OCaml and Erlang, support a mixture of procedural and functional programming.
Some logic programming languages, such as Prolog, and database query languages, such as SQL, while declarative in principle, also support a procedural style of programming.
Subparadigms
Declarative programming is an umbrella term that includes a number of better-known programming paradigms.
Constraint programming |
https://en.wikipedia.org/wiki/BMP | BMP may refer to:
Computing
Basic Multilingual Plane, related to the Unicode character set
Beep Media Player, an obsolete media player related to XMMS
BMP file format, an image file format with the extension .bmp
BGP Monitoring Protocol (RFC 7854), a network protocol for monitoring BGP sessions
Vehicles
BMP development, a series of Soviet and Russian infantry fighting vehicles
BMP-1
BMP-2
BMP-3
BMP-23, a Bulgarian infantry fighting vehicle
BMP UAV, a series of Chinese unmanned aerial vehicles
Medical
Basic metabolic panel, a common blood test
Bone morphogenetic proteins, a family of growth factors influencing bone and tissue growth within animals
Other uses
Besi Merah Putih, a militia group in East Timor
Best management practice for water pollution, a technical term in environmental management
BMP Global Distribution Inc v Bank of Nova Scotia, a 2008–2009 case in the Supreme Court of Canada
BMP Radio, a broadcasting company based in Houston, Texas
Boase Massimi Pollitt, a former advertising agency in UK
Stone Beit Midrash Program, an undergraduate Judaic Studies program at Yeshiva University
Bear Mountain Parkway, a scenic parkway in New York State that connects the Bear Mountain Bridge with Peekskill
Baoding East railway station, China Railway telegraph code BMP
British Mandate Palestine, Geopolitical entity from 1920 to 1948
See also |
https://en.wikipedia.org/wiki/ALGOL%20W | ALGOL W is a programming language. It is based on a proposal for ALGOL X by Niklaus Wirth and Tony Hoare as a successor to ALGOL 60. ALGOL W is a relatively simple upgrade of the original ALGOL 60, adding string, bitstring, complex number and reference to record data types and call-by-result passing of parameters, introducing the while statement, replacing switch with the case statement, and generally tightening up the language.
Wirth's entry was considered too little of an advance over ALGOL 60, and the more complex entry from Adriaan van Wijngaarden that would later become ALGOL 68 was selected in a highly contentious meeting. Wirth later published his version as A contribution to the development of ALGOL. With a number of small additions, this eventually became ALGOL W.
Wirth supervised a high quality implementation for the IBM System/360 at Stanford University that was widely distributed. The implementation was written in PL360, an ALGOL-like assembly language designed by Wirth. The implementation includes influential debugging and profiling abilities.
ALGOL W served as the basis for the Pascal language, and the syntax of ALGOL W will be immediately familiar to anyone with Pascal experience. The key differences are improvements to record handling in Pascal, and, oddly, the loss of ALGOL W's ability to define the length of an array at runtime, which is one of Pascal's most-complained-about features.
Syntax and semantics
ALGOL W's syntax is built on a subset of the EBCDIC character encoding set. In ALGOL 60, reserved words are distinct lexical items, but in ALGOL W they are only sequences of characters, and do not need to be stropped. Reserved words and identifiers are separated by spaces. In these ways ALGOL W's syntax resembles that of Pascal and later languages.
The ALGOL W Language Description defines ALGOL W in an affix grammar that resembles Backus–Naur form (BNF). This formal grammar was a precursor of the Van Wijngaarden grammar.
Much of ALGOL W's semantics is defined grammatically:
Identifiers are distinguished by their definition within the current scope. For example, a ⟨procedure identifier⟩ is an identifier that has been defined by a procedure declaration, a ⟨label identifier⟩ is an identifier that is being used as a goto label.
The types of variables and expressions are represented by affixes. For example ⟨τ function identifier⟩ is the syntactic entity for a function that returns a value of type τ, if an identifier has been declared as an integer function in the current scope then that is expanded to ⟨integer function identifier⟩.
Type errors are grammatical errors. For example, ⟨integer expression⟩ / ⟨integer expression⟩ and ⟨real expression⟩ / ⟨real expression⟩ are valid but distinct syntactic entities that represent expressions, but ⟨real expression⟩ DIV ⟨integer expression⟩ (i.e., integer division performed on a floating-point value) is an invalid syntactic entity.
Example
This demonstrates ALGOL W's record type f |
https://en.wikipedia.org/wiki/With%20This%20Ring%20%28TV%20series%29 | With This Ring (originally known as Happily Ever After) was a prime time panel show aired by the DuMont Television Network on Sundays from January 21, 1951, to March 11, 1951.
The show featured engaged white, opposite-sex couples discussing marriage and marital problems. The show was initially hosted by Bill Slater, but the show quickly changed hosts to Martin Gabel, then left the air. Beatrice Straight appeared on at least one episode.
This show is not related in any way to a 15-minute syndicated program of the same name that aired weekly (usually on Sundays) on local stations throughout the U.S. for about 25 years beginning in the early 1970s. The latter program was a Roman Catholic-produced show concerning the church's doctrinal and moral positions on marriage and family life, and was produced at WJBK-TV in Detroit.
See also
List of programs broadcast by the DuMont Television Network
List of surviving DuMont Television Network broadcasts
References
Bibliography
David Weinstein, The Forgotten Network: DuMont and the Birth of American Television (Philadelphia: Temple University Press, 2004)
Alex McNeil, Total Television, Fourth edition (New York: Penguin Books, 1980)
Tim Brooks and Earle Marsh, The Complete Directory to Prime Time Network TV Shows, Third edition (New York: Ballantine Books, 1964)
External links
With This Ring at IMDB
DuMont historical website
DuMont Television Network original programming
1950s American game shows
1951 American television series debuts
1951 American television series endings
Black-and-white American television shows
Lost television shows |
https://en.wikipedia.org/wiki/Winsock | In computing, the Windows Sockets API (WSA), later shortened to Winsock, is an application programming interface (API) that defines how Windows network application software should access network services, especially TCP/IP. It defines a standard interface between a Windows TCP/IP client application (such as an FTP client or a web browser) and the underlying TCP/IP protocol stack. The nomenclature is based on the Berkeley sockets API used in BSD for communications between programs.
Background
Early Microsoft operating systems, both MS-DOS and Microsoft Windows, offered limited networking capability, chiefly based on NetBIOS. In particular, Microsoft did not offer support for the TCP/IP protocol stack at that time. A number of university groups and commercial vendors, including the PC/IP group at MIT, FTP Software, Sun Microsystems, Ungermann-Bass, and Excelan, introduced TCP/IP products for MS-DOS, often as part of a hardware/software bundle. When Windows 2.0 was released, these vendors were joined by others such as Distinct and NetManage in offering TCP/IP for Windows.
The drawback faced by all of these vendors was that each of them used their own API (Application Programming Interface). Without a single standard programming model, it was difficult to persuade independent software developers to create networking applications which would work with any vendor's underlying TCP/IP implementation. Add to this the fact that end users were wary of getting locked into a single vendor and it became clear that some standardization was needed.
The Windows Sockets project had its origins in a Birds Of A Feather session held at Interop '91 in San Jose on October 10, 1991. It is based on socket specifications created by NetManage and which it put into public domain at this meeting. At the time the NetManage socket was the only 100% DLL based, multi-threaded product for Windows 3.0 available. The first edition of the specification was authored by Martin Hall, Mark Towfiq of Microdyne (later Sun Microsystems), Geoff Arnold of Sun Microsystems, and Henry Sanders and J Allard of Microsoft, with assistance from many others. There was some discussion about how best to address the copyright, intellectual property, and potential anti-trust issues, and consideration was given to working through the IETF or establishing a non-profit foundation. In the end, it was decided that the specification would simply be copyrighted by the five authors as (unaffiliated) individuals.
All the participating developers resisted the shortening of the name to simple Winsock for a long time, since there was much confusion among users between the API and the DLL library file (winsock.dll) which only exposed the common WSA interfaces to applications above it. Users would commonly believe that only making sure the DLL file was present on a system would provide full TCP/IP protocol support.
Technology
The Windows Sockets API specification defines two interfaces: the API used by applicat |
https://en.wikipedia.org/wiki/Structural%20induction | Structural induction is a proof method that is used in mathematical logic (e.g., in the proof of Łoś' theorem), computer science, graph theory, and some other mathematical fields. It is a generalization of mathematical induction over natural numbers and can be further generalized to arbitrary Noetherian induction. Structural recursion is a recursion method bearing the same relationship to structural induction as ordinary recursion bears to ordinary mathematical induction.
Structural induction is used to prove that some proposition holds for all of some sort of recursively defined structure, such as
formulas, lists, or trees. A well-founded partial order is defined on the structures ("subformula" for formulas, "sublist" for lists, and "subtree" for trees). The structural induction proof is a proof that the proposition holds for all the minimal structures and that if it holds for the immediate substructures of a certain structure , then it must hold for also. (Formally speaking, this then satisfies the premises of an axiom of well-founded induction, which asserts that these two conditions are sufficient for the proposition to hold for all .)
A structurally recursive function uses the same idea to define a recursive function: "base cases" handle each minimal structure and a rule for recursion. Structural recursion is usually proved correct by structural induction; in particularly easy cases, the inductive step is often left out. The length and ++ functions in the example below are structurally recursive.
For example, if the structures are lists, one usually introduces the partial order "<", in which whenever list is the tail of list . Under this ordering, the empty list is the unique minimal element. A structural induction proof of some proposition then consists of two parts: A proof that is true and a proof that if is true for some list , and if is the tail of list , then must also be true.
Eventually, there may exist more than one base case and/or more than one inductive case, depending on how the function or structure was constructed. In those cases, a structural induction proof of some proposition then consists of:
Examples
An ancestor tree is a commonly known data structure, showing the parents, grandparents, etc. of a person as far as known (see picture for an example). It is recursively defined:
in the simplest case, an ancestor tree shows just one person (if nothing is known about their parents);
alternatively, an ancestor tree shows one person and, connected by branches, the two ancestor subtrees of their parents (using for brevity of proof the simplifying assumption that if one of them is known, both are).
As an example, the property "An ancestor tree extending over generations shows at most persons" can be proven by structural induction as follows:
In the simplest case, the tree shows just one person and hence one generation; the property is true for such a tree, since .
Alternatively, the tree shows on |
https://en.wikipedia.org/wiki/3DNow%21 | 3DNow! is a deprecated extension to the x86 instruction set developed by Advanced Micro Devices (AMD). It adds single instruction multiple data (SIMD) instructions to the base x86 instruction set, enabling it to perform vector processing of floating-point vector operations using vector registers, which improves the performance of many graphics-intensive applications. The first microprocessor to implement 3DNow! was the AMD K6-2, which was introduced in 1998. When the application was appropriate, this raised the speed by about 2–4 times.
However, the instruction set never gained much popularity, and AMD announced in August 2010 that support for 3DNow! would be dropped in future AMD processors, except for two instructions (the PREFETCH and PREFETCHW instructions). These two instructions are also available in Bay-Trail Intel processors.
History
3DNow! was developed at a time when 3D graphics were becoming mainstream in PC multimedia and games. Realtime display of 3D graphics depended heavily on the host CPU's floating-point unit (FPU) to perform floating-point calculations, a task in which AMD's K6 processor was easily outperformed by its competitor, the Intel Pentium II.
As an enhancement to the MMX instruction set, the 3DNow! instruction-set augmented the MMX SIMD registers to support common arithmetic operations (add/subtract/multiply) on single-precision (32-bit) floating-point data. Software written to use AMD's 3DNow! instead of the slower x87 FPU could execute up to four times faster, depending on the instruction mix.
Versions
3DNow!
The first implementation of 3DNow! technology contains 21 new instructions that support SIMD floating-point operations. The 3DNow! data format is packed, single-precision, floating-point. The 3DNow! instruction set also includes operations for SIMD integer operations, data prefetch, and faster MMX-to-floating-point switching. Later, Intel would add similar (but incompatible) instructions to the Pentium III, known as SSE (Streaming SIMD Extensions).
3DNow! floating-point instructions are the following:
PI2FD Packed 32-bit integer to floating-point conversion
PF2ID Packed floating-point to 32-bit integer conversion
PFCMPGE Packed floating-point comparison, greater or equal
PFCMPGT Packed floating-point comparison, greater
PFCMPEQ Packed floating-point comparison, equal
PFACC Packed floating-point accumulate
PFADD Packed floating-point addition
PFSUB Packed floating-point subtraction
PFSUBR Packed floating-point reverse subtraction
PFMIN Packed floating-point minimum
PFMAX Packed floating-point maximum
PFMUL Packed floating-point multiplication
PFRCP Packed floating-point reciprocal approximation
PFRSQRT Packed floating-point reciprocal square root approximation
PFRCPIT1 Packed floating-point reciprocal, first iteration step
PFRSQIT1 Packed floating-point reciprocal square root, first iteration step
PFRCPIT2 Packed floating-point reciprocal/reciprocal square root, second iteration step
3D |
https://en.wikipedia.org/wiki/Instructions%20per%20cycle | In computer architecture, instructions per cycle (IPC), commonly called instructions per clock, is one aspect of a processor's performance: the average number of instructions executed for each clock cycle. It is the multiplicative inverse of cycles per instruction.
Explanation
While early generations of CPUs carried out all the steps to execute an instruction sequentially, modern CPUs can do many things in parallel. As it is impossible to just keep doubling the speed of the clock, instruction pipelining and superscalar processor design have evolved so CPUs can use a variety of execution units in parallel - looking ahead through the incoming instructions in order to optimise them. This leads to the instructions per cycle completed being much higher than 1 and is responsible for much of the speed improvements in subsequent CPU generations.
Calculation of IPC
The calculation of IPC is done through running a set piece of code, calculating the number of machine-level instructions required to complete it, then using high-performance timers to calculate the number of clock cycles required to complete it on the actual hardware. The final result comes from dividing the number of instructions by the number of CPU clock cycles.
The number of instructions per second and floating point operations per second for a processor can be derived by multiplying the number of instructions per cycle with the clock rate (cycles per second given in Hertz) of the processor in question. The number of instructions per second is an approximate indicator of the likely performance of the processor.
The number of instructions executed per clock is not a constant for a given processor; it depends on how the particular software being run interacts with the processor, and indeed the entire machine, particularly the memory hierarchy. However, certain processor features tend to lead to designs that have higher-than-average IPC values; the presence of multiple arithmetic logic units (an ALU is a processor subsystem that can perform elementary arithmetic and logical operations), and short pipelines. When comparing different instruction sets, a simpler instruction set may lead to a higher IPC figure than an implementation of a more complex instruction set using the same chip technology; however, the more complex instruction set may be able to achieve more useful work with fewer instructions. As such comparing IPC figures between different instruction sets (for example x86 vs ARM) is usually meaningless.
Factors governing IPC
A given level of instructions per second can be achieved with a high IPC and a low clock speed (like the AMD Athlon and early Intel's Core Series), or from a low IPC and high clock speed (like the Intel Pentium 4 and to a lesser extent the AMD Bulldozer). Both are valid processor designs, and the choice between the two is often dictated by history, engineering constraints, or marketing pressures. However, a high IPC with a high frequency will always g |
https://en.wikipedia.org/wiki/Shugart%20Associates | Shugart Associates (later Shugart Corporation) was a computer peripheral manufacturer that dominated the floppy disk drive market in the late 1970s and is famous for introducing the -inch "Minifloppy" floppy disk drive. In 1979 it was one of the first companies to introduce a hard disk drive form factor compatible with a floppy disk drive, the SA1000 form factor compatible with the 8-inch floppy drive form factor.
Founded in 1973, Shugart Associates was purchased in 1977 by Xerox, which then exited the business in 1985 and 1986, selling the brand name and the 8-inch floppy product line (in March 1986) to Narlinger Group, which ultimately ceased operations circa 1991.
History
Beginnings
Alan Shugart, after a distinguished career at IBM and a few years at Memorex, decided to strike out on his own in 1973; after gathering venture capital, he started Shugart Associates. The original business plan was to build a small-business system (similar to the IBM 3740) dealing with the development of various major components, including floppy disk drives and printers. After two years, Shugart had exhausted his startup money and had no product to show for it. The board then wanted to focus on the floppy disk drive, but Shugart wished to continue the original plan. Official company documents state that Shugart quit, but he himself claims that he was fired by the venture capitalists. Shugart went on with Finis Conner to found Shugart Technology in 1979, which was later renamed to Seagate Technology in response to a legal challenge by Xerox.
The -inch floppy disk drive was introduced by Shugart in September 1976 as the Shugart SA-400 Minifloppy (Shugart's trademarked brand name) at an OEM price of $390 for the drive and $45 for ten diskettes. The SA-400 and related models became the company's best selling products, with shipments of up to 4000 drives per day.
The original SA-400 was single-sided with 35-tracks and used FM (single density) recording. It could be used on either hard- or soft-sector floppy controllers and was specified at 80.6 kB with a soft sectored controller. The drive became the basis of the disk system on the Radio Shack TRS-80 Model I, Apple II, and many other early microcomputers.
Late 1970s
Xerox announced acquisition of Shugart Associates in August 1977 and completed its purchase that December at a price of about $41 million.
The 440 kilobyte SA450, a double sided double density 5¼-inch full height floppy disk drive was announced in December 1977 at $450.
In 1979, Shugart Associates introduced the "Shugart Associates System Interface" (SASI) to the computing world; the interface subsequently evolved into SCSI (Small Computer System Interface). The first standard process completed in 1986 with ANSI standard X3.131-1986 (popularly known as SCSI-1) as the result. Larry Boucher led the SASI engineering team; he and several of the engineers who worked on SASI left in 1981 to found host adapter maker Adaptec.
Also in 1979, Shugart Associat |
https://en.wikipedia.org/wiki/Permit%20to%20travel | In the ticketing system of the British rail network, a Permit to Travel provisionally allows passengers to travel on a train when they have not purchased a ticket in advance and the ticket office of the station they are travelling from is closed, without incurring a penalty fare.
Because some rail passengers may travel without having their tickets checked at any point of their journey, particularly at off-peak times when stations are less likely to be staffed, the obligation to possess a Permit to Travel allows the collection of at least some revenue from passengers who would otherwise travel for free. Most train operating companies (TOCs) have altered their penalty fare policies and have removed many permit to travel machines. PERTIS machines at larger stations have also in recent years given way to more sophisticated self-service ticket machines.
History
The system, known officially as PERTIS (Permit to Travel Issuing System ), was first introduced by Network SouthEast in November 1988 on the LTS route between London Fenchurch Street and Shoeburyness. The machines, which closely resemble those found in pay and display car parks, were manufactured by Almex Control Systems. Machines were given the designation AS-9 (wall-mounted) or AS-88 (mounted on a metal base), but internal workings and tickets were identical in each case.
Penalty fare schemes spread across Network SouthEast in subsequent years, with AS-88 machines being used exclusively. Railway stations in the West Midlands and West Yorkshire passenger transport executive areas subsequently had schemes put in place, and machines were installed accordingly.
Use and operation
The front panel of the machine has two LCD displays; one shows the current time, while the other displays the amount paid when coins have been fed in. A button is pressed to print the permit, which shows a serial number, the station name, the date and time. The passenger is supposed to insert coins as near to the value of the fare as possible (if they know the fare and have enough coins), and some machines have a list of common local single and return fares.
Permits to travel bear the warning that they are not fare tickets and must be exchanged for one at the first opportunity. The record of the station of issue means that passengers who travel using it cannot claim that they just boarded the train (allowing them to travel on a cheaper fare) if they are not reached by a ticket inspector until a few stops after boarding. Permits to travel are in any case valid for only two hours from the time shown on them.
If holders of a permit to travel are asked to present their ticket by an inspector, they will be asked where they are travelling to and issued with the appropriate ticket and will be charged the difference between the balance already paid, as stated on the permit and the full cost of the ticket for their journey. If they have already paid the full price of the ticket, it will be exchanged for the permit and no mo |
https://en.wikipedia.org/wiki/Geometric%20primitive | In vector computer graphics, CAD systems, and geographic information systems, geometric primitive (or prim) is the simplest (i.e. 'atomic' or irreducible) geometric shape that the system can handle (draw, store). Sometimes the subroutines that draw the corresponding objects are called "geometric primitives" as well. The most "primitive" primitives are point and straight line segment, which were all that early vector graphics systems had.
In constructive solid geometry, primitives are simple geometric shapes such as a cube, cylinder, sphere, cone, pyramid, torus.
Modern 2D computer graphics systems may operate with primitives which are curves (segments of straight lines, circles and more complicated curves), as well as shapes (boxes, arbitrary polygons, circles).
A common set of two-dimensional primitives includes lines, points, and polygons, although some people prefer to consider triangles primitives, because every polygon can be constructed from triangles. All other graphic elements are built up from these primitives. In three dimensions, triangles or polygons positioned in three-dimensional space can be used as primitives to model more complex 3D forms. In some cases, curves (such as Bézier curves, circles, etc.) may be considered primitives; in other cases, curves are complex forms created from many straight, primitive shapes.
Common primitives
The set of geometric primitives is based on the dimension of the region being represented:
Point (0-dimensional), a single location with no height, width, or depth.
Line or curve (1-dimensional), having length but no width, although a linear feature may curve through a higher-dimensional space.
Planar surface or curved surface (2-dimensional), having length and width.
Volumetric region or solid (3-dimensional), having length, width, and depth.
In GIS, the terrain surface is often spoken of colloquially as "2 1/2 dimensional," because only the upper surface needs to be represented. Thus, elevation can be conceptualized as a scalar field property or function of two-dimensional space, affording it a number of data modeling efficiencies over true 3-dimensional objects.
A shape of any of these dimensions greater than zero consists of an infinite number of distinct points. Because digital systems are finite, only a sample set of the points in a shape can be stored. Thus, vector data structures typically represent geometric primitives using a strategic sample, organized in structures that facilitate the software interpolating the remainder of the shape at the time of analysis or display, using the algorithms of Computational geometry.
A Point is a single coordinate in a Cartesian coordinate system. Some data models allow for Multipoint features consisting of several disconnected points.
A Polygonal chain or Polyline is an ordered list of points (termed vertices in this context). The software is expected to interpolate the intervening shape of the line between adjacent points in the list as a par |
https://en.wikipedia.org/wiki/Enumeration | An enumeration is a complete, ordered listing of all the items in a collection. The term is commonly used in mathematics and computer science to refer to a listing of all of the elements of a set. The precise requirements for an enumeration (for example, whether the set must be finite, or whether the list is allowed to contain repetitions) depend on the discipline of study and the context of a given problem.
Some sets can be enumerated by means of a natural ordering (such as 1, 2, 3, 4, ... for the set of positive integers), but in other cases it may be necessary to impose a (perhaps arbitrary) ordering. In some contexts, such as enumerative combinatorics, the term enumeration is used more in the sense of counting – with emphasis on determination of the number of elements that a set contains, rather than the production of an explicit listing of those elements.
Combinatorics
In combinatorics, enumeration means counting, i.e., determining the exact number of elements of finite sets, usually grouped into infinite families, such as the family of sets each consisting of all permutations of some finite set. There are flourishing subareas in many branches of mathematics concerned with enumerating in this sense objects of special kinds. For instance, in partition enumeration and graph enumeration the objective is to count partitions or graphs that meet certain conditions.
Set theory
In set theory, the notion of enumeration has a broader sense, and does not require the set being enumerated to be finite.
Listing
When an enumeration is used in an ordered list context, we impose some sort of ordering structure requirement on the index set. While we can make the requirements on the ordering quite lax in order to allow for great generality, the most natural and common prerequisite is that the index set be well-ordered. According to this characterization, an ordered enumeration is defined to be a surjection (an onto relationship) with a well-ordered domain. This definition is natural in the sense that a given well-ordering on the index set provides a unique way to list the next element given a partial enumeration.
Countable vs. uncountable
Unless otherwise specified, an enumeration is done by means of natural numbers. That is, an enumeration of a set is a bijective function from the natural numbers or an initial segment of the natural numbers to .
A set is countable if it can be enumerated, that is, if there exists an enumeration of it. Otherwise, it is uncountable. For example, the set of the real numbers is uncountable.
A set is finite if it can be enumerated by means of a proper initial segment of the natural numbers, in which case, its cardinality is . The empty set is finite, as it can be enumerated by means of the empty initial segment of the natural numbers.
The term set is sometimes used for countable sets. However it is also often used for computably enumerable sets, which are the countable sets for which an enumeration function can |
https://en.wikipedia.org/wiki/Time%20Sharing%20Option | Time Sharing Option (TSO) is an interactive time-sharing environment for IBM mainframe operating systems, including OS/360 MVT, OS/VS2 (SVS), MVS, OS/390, and z/OS.
Use
In computing, time-sharing is a design technique that allows many people to use a computer system concurrently and independently—without interfering with each other. Each TSO user is isolated; it appears to each one that they are the only user of the system.
TSO is most commonly used by mainframe system administrators and programmers. It provides:
A text editor
Batch job support, including completion notification
Debuggers for some programming languages used on System/360 and later IBM mainframes
Support for other vendors' end-user applications, for example for querying IMS and DB2 databases
TSO interacts with users in either a line-by-line mode or in a full screen, menu-driven mode. In the line-by-line mode, the user enters commands by typing them in at the keyboard; in turn, the system interprets the commands, and then displays responses on the terminal screen. But most mainframe interaction is actually via ISPF, which allows for customized menu-driven interaction. This combination is called TSO/ISPF. TSO can also provide a Unix-style environment on OS/390 and z/OS via the UNIX System Services command shell, with or without ISPF.
TSO commands can be embedded in REXX execs or CLISTs, which can run interactively or in batch.
TSO eliminated the need to punch cards on a keypunch machine, and send card decks to the computer room to be read by a card reading machine.
History
When it was originally introduced in 1971, IBM considered time-sharing an "optional feature", as compared to standard batch processing, and hence offered TSO as an option for OS/360 MVT. With the introduction of MVS in 1974, IBM made it a standard component of their top-end mainframe operating system. TSO/E ("Time Sharing Option/Extensions") is a set of extensions to the original TSO. TSO/E is a base element of z/OS. Before z/OS, TSO Extensions (TSO/E) was an element of OS/390 and was a licensed program for the MVS and MVS/ESA System Products. Since all z/OS installations usually have both TSO and TSO/E functions installed, it is normal to refer to both TSO and TSO/E as "TSO".
When first released, TSO module names always had the "prefix" IKJ, plus the second and third letters of the associated pre-TSO functional group (IEA = original functional group of "supervisor", hence a TSO module name of IKJEAxxx, IEB = original functional group of "dataset utilities", hence a TSO module name of IKJEBxxx, etc.).
Batch use
It is common to run TSO in batch (as opposed to interactively): all the usual TSO line-mode interactive commands can be also executed via Job Control Language (JCL) by running any of the programs IKJEFT01, IKJEFT1A, and IKJEFT1B and supplying the line commands in a file pointed to by the SYSTSIN DD. The primary difference between the three programs is their handling of return codes from the e |
https://en.wikipedia.org/wiki/Radiant | Radiant may refer to:
Computers, software, and video games
Radiant (software), a content management system
GtkRadiant, a level editor created by id Software for their games
Radiant AI, a technology developed by Bethesda Softworks for The Elder Scrolls games
Radiant, the team that opposes Dire on Dota 2
Music
Radiant (Atlantic Starr album), 1981
Radiant (Iris album), 2014
Ships
HMS Radiant (1916), a destroyer of the British Royal Navy launched in 1916 and sold in 1920
USS Radiant, the name of more than one United States Navy ship
Radiant (yacht), a 2009 Lürssen built yacht
Others
Radiant heat, or thermal radiation, electromagnetic radiation emitted from the surface of an object which is due to the object's temperature
Radiant heating, a technology for heating indoor and outdoor areas
Radiant (Kitchen manufacturer), an Australian manufacturer of products for kitchens and laundries
Radiant (Magic: The Gathering), an archangel in the Magic: The Gathering trading card game
Radiant (meteor shower), the apparent origin point of meteors in a meteor shower
Radiant (novel), a 2004 science fiction novel by James Alan Gardner
Radiant (manfra), a French manfra series by Tony Valente
Radiant (typeface), a sans-serif typeface
Radiant, a diamond cut
Radiant, a line of feminine hygiene products by Procter & Gamble
Radiant Towers, a private housing estate in Tseung Kwan O, Hong Kong
See also
Radiance (disambiguation)
Radian (disambiguation)
Ray (optics)
Radio, the combining form of radiant |
https://en.wikipedia.org/wiki/United%20Way | United Way is an international network of over 1,800 local nonprofit fundraising affiliates. United Way was the largest nonprofit organization in the United States by donations from the public, prior to 2016.
United Way organizations raise funds primarily via workplace campaigns, where employers solicit contributions that can be paid through automatic payroll deductions. After an administrative fee is deducted, money raised by local United Ways is distributed to local nonprofit agencies. Major recipients have included the American Cancer Society, Big Brothers/Big Sisters, Catholic Charities, Girl Scouts, Boy Scouts, and The Salvation Army.
United Way Worldwide
Membership in United Way and use of the United Way brand is overseen by the United Way Worldwide umbrella organization. United Way Worldwide is not a top-down organization that has ownership of local United Ways. Instead, each local United Way is run as independently and incorporated separately as a 501(c)(3) organization. Each affiliate is led by local staff and volunteers and have their own board of directors, independent of United Way Worldwide or a parent organization. Some United Way affiliates, like the Central Community Chest of Japan, choose not to use the United Way name and branding.
Local United Ways pay membership dues to United Way Worldwide for licensing rights to the United Way brand and must meet criteria to maintain their membership status (including independent review boards, audits, and restrictions on marketing tactics). The membership dues to United Way Worldwide are a portion of the total funds raised by each local United Way. U.S. affiliates pay a membership fee of 1% of their total funds raised to United Way Worldwide. The structure has been described as similar to a "global franchise operation" by Forbes.
Internally, United Ways are classified by how much funds they raise on a scale of 10 levels. Metro 1 is the highest-ranking which requires raising at least $9 million annually.
Functions
United Ways are federated fundraising bodies that mobilize a single fundraising campaign to raise money for a diverse range of nonprofits. United Ways raise funds and determine how to best distribute them.
Fundraising
United Ways raise funds primarily via company-sanctioned workplace campaigns, where the employer solicits contributions from their employees that can be paid through automatic payroll deductions (in the same way tax withholdings and insurance premiums are deducted from an employee's net pay). 57% of United Way's donations come through payroll deductions while an additional 20% from corporate donations.
United Way also administers many of the annual workplace campaigns for federal employees in the US called the Combined Federal Campaign.
Nonprofit agencies that partner with United Way usually agree not to fundraise while the United Way campaigns are underway.
Distributing funds
Money raised by local United Ways is distributed to local nonprofit agencies a |
https://en.wikipedia.org/wiki/Boolean | Any kind of logic, function, expression, or theory based on the work of George Boole is considered Boolean.
Related to this, "Boolean" may refer to:
Boolean data type, a form of data with only two possible values (usually "true" and "false")
Boolean algebra, a logical calculus of truth values or set membership
Boolean algebra (structure), a set with operations resembling logical ones
Boolean domain, a set consisting of exactly two elements whose interpretations include false and true
Boolean circuit, a mathematical model for digital logical circuits.
Boolean expression, an expression in a programming language that produces a Boolean value when evaluated
Boolean function, a function that determines Boolean values or operators
Boolean model (probability theory), a model in stochastic geometry
Boolean network, a certain network consisting of a set of Boolean variables whose state is determined by other variables in the network
Boolean processor, a 1-bit variable computing unit
Boolean ring, a mathematical ring for which x2 = x for every element x
Boolean satisfiability problem, the problem of determining if there exists an interpretation that satisfies a given Boolean formula
Boolean prime ideal theorem, a theorem which states that ideals in a Boolean algebra can be extended to prime ideals
See also
Binary (disambiguation)
Broad-concept articles
Computer science |
https://en.wikipedia.org/wiki/Media%20coverage%20of%20the%20Iraq%20War | The 2003 invasion of Iraq involved unprecedented U.S. media coverage, especially cable news networks.
U.S. mainstream media coverage
The most popular cable network in the United States for news on the war was Fox News, and had begun influencing other media outlets' coverage. At the time, Fox News was owned by Rupert Murdoch, a strong supporter of the war. On-screen during all live war coverage by Fox News was a waving flag animation in the upper left corner and the headline "Operation Iraqi Freedom" along the bottom. The network has shown the American flag animation in the upper-left corner since the September 11 attacks. A study conducted in 2003 by Fairness & Accuracy in Reporting (FAIR) tracking the frequencies of pro-war and antiwar commentators on the major networks found that pro-war views were overwhelmingly more frequent. The FAIR study found that the two networks notably least likely to present critical commentary were Fox and CBS.
Anti-war celebrities appearing frequently on news networks included actors Janeane Garofalo, Tim Robbins, Mike Farrell, Rob Reiner, Martin Sheen, Susan Sarandon and director Michael Moore. In a widely publicized story, the country music band Dixie Chicks ignited boycotts and record burnings in the U.S. for their negative remarks about President Bush in a concert in London.
MSNBC also brought the American flag back on screen and regularly ran a tribute called "America's Bravest" which showed photographs sent by family members of troops deployed in Iraq. MSNBC also fired liberal Phil Donahue, a critic of Bush's Iraq policy, a month before the invasion began and replaced his show with an expanded Countdown: Iraq, initially hosted by Lester Holt. Shortly after Donahue's firing, MSNBC hired Michael Savage, a controversial conservative radio talk show host for a Saturday afternoon show. Although Donahue's show had lower ratings than several shows on other networks, and most reports on its cancellation blamed poor ratings, it was the highest-rated program on MSNBC's struggling primetime lineup at the time of its cancellation. In September 2002, Donahue's show averaged 365,000 viewers, compared to rival Connie Chung's 686,000 on CNN and Bill O'Reilly's 2 million on Fox News, according to Nielsen Media Research.
In overall numbers, Fox News was number one, followed by CNN, and then MSNBC. It was a major success for Fox News, as many had believed CNN would reclaim the top spot, since it established itself with coverage from the 1990-1991 Gulf War.
In separate incidents, at least three different Western reporters were fired or disciplined due to their actions in covering the war. Peter Arnett, an NBC and National Geographic correspondent, was fired for giving an interview with Iraqi officials in which he questioned the United States' role and saying the "first war plan had failed." Brian Walski of the Los Angeles Times was fired on March 31 for altering a photo of a British soldier warning Iraqi civilians to take c |
https://en.wikipedia.org/wiki/Transaction%20processing | In computer science, transaction processing is information processing that is divided into individual, indivisible operations called transactions. Each transaction must succeed or fail as a complete unit; it can never be only partially complete.
For example, when you purchase a book from an online bookstore, you exchange money (in the form of credit) for a book. If your credit is good, a series of related operations ensures that you get the book and the bookstore gets your money. However, if a single operation in the series fails during the exchange, the entire exchange fails. You do not get the book and the bookstore does not get your money. The technology responsible for making the exchange balanced and predictable is called transaction processing. Transactions ensure that data-oriented resources are not permanently updated unless all operations within the transactional unit complete successfully. By combining a set of related operations into a unit that either completely succeeds or completely fails, one can simplify error recovery and make one's application more reliable.
Transaction processing systems consist of computer hardware and software hosting a transaction-oriented application that performs the routine transactions necessary to conduct business. Examples include systems that manage sales order entry, airline reservations, payroll, employee records, manufacturing, and shipping.
Since most, though not necessarily all, transaction processing today is interactive, the term is often treated as synonymous with online transaction processing.
Description
Transaction processing is designed to maintain a system's Integrity (typically a database or some modern filesystems) in a known, consistent state, by ensuring that interdependent operations on the system are either all completed successfully or all canceled successfully.
For example, consider a typical banking transaction that involves moving $700 from a customer's savings account to a customer's checking account. This transaction involves at least two separate operations in computer terms: debiting the savings account by $700, and crediting the checking account by $700. If one operation succeeds but the other does not, the books of the bank will not balance at the end of the day. There must, therefore, be a way to ensure that either both operations succeed or both fail so that there is never any inconsistency in the bank's database as a whole.
Transaction processing links multiple individual operations in a single, indivisible transaction, and ensures that either all operations in a transaction are completed without error, or none of them are. If some of the operations are completed but errors occur when the others are attempted, the transaction-processing system "rolls back" all of the operations of the transaction (including the successful ones), thereby erasing all traces of the transaction and restoring the system to the consistent, known state that it was in before processin |
https://en.wikipedia.org/wiki/Pwd | In Unix-like and some other operating systems, the pwd command (print working directory) writes the full pathname of the current working directory to the standard output.
Implementations
Multics had a pwd command (which was a short name of the print_wdir command) from which the Unix pwd command originated. The command is a shell builtin in most Unix shells such as Bourne shell, ash, bash, ksh, and zsh. It can be implemented easily with the POSIX C functions getcwd() or getwd().
It is also available in the operating systems SpartaDOS X, PANOS, and KolibriOS. The equivalent on DOS (COMMAND.COM) and Microsoft Windows (cmd.exe) is the cd command with no arguments. Windows PowerShell provides the equivalent Get-Location cmdlet with the standard aliases gl and pwd.
On Windows CE 5.0, the cmd.exe Command Processor Shell includes the pwd command.
as found on Unix systems is part of the X/Open Portability Guide since issue 2 of 1987. It was inherited into the first version of POSIX.1 and the Single Unix Specification. It appeared in Version 5 Unix. The version of pwd bundled in GNU coreutils was written by Jim Meyering.
The numerical computing environments MATLAB and GNU Octave include a pwd
function with similar functionality. The OpenVMS equivalent is show default.
*nix examples
Note: POSIX requires that the default behavior be as if the -L switch were provided.
Working directory shell variables
POSIX shells set the following environment variables while using the cd command:
OLDPWD The previous working directory (as set by the cd command).
PWD The current working directory (as set by the cd command).
See also
Breadcrumb (navigation), an alternative way of displaying the work directory
List of GNU Core Utilities commands
List of Unix commands
pushd and popd
References
Further reading
External links
Multics commands
Unix SUS2008 utilities
Plan 9 commands
Inferno (operating system) commands
IBM i Qshell commands
File system directories |
https://en.wikipedia.org/wiki/1984%20%28advertisement%29 | "1984" is an American television commercial that introduced the Apple Macintosh personal computer. It was conceived by Steve Hayden, Brent Thomas, and Lee Clow at Chiat/Day, produced by New York production company Fairbanks Films, and directed by Ridley Scott. The ad was an allusion to George Orwell's noted 1949 novel, Nineteen Eighty-Four, which described a dystopian future ruled by a televised "Big Brother". English athlete Anya Major performed as the unnamed heroine and David Graham as Big Brother. In the US, it first aired in 10 local outlets, including Twin Falls, Idaho, where Chiat/Day ran the ad on December 31, 1983, at the last possible break before midnight on KMVT, so that the advertisement qualified for the 1984 Clio Awards. Its second televised airing, and only US national airing, was on January 22, 1984, during a break in the third quarter of the telecast of Super Bowl XVIII by CBS.
In one interpretation of the commercial, "1984" used the unnamed heroine to represent the coming of the Macintosh (indicated by her white tank top with a stylized line drawing of Apple’s Macintosh computer on it) as a means of saving humanity from "conformity" (Big Brother).
Originally a subject of contention within Apple, it has subsequently been called a watershed event and a masterpiece in advertising. In 1995, The Clio Awards added it to its Hall of Fame, and Advertising Age placed it on the top of its list of 50 greatest commercials.
In January 1984, Apple also launched the inventé advertisement for Macintosh in France.
Plot
The commercial opens with a dystopian, industrial setting in blue and grayish tones, showing a line of people marching in unison through a long tunnel monitored by a string of telescreens. This is in sharp contrast to the full-color shots of the nameless runner (Anya Major). She looks like a competitive track and field athlete, wearing an athletic "uniform" (red athletic shorts, running shoes, a white tank top with a cubist picture of Apple's Macintosh computer, a white sweat band on her left wrist, and a red one on her right), and is carrying a large brass-headed sledgehammer. Rows of marching minions evoke the opening scenes of Metropolis.
As she is chased by four police officers (presumably agents of the Thought Police) wearing black uniforms, protected by riot gear, helmets with visors covering their faces, and armed with large night sticks, she races towards a large screen with the image of a Big Brother-like figure (David Graham, also seen on the telescreens earlier) giving a speech:
The runner, now close to the screen, hurls the hammer towards it, right at the moment Big Brother announces, “we shall prevail!” In a flurry of light and smoke, the screen is destroyed, leaving the audience in shock.
The commercial concludes with a portentous voiceover by actor Edward Grover, accompanied by scrolling black text (in Apple's early signature "Garamond" typeface); the hazy, whitish-blue aftermath of the cataclysmic even |
https://en.wikipedia.org/wiki/Memory%20card | A memory card is an electronic data storage device used for storing digital information, typically using flash memory. These are commonly used in digital portable electronic devices. They allow adding memory to such devices using a card in a socket instead of protruding USB flash drives.
History
The basis for memory card technology is flash memory. It was invented by Fujio Masuoka at Toshiba in 1980 and commercialized by Toshiba in 1987.
PC Cards (PCMCIA) were the first commercial memory card formats (type I cards) to come out, but are now mainly used in industrial applications and to connect I/O devices such as modems. In 1992, SanDisk introduced FlashDisk, a PCMCIA card and one of the first memory cards that did not require battery power to retain its contents. Since 1994, a number of memory card formats smaller than the PC Card arrived. The first one was CompactFlash and later SmartMedia and Miniature Card. The desire for smaller cards for cell-phones, PDAs, and compact digital cameras drove a trend that left the previous generation of "compact" cards looking big. In 2001, SM alone captured 50% of the digital camera market and CF had captured the professional digital camera market. By 2005 however, SD/MMC had nearly taken over SmartMedia's spot, though not to the same level and with stiff competition coming from Memory Stick variants, as well as CompactFlash. In industrial and embedded fields, even the venerable PC card (PCMCIA) memory cards still manage to maintain a niche, while in mobile phones and PDAs, the memory card has become smaller.
Initially memory cards were expensive, costing US$3 per megabyte of capacity in 2001; this led to the development of miniaturized rotating magnetic disk memory devices such as the Microdrive, PocketZip and Dataplay. All three concepts became obsolete once flash memory prices became lower and their capacities became higher by 2006.
Since 2010, new products of Sony (previously only using Memory Stick) and Olympus (previously only using XD-Card) have been offered with an additional SD-Card slot. Effectively the format war has turned in SD-Card's favor.
Data table of selected memory card formats
Overview of all memory card types
PCMCIA ATA Type I Card (PC Card ATA Type I)
PCMCIA Type II, Type III cards
CompactFlash Card (Type I), CompactFlash High-Speed
CompactFlash Type II, CF+(CF2.0), CF3.0
Microdrive
CFexpress
MiniCard (Miniature Card) (max 64 MB / 64 MiB)
SmartMedia Card (SSFDC) (max 128 MB) (3.3 V,5 V)
xD-Picture Card, xD-Picture Card Type M
Memory Stick, MagicGate Memory Stick (max 128 MB); Memory Stick Select, MagicGate Memory Stick Select ("Select" means: 2x128 MB with A/B switch)
SecureMMC
Secure Digital (SD Card), Secure Digital High-Speed, Secure Digital Plus/Xtra/etc (SD with USB connector)
miniSD card
microSD card (aka Transflash, T-Flash, TF)
SDHC
WiFi SD Cards (SD Card With WiFi Card Built in) Powered by Device. (Eye-Fi, WiFi SD, Flash Air)
Nano Memory (NM) card
MU-Flash (Mu-Card) (Mu |
https://en.wikipedia.org/wiki/Order%20of%20operations | In mathematics and computer programming, the order of operations is a collection of rules that reflect conventions about which operations to perform first in order to evaluate a given mathematical expression.
These rules are formalized with a ranking of the operators. The rank of an operator is called its precedence, and an operation with a higher precedence is performed before operations with lower precedence. Calculators generally perform operations with the same precedence from left to right, but some programming languages and calculators adopt different conventions.
For example, multiplication is granted a higher precedence than addition, and it has been this way since the introduction of modern algebraic notation. Thus, in the expression , the multiplication is performed before addition, and the expression has the value , and not . When exponents were introduced in the 16th and 17th centuries, they were given precedence over both addition and multiplication and placed as a superscript to the right of their base. Thus and .
These conventions exist to avoid notational ambiguity while allowing notation to remain brief. Where it is desired to override the precedence conventions, or even simply to emphasize them, parentheses ( ) can be used. For example, forces addition to precede multiplication, while forces addition to precede exponentiation. If multiple pairs of parentheses are required in a mathematical expression (such as in the case of nested parentheses), the parentheses may be replaced by brackets or braces to avoid confusion, as in .
These rules are meaningful only when the usual notation (called infix notation) is used. When functional or Polish notation are used for all operations, the order of operations results from the notation itself.
Internet memes sometimes present ambiguous infix expressions that cause disputes and increase web traffic. Most of these ambiguous expressions involve mixed division and multiplication, where there is no general agreement about the order of operations.
Definition
The order of operations, that is, the order in which the operations in an expression are usually performed, results from a convention adopted throughout mathematics, science, technology and many computer programming languages. It is summarized as:
Parentheses
Exponentiation
Multiplication and Division
Addition and Subtraction
This means that to evaluate an expression, one first evaluates any sub-expression inside parentheses, working inside to outside if there is more than one set. Whether inside parenthesis or not, the operator that is higher in the above list should be applied first.
The commutative and associative laws of addition and multiplication allow adding terms in any order, and multiplying factors in any order—but mixed operations obey the standard order of operations.
In some contexts, it is helpful to replace a division with multiplication by the reciprocal (multiplicative inverse) and a subtraction by addition |
https://en.wikipedia.org/wiki/Early%20stopping | In machine learning, early stopping is a form of regularization used to avoid overfitting when training a learner with an iterative method, such as gradient descent. Such methods update the learner so as to make it better fit the training data with each iteration. Up to a point, this improves the learner's performance on data outside of the training set. Past that point, however, improving the learner's fit to the training data comes at the expense of increased generalization error. Early stopping rules provide guidance as to how many iterations can be run before the learner begins to over-fit. Early stopping rules have been employed in many different machine learning methods, with varying amounts of theoretical foundation.
Background
This section presents some of the basic machine-learning concepts required for a description of early stopping methods.
Overfitting
Machine learning algorithms train a model based on a finite set of training data. During this training, the model is evaluated based on how well it predicts the observations contained in the training set. In general, however, the goal of a machine learning scheme is to produce a model that generalizes, that is, that predicts previously unseen observations. Overfitting occurs when a model fits the data in the training set well, while incurring larger generalization error.
Regularization
Regularization, in the context of machine learning, refers to the process of modifying a learning algorithm so as to prevent overfitting. This generally involves imposing some sort of smoothness constraint on the learned model.
This smoothness may be enforced explicitly, by fixing the number of parameters in the model, or by augmenting the cost function as in Tikhonov regularization. Tikhonov regularization, along with principal component regression and many other regularization schemes, fall under the umbrella of spectral regularization, regularization characterized by the application of a filter. Early stopping also belongs to this class of methods.
Gradient descent methods
Gradient descent methods are first-order, iterative, optimization methods. Each iteration updates an approximate solution to the optimization problem by taking a step in the direction of the negative of the gradient of the objective function. By choosing the step-size appropriately, such a method can be made to converge to a local minimum of the objective function. Gradient descent is used in machine-learning by defining a loss function that reflects the error of the learner on the training set and then minimizing that function.
Early stopping based on analytical results
Early stopping in statistical learning theory
Early-stopping can be used to regularize non-parametric regression problems encountered in machine learning. For a given input space, , output space, , and samples drawn from an unknown probability measure, , on , the goal of such problems is to approximate a regression function, , given by
where is the conditi |
https://en.wikipedia.org/wiki/Eldon%20C.%20Hall | Eldon Hall was the leader of hardware design efforts for the Apollo Guidance Computer (AGC) at MIT, and advocated the use of integrated circuits for this task. He wrote extensively of the development of the AGC, culminating in his 1996 book, Journey to the Moon: The History of the Apollo Guidance Computer ()
He pursued his undergraduate education at the Eastern Nazarene College in Quincy, Massachusetts, his graduate education at Boston University, and his doctoral degree at Harvard University (though he did not complete the PhD).
Awards
1997: Stibitz-Wilson Award from the American Computer & Robotics Museum
Publications
Eldon C. Hall (2000). From the Farm to Pioneering with Digital Computers: An Autobiography.
Eldon C. Hall (1996). Journey to the Moon: The History of the Apollo Guidance Computer
References
1923 births
2022 deaths
Massachusetts Institute of Technology faculty
American computer scientists
American technology writers
Eastern Nazarene College alumni
Harvard University alumni
Boston University alumni
People from Payette, Idaho |
https://en.wikipedia.org/wiki/Subtyping | In programming language theory, subtyping (also called subtype polymorphism or inclusion polymorphism) is a form of type polymorphism. A subtype is a datatype that is related to another datatype (the supertype) by some notion of substitutability, meaning that program elements (typically subroutines or functions), written to operate on elements of the supertype, can also operate on elements of the subtype.
If S is a subtype of T, the subtyping relation (written as , , or ) means that any term of type S can safely be used in any context where a term of type T is expected. The precise semantics of subtyping here crucially depends on the particulars of how "safely be used" and "any context" are defined by a given type formalism or programming language. The type system of a programming language essentially defines its own subtyping relation, which may well be trivial, should the language support no (or very little) conversion mechanisms.
Due to the subtyping relation, a term may belong to more than one type. Subtyping is therefore a form of type polymorphism. In object-oriented programming the term 'polymorphism' is commonly used to refer solely to this subtype polymorphism, while the techniques of parametric polymorphism would be considered generic programming.
Functional programming languages often allow the subtyping of records. Consequently, simply typed lambda calculus extended with record types is perhaps the simplest theoretical setting in which a useful notion of subtyping may be defined and studied. Because the resulting calculus allows terms to have more than one type, it is no longer a "simple" type theory. Since functional programming languages, by definition, support function literals, which can also be stored in records, records types with subtyping provide some of the features of object-oriented programming. Typically, functional programming languages also provide some, usually restricted, form of parametric polymorphism. In a theoretical setting, it is desirable to study the interaction of the two features; a common theoretical setting is system F<:. Various calculi that attempt to capture the theoretical properties of object-oriented programming may be derived from system F<:.
The concept of subtyping is related to the linguistic notions of hyponymy and holonymy. It is also related to the concept of bounded quantification in mathematical logic (see Order-sorted logic). Subtyping should not be confused with the notion of (class or object) inheritance from object-oriented languages; subtyping is a relation between types (interfaces in object-oriented parlance) whereas inheritance is a relation between implementations stemming from a language feature that allows new objects to be created from existing ones. In a number of object-oriented languages, subtyping is called interface inheritance, with inheritance referred to as implementation inheritance.
Origins
The notion of subtyping in programming languages dates back to the 1960 |
https://en.wikipedia.org/wiki/C%C3%B4te%20d%27Azur%20Observatory | The Côte d'Azur Observatory (, OCA) is a network of astronomical observatories throughout southern France. It originated in 1988 with the merger of two observatories:
Nice Observatory
Centre de recherches en géodynamique et astrométrie (CERGA)
Cote d'Azure Observatory tested beam combining technology at CHARA array.
Astronomers developed a theory about M-Type asteroids, that may be tested by the planned spacecraft Psyche.
See also
List of astronomical observatories
Lunar Laser Ranging Experiment
OCA-DLR Asteroid Survey
References
External links
Côte d'Azur Observatory official website (English version)
Grand Interferometre a 2 Telescopes (GI2T REGAIN )
Astronomical observatories in France |
https://en.wikipedia.org/wiki/Uniform%20Crime%20Reports | The Uniform Crime Reporting (UCR) program compiles official data on crime in the United States, published by the Federal Bureau of Investigation (FBI). UCR is "a nationwide, cooperative statistical effort of nearly 18,000 city, university and college, county, state, tribal, and federal law enforcement agencies voluntarily reporting data on crimes brought to their attention".
Crime statistics are compiled from UCR data and published annually by the FBI in the Crime in the United States series. The FBI does not collect the data itself. Rather, law enforcement agencies across the United States provide the data to the FBI, which then compiles the Reports.
The Uniform Crime Reporting program began in 1929, and since then has become an important source of crime information for law enforcement, policymakers, scholars, and the media.
History
The UCR Program was based upon work by the International Association of Chiefs of Police (IACP) and the Social Science Research Council (SSRC) throughout the 1920s to create a uniform national set of crime statistics, reliable for analysis. In 1927, the IACP created the Committee on Uniform Crime Reporting to determine statistics for national comparisons. The committee determined seven crimes fundamental to comparing crime rates: murder and non-negligent manslaughter, forcible rape, burglary, aggravated assault, larceny and motor vehicle theft (the eighth, arson, was added under a congressional directive in 1979). The early program was managed by the IACP, prior to FBI involvement, done through a monthly report. The first report in January 1930 reported data from 400 cities throughout 43 states, covering more than 20 million individuals, approximately twenty percent of the total U.S. population.
On June 11, 1930, through IACP lobbying, the United States Congress passed legislation enacting 28 U.S.C. § 534, which granted the office of the Attorney General the ability to "acquire, collect, classify, and preserve identification, criminal identification, crime, and other records" with the ability to appoint officials to oversee this duty, including the subordinate members of the Bureau of Investigation. The Attorney General, in turn, designated the FBI to serve as the national clearinghouse for the data collected, and the FBI assumed responsibility for managing the UCR Program in September 1930. The July 1930 issue of the IACP crime report announced the FBI's takeover of the program. While the IACP discontinued oversight of the program, they continued to advise the FBI to better the UCR.
Since 1935, the FBI served as a data clearinghouse; organizing, collecting, and disseminating information voluntarily submitted by local, state, federal and tribal law enforcement agencies. The UCR remained the primary tool for collection and analysis of data for the next half century. Throughout the 1980s, a series of National UCR Conferences were with members from the IACP, Department of Justice, including the FBI, and ne |
https://en.wikipedia.org/wiki/ASCII%20%28magazine%29 | was a monthly released microcomputer magazine in Japan, published by ASCII Corporation from 1977. It targeted business users who used a personal computer in their home and office, but it sometimes introduced computer games and computer music. It was also known as the written along with the title from Vol. 2 No. 4, and distinguish with the founded in 1997. The ASCII was rebranded as the in 2008, and ceased in 2010. Its news website and the Weekly ASCII are continuing as in 2016.
The , a computer game magazine, was first published as an extra issue of the ASCII in 1982, and the was branched from the LOGiN.
Foundation
In 1976, NEC released the TK-80, a single-board computer kit, and it became popular among hobbyists in Japan. joined foundation of the first Japanese microcomputer magazine I/O (ja) as an editor when he was a student at the Waseda University. The I/O initially served information for assembled microcomputer systems with a few video game columns. Growing the video game market, it was shifted to a video game magazine. Against it, Nishi considered that personal computers must have far more potential than video games.
In April 1977, Nishi left the company, borrowed money from his grandmother and visited the West Coast Computer Faire held in San Francisco. Then, he realized the difference between Japan and the United States. "In Japan, the TK-80 just caused a microcomputer craze. While in the United States, it seems the beginning of the personal computer revolution. Each persons try to face a personal computer, based on their own identity," he said.
On May 24, 1977, Nishi founded with his friends, and . They published the ASCII as a microcomputer magazine for business, while the I/O was for hobbyists. The first issue was sold 5,000 copies. It became one of the most popular computer magazine in 1980s in Japan. In 1999, the magazine reached its largest circulation of 170,000 copies.
References
External links
ASCII.jp
Defunct computer magazines
Defunct magazines published in Japan
Magazines established in 1977
Magazines disestablished in 2008
Magazines published in Tokyo
Monthly magazines published in Japan |
https://en.wikipedia.org/wiki/Transport%20in%20Aruba | Transport in Aruba is facilitated by road, air, and rail. Aruba features a well-established road network, with the majority of the roads being paved. However, as one ventures towards the interior of the island, the prevalence of paved roads decreases, giving way to more rugged terrain. Conversely, coastal areas typically offer-well maintained paved roads. Aruba's road network covers a total distance of about , with remaining unpaved.
Public transport
The department of public transport, also known in as Departamento di Transporte Publico (DTP) in Papiamento or Dienst Openbaar Personen Vervoer (DOPV) in Dutch, is the government agency overseeing various modes of public transportations, including taxis, buses, tour buses, and rental vehicle, such as cars, scooters, quads, races, and motorcycles). All public transportation services are required to obtain a transportation permit through DOPV.
Buses
Arubus N.V. is the major public transportation company and is owned by the Government of Aruba. It offers transportation services across large parts of the island, operating a fleet of approximately 29 buses. Mini-buses are also a common sight. There are two primary Arubus station located in Oranjestad and San Nicolas.
As per the Central Bureau of Statistics (CBS), the number of registered buses has remained relatively stable from 2015 to 2021. In 2015, there were 129 registered buses, and this number increased to 140 by 2021. In contrast to buses, the count of registered tour buses, has experienced a rapid increase, growing from 94 to 312.
Data from the CBS indicates a decline in the total number of bus passengers (excluding school children) from 2010 to 2021. In 2010, a total of 2,719,083 passengers were transported, whereas in 2021, the number decreased to 1,129,944.
Air transport
Travelers have the option to take short plane flights from Queen Beatrix International Airport. The major local airlines, Divi Divi Air and EZ Air, operate multiple daily flights between Aruba, Curaçao, and Bonaire. However, flying between the islands can be costly, and there have been persistent challenges. Since the 1970s, at least fifteen airlines, both local and from Europe, have made attempts in this regard. Local airlines, such as Air Aruba, have faced financial issues, leading to bankruptcies over the years.
The Antilliaanse Luchtvaartmaatschappij (ALM), or Antillean Airline, held the skies for 37 years, marking its status as the longest-running airline in the region. As a government-owned entity, it enjoyed a monopoly over the islands. ALM's reach extended to 26 flight destinations, with the largest portion (five) in Venezuela. In 2001, circumstances compelled it to halt its operations.
Director Edwin Kelly of the Directie Luchtvaart Aruba, or Aruba Aviation Directorate, highlights significant challenges: insufficient considerations of market changes. Kelly point out that the Venezuelan market was robust, as was the Cuban market, but liberalization has hal |
https://en.wikipedia.org/wiki/Stateful%20firewall | In computing, a stateful firewall is a network-based firewall that individually tracks sessions of network connections traversing it. Stateful packet inspection, also referred to as dynamic packet filtering, is a security feature often used in non-commercial and business networks.
Description
A stateful firewall keeps track of the state of network connections, such as TCP streams, UDP datagrams, and ICMP messages, and can apply labels such as LISTEN, ESTABLISHED, or CLOSING. State table entries are created for TCP streams or UDP datagrams that are allowed to communicate through the firewall in accordance with the configured security policy. Once in the table, all RELATED packets of a stored session are streamlined, taking fewer CPU cycles than standard inspection. Related packets are also permitted to return through the firewall even if no rule is configured to allow communications from that host. If no traffic is seen for a specified time (time-out implementation dependent), the connection is removed from the state table. This can lead to applications experiencing unexpected disconnects or half-open TCP connections. Applications can be written to send keepalive messages periodically to prevent a firewall from dropping the connection during periods of no activity or for applications which by design have long periods of silence.
The method of maintaining a session's state depends on the transport protocol being used. TCP is a connection-oriented protocol and sessions are established with a three-way handshake using SYN packets and ended by sending a FIN notification. The firewall can use these unique connection identifiers to know when to remove a session from the state table without waiting for a timeout. UDP is a connectionless protocol, which means it does not send unique connection-related identifiers while communicating. Because of that, a session will only be removed from the state table after the configured time-out. UDP hole punching is a technology that leverages this trait to allow for dynamically setting up data tunnels over the internet. ICMP messages are distinct from TCP and UDP and communicate control information of the network itself. A well-known example of this is the ping utility. ICMP responses will be allowed back through the firewall. In some scenarios, UDP communication can use ICMP to provide information about the state of the session so ICMP responses related to a UDP session will also be allowed back through.
Stateful inspection firewall advantages
Monitors the entire session for the state of the connection, while also checking IP addresses and payloads for more thorough security
Offers a high degree of control over what content is let in or out of the network
Does not need to open numerous ports to allow traffic in or out
Delivers substantive logging capabilities
Stateful inspection firewall disadvantages
Resource-intensive and interferes with the speed of network communications
More expensive than other f |
https://en.wikipedia.org/wiki/Emergent%20algorithm | An emergent algorithm is an algorithm that exhibits emergent behavior. In essence an emergent algorithm implements a set of simple building block behaviors that when combined exhibit more complex behaviors. One example of this is the implementation of fuzzy motion controllers used to adapt robot movement in response to environmental obstacles.
An emergent algorithm has the following characteristics:
it achieves predictable global effects
it does not require global visibility
it does not assume any kind of centralized control
it is self-stabilizing
Other examples of emergent algorithms and models include cellular automata, artificial neural networks and swarm intelligence systems (ant colony optimization, bees algorithm, etc.).
See also
AI alignment
Artificial intelligence detection software
Emergence
Evolutionary computation
Fuzzy logic
Genetic algorithm
Heuristic
References
Algorithm
Heuristic algorithms
Algorithms
Artificial intelligence
Cybernetics |
https://en.wikipedia.org/wiki/Write%20protection | Write protection is any physical mechanism that prevents writing, modifying, or erasing data on a device. Most commercial software, audio and video on writeable media is write-protected when distributed.
Examples
IBM -inch magnetic tape reels, introduced in the 1950s, had a circular groove on one side of the reel, into which a soft plastic ring had to be placed in order to write on the tape. ("No ring, no write.")
Audio cassettes and VHS videocassettes have tabs on the top/rear edge that can be broken off (uncovered = protected).
8 and -inch floppies can have, respectively, write-protect and write-enable notches on the right side (8-inch punched = protected; -inch covered/notch not present = protected). A common practice with single-sided floppies was to punch a second notch on the opposite side of the disk to enable use of both sides of the media, creating a flippy disk, so called because one originally had to flip the disk over to use the other side.
-inch floppy disks have a sliding tab in a window on the right side (open = protected).
Iomega Zip disks were write-protected using the IomegaWare software.
Syquest EZ-drive (135 & 250 MB) disks were write-protected using a small metal switch on the rear of the disk at the bottom.
VHS-C, Video8, Hi8, and DV videocassettes have a sliding tab on the rear edge.
Iomega ditto tape cartridges had a small sliding tab on the top left hand corner on the front face of the cartridge.
USB flash drives sometimes have a small switch, though this has become uncommon. An example of a USB flash drive that supported write protection via a switch is the Transcend JetFlash series.
Secure Digital (SD) cards have a write-protect tab on the left side.
Extensively, media that, by means of design, can't operate outside from this mode: CD-R, DVD-R, Vinyl records, etc.
These mechanisms are intended to prevent only accidental data loss or attacks by computer viruses. A determined user can easily circumvent them either by covering a notch with adhesive tape or by creating one with a punch as appropriate, or sometimes by physically altering the media transport to ignore the write-protect mechanism.
Write-protection is typically enforced by the hardware. In the case of computer devices, attempting to violate it will return an error to the operating system while some tape recorders physically lock the record button when a write-protected cassette is present.
Write blocking
Write blocking, a subset of write protection, is a technique used in computer forensics in order to maintain the integrity of data storage devices. By preventing all write operations to the device, e.g. a hard drive, it can be ensured that the device remains unaltered by data recovery methods.
Hardware write blocking was invented by Mark Menz and Steve Bress (US patent 6,813,682 and EU patent EP1,342,145).
Both hardware and software write-blocking methods are used; however, software blocking is generally not as reliable, due to human error.
|
https://en.wikipedia.org/wiki/Stress%20testing%20%28computing%29 | In computing, stress testing (sometimes called torture testing) can be applied to either hardware or software. It is used to determine the maximum capability of a computer system and is often used for purposes such as scaling for production use and ensuring reliability and stability. Stress tests typically involve running a large amount of resource-intensive processes until the system either crashes or nearly does so.
Hardware
Software
See also
Burn-in
Destructive testing
Load and performance test tools
Black box testing
Load testing
Software performance testing
Scenario analysis
Simulation
Software testing
White box testing
Technischer Überwachungsverein (TÜV) – product testing and certification
Concurrency testing using the CHESS model checker
Jinx automates stress testing by automatically exploring unlikely execution scenarios.
Highly accelerated life test
References
Software testing
Product testing |
https://en.wikipedia.org/wiki/OBject%20EXchange | OBEX (abbreviation of OBject EXchange, also termed IrOBEX) is a communication protocol that facilitates the exchange of binary objects between devices. It is maintained by the Infrared Data Association but has also been adopted by the Bluetooth Special Interest Group and the SyncML wing of the Open Mobile Alliance (OMA). One of OBEX's earliest popular applications was in the Palm III. This PDA and its many successors use OBEX to exchange business cards, data, even applications.
Although OBEX was initially designed for infrared, it has now been adopted by Bluetooth, and is also used over RS-232, USB, WAP and in devices such as Livescribe smartpens.
Comparison to HTTP
OBEX is similar in design and function to HTTP in providing the client with a reliable transport for connecting to a server and may then request or provide objects. But OBEX differs in many important respects:
HTTP is normally layered above a TCP/IP link. OBEX can also be, but is commonly implemented on an IrLAP/IrLMP/Tiny TP stack on an IrDA device. In Bluetooth, OBEX is implemented on a Baseband/ACL/L2CAP (and, for legacy uses, RFCOMM) stack. Other such "bindings" of OBEX are possible, such as over USB.
HTTP uses human-readable text, but OBEX uses binary-formatted type–length–value triplets named "Headers" to exchange information about a request or an object. These are much easier to parse by resource-limited devices.
HTTP transactions are inherently stateless; generally an HTTP client opens a connection, makes a single request, receives its response, and either closes the connection or makes other unrelated requests. In OBEX, a single transport connection may bear many related operations. In fact, recent additions to the OBEX specification allow an abruptly closed transaction to be resumed with all state information intact.
Objects
OBEX works by exchanging objects, which are used for a variety of purposes: establishing the parameters of a connection, sending and requesting data, changing the current path or the attributes of a file.
Objects are fields and headers. As an example, the following may be the object used for requesting the phonebook from a mobile:
This object contains two fields (command and length) and two headers. The first field (command) specifies that it is a request for data (GET). The second field is the total size of the object, including the two fields.
This object also contains two headers, specifically a "Connection ID" and a "Name". The first byte of each header is the header's name and its content type. In this case:
0xCB means that this header is a "Connection ID", a number obtained previously; the two highest-order bits of 0xCB are 11, and this pair specifies that this as a 4-byte quantity;
the first byte of the second header is 0x01; this byte identifies this header as a "Name" one; the first two bits of 0x01 are 00, meaning that the content of this header is a null-terminated unicode string (in UCS-2 form), prefixed by the number of bytes it i |
https://en.wikipedia.org/wiki/Porting | In software engineering, porting is the process of adapting software for the purpose of achieving some form of execution in a computing environment that is different from the one that a given program (meant for such execution) was originally designed for (e.g., different CPU, operating system, or third party library). The term is also used when software/hardware is changed to make them usable in different environments.
Software is portable when the cost of porting it to a new platform is significantly less than the cost of writing it from scratch. The lower the cost of porting software relative to its implementation cost, the more portable it is said to be.
Etymology
The term "port" is derived from the Latin portāre, meaning "to carry". When code is not compatible with a particular operating system or architecture, the code must be "carried" to the new system.
The term is not generally applied to the process of adapting software to run with less memory on the same CPU and operating system.
Software developers often claim that the software they write is portable, meaning that little effort is needed to adapt it to a new environment. The amount of effort actually needed depends on several factors, including the extent to which the original environment (the source platform) differs from the new environment (the target platform), the experience of the original authors in knowing which programming language constructs and third party library calls are unlikely to be portable, and the amount of effort invested by the original authors in only using portable constructs (platform specific constructs often provide a cheaper solution).
History
The number of significantly different CPUs and operating systems used on the desktop today is much smaller than in the past. The dominance of the x86 architecture means that most desktop software is never ported to a different CPU. In that same market, the choice of operating systems has effectively been reduced to three: Microsoft Windows, macOS, and Linux. However, in the embedded systems and mobile markets, portability remains a significant issue, with the ARM being a widely used alternative.
International standards, such as those promulgated by the ISO, greatly facilitate porting by specifying details of the computing environment in a way that helps reduce differences between different standards-conforming platforms. Writing software that stays within the bounds specified by these standards represents a practical although nontrivial effort. Porting such a program between two standards-compliant platforms (such as POSIX.1) can be just a matter of loading the source code and recompiling it on the new platform. However, practitioners often find that various minor corrections are required, due to subtle platform differences. Most standards suffer from "gray areas" where differences in interpretation of standards lead to small variations from platform to platform.
There also exists an ever-increasing number |
https://en.wikipedia.org/wiki/Endian | Endian may refer to:
Endianness, the order of the bytes, comprising a digital word, in computer memory
Endian Firewall, a Linux distribution of the South Tyrolean company Endian
See also
Big-endians, a fictional group in Gulliver's Travels |
https://en.wikipedia.org/wiki/Automake | In software development, GNU Automake is a programming tool to automate parts of the compilation process. It eases usual compilation problems. For example, it points to needed dependencies.
It automatically generates one or more Makefile.in from files called Makefile.am. Each Makefile.am contains, among other things, useful variable definitions for the compiled software, such as compiler and linker flags, dependencies and their versions, etc. The generated "Makefile.in"s are portable and compliant with the Makefile conventions in the GNU Coding Standards, and may be used by configure scripts to generate a working Makefile.
The Free Software Foundation maintains as one of the GNU programs, and as part of the GNU build system. It is used to build several GNU applications and libraries, such as GTK, as well as non-GNU software such as XCircuit.
Process
Automake aims to allow the programmer to write a makefile in a higher-level language, rather than having to write the whole makefile manually. In simple cases, it suffices to give:
A line that declares the name of the program to build
A list of source files
A list of command-line options to be passed to the compiler (for example, in which directories header files will be found)
A list of command-line options to be passed to the linker (which libraries the program needs and in what directories they are to be found)
Automake also takes care of automatically generating the dependency information, so that when a source file is modified, the next invocation of the make command will know which source files need to be recompiled. If the compiler allows it, Automake tries to make the dependency system dynamic: whenever a source file is compiled, that file's dependencies are updated by asking the compiler to regenerate the file's dependency list. In other words, dependency tracking is a side effect of the compilation process.
This attempts to avoid the problem with some static dependency systems, where the dependencies are detected only once when the programmer starts working on the project.
Design
Automake is written in Perl and must be used with GNU Autoconf. Automake contains the following commands:
aclocal
automake
aclocal, however, is a general-purpose program that can be useful to autoconf users. The GNU Compiler Collection (GCC), for example, uses aclocal even though its makefile is hand written.
Like Autoconf, Automake is not entirely backward compatible. For example, a project created with automake 1.13 will not necessarily work with automake 1.14.
See also
configure script
Make (software)
References
Sources
External links
Online version of The Goat Book aka Autobook
Combined manual for Automake and Autoconf
Autotoolset home page
Build automation
Compiling tools
Cross-platform free software
Free software programmed in Perl
GNU Project software
Software using the GPL license |
https://en.wikipedia.org/wiki/Base64 | In computer programming, Base64 is a group of tetrasexagesimal binary-to-text encoding schemes that represent binary data (more specifically, a sequence of 8-bit bytes) in sequences of 24 bits that can be represented by four 6-bit Base64 digits.
As with all binary-to-text encoding schemes, Base64 is designed to carry data stored in binary formats across channels that only reliably support text content. Base64 is particularly prevalent on the World Wide Web where one of its uses is the ability to embed image files or other binary assets inside textual assets such as HTML and CSS files.
Base64 is also widely used for sending e-mail attachments. This is required because SMTP – in its original form – was designed to transport 7-bit ASCII characters only. This encoding causes an overhead of 33–37% (33% by the encoding itself; up to 4% more by the inserted line breaks).
Design
The particular set of 64 characters chosen to represent the 64-digit values for the base varies between implementations. The general strategy is to choose 64 characters that are common to most encodings and that are also printable. This combination leaves the data unlikely to be modified in transit through information systems, such as email, that were traditionally not 8-bit clean. For example, MIME's Base64 implementation uses A–Z, a–z, and 0–9 for the first 62 values. Other variations share this property but differ in the symbols chosen for the last two values; an example is UTF-7.
The earliest instances of this type of encoding were created for dial-up communication between systems running the same OS, for example, uuencode for UNIX and BinHex for the TRS-80 (later adapted for the Macintosh), and could therefore make more assumptions about what characters were safe to use. For instance, uuencode uses uppercase letters, digits, and many punctuation characters, but no lowercase.
Base64 table from RFC 4648
This is the Base64 alphabet defined in RFC 4648 §4 . See also Variants summary (below).
Examples
The example below uses ASCII text for simplicity, but this is not a typical use case, as it can already be safely transferred across all systems that can handle Base64. The more typical use is to encode binary data (such as an image); the resulting Base64 data will only contain 64 different ASCII characters, all of which can reliably be transferred across systems that may corrupt the raw source bytes.
Here is a well-known idiom from distributed computing:
When the quote (without trailing whitespace) is encoded into Base64, it is represented as a byte sequence of 8-bit-padded ASCII characters encoded in MIME's Base64 scheme as follows (newlines and white spaces may be present anywhere but are to be ignored on decoding):
In the above quote, the encoded value of Man is TWFu. Encoded in ASCII, the characters M, a, and n are stored as the byte values 77, 97, and 110, which are the 8-bit binary values 01001101, 01100001, and 01101110. These three values are joined together into a |
https://en.wikipedia.org/wiki/MTV2 | MTV2 (formerly M2) is an American pay television channel owned by the Paramount Media Networks division of Paramount Global.
The channel launched initially as an all-music video service, once the original MTV had started to shift its programming. As with its parent network, MTV2's focus on music programming would gradually be downplayed during the 2000s. By 2011, MTV2 would primarily target young adult men with original and acquired lifestyle and reality programming, reruns of male-targeting shows from MTV, acquired sitcoms and movies, and a daily block of hip hop and rock genre videos in the early mornings. Due to Viacom's 2017 restructuring plan, MTV2's original programs were eventually moved over to the flagship MTV network, while the former network would drop its music video blocks in November of that year.
In February 2015, approximately 79,416,000 American households (68.2% of households with television) received MTV2.
History
1996–1999: Early history as M2
MTV2 began broadcasting as simply M2 on August 1, 1996 – MTV's 15th anniversary – with Beck's "Where It's At" being the first video to air. In its first few years on the air, M2 was restricted to satellite television plus the few, small markets where digital cable was then available, limiting its audience reach to around 12 million homes by 2000. M2 also broadcast live over the internet during its early years, which meant it was similarly ahead of its time in a period when few people had broadband internet connections.
M2's early years was known for its playful or ironic programming decisions that underscored the channel's free-wheeling, subversive attitude; on January 1, 1999, M2 played the music video "1999" by Prince for 24 hours straight. M2 quickly gained favor with music insiders, and as its popularity and reputation grew within the music industry, it became common for musicians and record labels to request that their new videos premiere exclusively on M2 rather than MTV. Record companies often asked to have new artists appear on the channel in taped segments with the VJs. The Spice Girls made their first U.S. television appearance on M2, as did their video for "Wannabe". At the time of their appearance on M2, the girl group was a huge success in the United Kingdom, but they were relatively unknown to U.S. audiences.
Starting on January 1, 2000, in honor of the millennium, MTV2 attempted to play every music video in the MTV library in alphabetical order. While a majority of videos were played, many were skipped over. The special ended in mid-April 2000.
1999–2005: Relaunch as MTV2
Due in part to the unexpectedly slow roll-out of the fledgling channel, MTV Networks decided to rebrand M2 in the first quarter of 1999, changing the name to MTV2. In 1997, MTV's owner Viacom had bought out the rival music channel The Box. Starting on January 1, 2001, all households that had received The Box began to receive MTV2 in its place, putting the channel into millions of additional house |
https://en.wikipedia.org/wiki/Wardialing | Wardialing (or war dialing) is a technique to automatically scan a list of telephone numbers, usually dialing every number in a local area code to search for modems, computers, bulletin board systems (computer servers) and fax machines. Hackers use the resulting lists for various purposes: hobbyists for exploration, and crackers—malicious hackers who specialize in breaching computer security—for guessing user accounts (by capturing voicemail greetings), or locating modems that might provide an entry-point into computer or other electronic systems. It may also be used by security personnel, for example, to detect unauthorized devices, such as modems or faxes, on a company's telephone network.
Process
A single wardialing call would involve calling an unknown number, and waiting for one or two rings, since answering computers usually pick up on the first ring. If the phone rings twice, the modem hangs up and tries the next number. If a modem or fax machine answers, the wardialer program makes a note of the number. If a human or answering machine answers, the wardialer program hangs up. Depending on the time of day, wardialing 10,000 numbers in a given area code might annoy dozens or hundreds of people, some who attempt and fail to answer a phone in two rings, and some who succeed, only to hear the wardialing modem's carrier tone and hang up. The repeated incoming calls are especially annoying to businesses that have many consecutively numbered lines in the exchange, such as used with a Centrex telephone system.
Some newer wardialing software, such as WarVOX, does not require a modem to conduct wardialing. Rather, such programs can use VOIP connections, which can speed up the number of calls that a wardialer can make. Sandstorm Enterprises has a patent on a multi-line war dialer. ("System and Method for Scan-Dialing Telephone Numbers and Classifying Equipment Connected to Telephone Lines Associated therewith.") The patented technology is implemented in Sandstorm's PhoneSweep war dialer.
Etymology
The popular name for this technique originated in the 1983 film WarGames. In the film, the protagonist programmed his computer to dial every telephone number in Sunnyvale, California to find other computer systems. Prior to the movie's release, this technique was known as "hammer dialing" or "demon dialing", but the film introduced the method to many, such as the members of The 414s. By 1985 at least one company advertised a "War Games Autodialer" for Commodore computers. Such programs became common on bulletin board systems of the time, with file names often truncated to wardial.exe and the like due to length restrictions of 8 characters on such systems. Eventually, the etymology of the name fell behind as "war dialing" gained its own currency within computing culture.
The popularity of wardialing in 1980s and 1990s prompted some states to enact legislation prohibiting the use of a device to dial telephone numbers without the intent of communicating w |
https://en.wikipedia.org/wiki/2000s%20in%20film | The decade of the 2000s in film involved many significant developments in the film industries around the world, especially in the technology used. Building on advancements from the 1990s, computers were used to create effects that would have previously been more expensive, from the subtle erasing of surrounding islands in Cast Away to the vast battle scenes such as those in The Matrix sequels and 300.
Trends
The 2000s saw the resurgence of several genres. Fantasy film franchises dominated the box office with The Lord of the Rings, Harry Potter, Pirates of the Caribbean, the Star Wars prequel trilogy (beginning in 1999), The Chronicles of Narnia, etc. Comic book superhero films became a blockbuster genre following the releases of X-Men, Unbreakable and Spider-Man; culminating in the unprecedented achievements of The Dark Knight both in terms of revenue and acclaim. Gladiator similarly sparked the revival of historical epic films. In contrast, the Bollywood-inspired Moulin Rouge! did the same for live action musical films in the Western world, where Indian musicals such as Lagaan and Devdas also began gaining mainstream exposure. Hong Kong fight choreographers like Yuen Woo-ping continued their influence in Hollywood with such martial arts films as Kill Bill: Volume 1 and Kill Bill: Volume 2, even leading to the spread of wire fu techniques into other subgenres, alongside filmmaker John Woo's gun fu from the likes of Mission: Impossible 2. The battle royale genre also began with the release of the Japanese film Battle Royale.
Film categories that were generally not popular in North America became increasingly attractive to western moviegoers. Non-English language films such as Crouching Tiger, Hidden Dragon, Hero, The Passion of the Christ and Pan's Labyrinth; as well as documentary films like An Inconvenient Truth, March of the Penguins, Super Size Me and Fahrenheit 9/11; ended up being very successful.
Computer animation replaced traditional animation as the dominant medium for animated feature films in American cinema (especially after the release of Shrek): DreamWorks Animation was the top animation studio in that decade, with Pixar and 20th Century Fox Animation following close behind (the latter after Fox Animation Studios was closed down on October 31, 2000). Further extending to the exploration of motion capture technology in such films as Robert Zemeckis' The Polar Express, Beowulf and A Christmas Carol. However, hand-drawn anime films also gained more exposure outside of Japan with the releases of Hayao Miyazaki's Spirited Away, Howl's Moving Castle and Ponyo; while stop-motion films regained popularity thanks to Chicken Run, Corpse Bride, Wallace & Gromit: The Curse of the Were-Rabbit and Coraline.
Major film studios started to focus their budgets on established titles with built-in fandoms to lower the risk of commercial failures and maximize financial profit. Increasing the productions of sequels, prequels, remakes, reboots, adap |
https://en.wikipedia.org/wiki/Michael%20A.%20Jackson%20%28computer%20scientist%29 | Michael Anthony Jackson (born 16 February 1936) is a British computer scientist, and independent computing consultant in London, England. He is also a visiting research professor at the Open University in the UK.
Biography
Born in Birmingham to Montagu M. Jackson and Bertha (Green) Jackson, Jackson was educated at Harrow School in Harrow, London, England. There he was taught by Christopher Strachey and wrote his first program under Strachey's guidance. From 1954 to 1958, he studied classics (known as "Greats") at Merton College, Oxford; a fellow student, two years ahead of him, was C. A. R. Hoare. They shared an interest in logic, which was studied as part of Greats at Oxford.
After his graduation in 1961, Jackson started as computer science designer and consultant for Maxwell Stamp Associates in London. Here he designed, coded and tested his first programs for IBM and Honeywell computers, working in assembler. There Jackson found his calling, as he recollected in 2000: "Although I was a careful designer — drawing meticulous flowcharts before coding — and a conscientious tester, I realised that program design was hard and the results likely to be erroneous..." Information system design was in need of a structured approach.
In 1964, Jackson joined the new consultancy firm John Hoskyns and Company in London, before founding his own company Michael Jackson Systems Limited in 1971. In the 1960s, he had started his search for a "more reliable and systematic way of programming." He contributed to the emerging modular programming movement, meeting Larry Constantine, George H. Mealy and several others on a 1968 symposium. In the 1970s, Jackson developed Jackson Structured Programming (JSP). In the 1980s, with John Cameron, he developed Jackson System Development (JSD). Then, in the 1990s, he developed the Problem Frames Approach.
As a part-time researcher at AT&T Labs Research, in collaboration with Pamela Zave, Jackson created "Distributed Feature Composition", a virtual architecture for specification and implementation of telecommunication services.
Jackson received the Stevens Award for Software Development Methods in 1997. and British Computer Society Lovelace Medal in 1998.
In 1961, Jackson married Judith Wendy Blackburn; they have four sons, one of whom, Daniel, is also a computer scientist based at MIT.
Work
Jackson has developed a series of methods. Each of these methods covers a wider scope than the previous one, and builds on ideas that appeared, but were not fully developed, in the previous one. Reading his books in sequence allows you to follow the evolution of his thinking.
Jackson Structured Programming
Jackson Structured Programming (JSP) was the first software development method that Jackson developed. It is a program design method, and was described in his book Principles of Program Design. JSP covers the design of individual programs, but not systems.
Jackson System Development
The Jackson System Development (JSD) was the sec |
https://en.wikipedia.org/wiki/Command%20%28computing%29 | In computing, a command is a directive to a computer program to perform a specific task. It may be issued via a command-line interface or as input to a network service as part of a network protocol, or as an event triggered in a graphical user interface.
Specifically, the term command is used in imperative programming languages. The name arises because statements in these languages are usually written in a manner similar to the imperative mood used in many natural languages. A statement in an imperative programming language would then be a sentence in a natural language, and the command would be the predicate.
Many programs allow specifically formatted arguments, known as flags or options, which modify the default behaviour of the program, while further arguments may provide objects, such as files, to act on. As an analogy to a natural language, the flags are adverbs, while the other arguments are objects.
Distinction between command and expression, statement and function
The meaning of command is highly dependent on context. For example, some authors refer to conditionals as commands while they are called expressions in Python or Bash and statements in JAVA.
Similarly, writing to stdout is done in Bash with the builtin command printf, while it is done with the built-in function print() in Python.
Examples
Here are some commands given to a command-line interpreter (Unix shell).
The following command changes the user's working position in the directory tree to the directory /home/pete. The utility program is cd and the argument is /home/pete:
cd /home/pete
The following command prints the text Hello World on the standard output stream, which, in this case, just prints the text on the screen. The program name is echo and the argument is "Hello World". The quotes are used to prevent Hello and World being treated as separate tokens:
echo "Hello World"
The following commands are equivalent. They list files in the directory /bin. The program is ls, having three flags (l, t, r), and the argument is the directory /bin:
ls -l -t -r /bin
ls -ltr /bin
The following command displays the contents of the files ch1.txt and ch2.txt. The program name is cat, having two file name arguments:
cat ch1.txt ch2.txt
Here are some commands for the DOS, OS/2 and Microsoft Windows command prompt processor. The following command displays the contents of the file readme.txt. The program name is type and the argument is readme.txt.
type readme.txt
The following command lists the contents of the current directory. The program name is dir, and Q is a flag requesting that the owner of each file also be listed.
dir /Q
See also
Gesture recognition
List of Unix commands
List of DOS commands
Formal grammar
References
External links
command from FOLDOC
Windows Commands | Microsoft Docs
User interfaces
Computing terminology |
https://en.wikipedia.org/wiki/RCP | RCP may refer to:
Architecture
Reinforced concrete pipe
Reflected ceiling plan
Computer technology
RCP (chip), a co-processor chip designed by Silicon Graphics for use in the Nintendo 64 gaming system
rcp (Unix), a command on the Unix operating systems that is used to remote copy a file
Rapid control prototyping, a process that lets engineers quickly test and iterate their control strategies
Restore Cursor Position (ANSI), an ANSI X3.64 escape sequence
Rich Client Platform, a software development platform helping software developers to rapidly build new applications
Remote Control Protocol, a protocol that allows CEC enabled TVs to control MHL compatible devices
Medicine
Respiratory Care Practitioner
Retrograde cholangiopancreatography
Royal College of Physicians, located in London, Edinburgh, and Ireland
Organizations
Radio Club Paraguayo, an amateur radio organization in Paraguay
Radio Club Peruano, an amateur radio organization in Peru
Radio Corporation of the Philippines, the oldest radio network in the Philippines
Rochester Community Players, a theatrical company in Rochester, NY
Businesses
RCP Design Global, a French design agency
RIT Capital Partners, a large UK investment trust
Political groups
Revolutionary Communist Party (disambiguation), the name of several revolutionary communist parties worldwide
Romanian Communist Party
Russian Communist Party, the second of four names used at different times by the Communist Party of the Soviet Union
Science
Reactor Coolant Pumps in International Reactor Innovative and Secure nuclear reactors
Representative Concentration Pathways, scenarios of greenhouse gas trajectories
Right circular polarization, in radio communications/radio astronomy
Rapid crack propagation, in testing of plastic pipes
Radiochemical purity, % radiodetected peak area of the intact radiolabeled peptide vs all radio peaks measured during the same analyses
Other uses
Radio College Park, a Persian podcast
Random close pack, packing method for objects
RealClearPolitics, a political website
Retention Control Point, high year tenure in the United States Army
Rose City Park, Portland, Oregon, United States
Royal Commonwealth Pool in Edinburgh, Scotland, UK |
https://en.wikipedia.org/wiki/VH1 | VH1 (originally an initialism of Video Hits One) is an American basic cable television network based in New York City. It was created by Warner-Amex Satellite Entertainment, at the time a division of Warner Communications and the original owner of MTV, and launched on January 1, 1985, in the former space of Turner Broadcasting System's short-lived Cable Music Channel. The channel is currently owned by Paramount Global (formerly Viacom and ViacomCBS).
The channel was originally conceived to build upon the success of then-sister channel MTV by playing music videos targeting a slightly older demographic than MTV by focusing on the lighter, softer side of popular music. Like MTV, VH1 ultimately drifted away from music videos and into reality television programming, albeit with a focus on music personalities and celebrities, and shows targeting African American audiences. VH1 is best known for franchises such as Behind the Music, the I Love… series, the Celebreality block, Love & Hip Hop, and RuPaul's Drag Race.
As of July 2023, approximately 90.2 million US households received VH1.
History
Early history (1985–1994)
Format and VJs (1985–89)
VH1's aim was to focus on the lighter, softer side of popular music, including US and international musicians such as Olivia Newton-John, Kenny Rogers, Carly Simon, Tina Turner, Elton John, Billy Joel, Eric Clapton, Sting, Donna Summer, Rod Stewart, Kenny G, Michael Bolton, Anita Baker, Chicago, and Fleetwood Mac, in hopes of appealing to people aged 18 to 35, and possibly older. Also frequently featured in the network's early years were "videos" for Motown and other '60s oldies consisting of newsreel and concert footage. It was introduced on January 1, 1985, with the video performance of "The Star-Spangled Banner" by Marvin Gaye, who died a year before the network launched (the national anthem was also played at the launch of Cable Music Channel).
From the start, Video Hits One was branded as an urban version of its sister/parent channel. It played more jazz and R&B artists than MTV and had a higher rotation of urban-contemporary performers. Its early on-camera personalities were New York radio veterans Don Imus (then of WNBC), Frankie Crocker (then program director and DJ for WBLS), Scott Shannon (of WHTZ), Jon Bauman ("Bowzer" from Sha Na Na), and Rita Coolidge.
Later VJs included Bobby Rivers, who joined in 1987, Tim Byrd of WPIX-FM (the current day FM rebroadcast of WFAN), a station whose eclectic ballad-and-R&B oriented format mirrored that of VH-1, Roger Rose - Actor and comedian (Ski Patrol), and Alison Steele ("The Nightbird" of WNEW-FM). Rosie O'Donnell later joined the outlet's VJ lineup. O'Donnell would also host a comedy show featuring various comedians each episode. As an added touch to make the network more like a televised radio station, the early years of the network featured jingles in their bumpers produced by JAM Creative Productions in Dallas, who had previously made jingles for radio |
https://en.wikipedia.org/wiki/Gambas | Gambas is the name of an object-oriented dialect of the BASIC programming language, as well as the integrated development environment that accompanies it. Designed to run on Linux and other Unix-like computer operating systems, its name is a recursive acronym for Gambas Almost Means Basic. Gambas is also the word for prawns in the Spanish, French, and Portuguese languages, from which the project's logos are derived.
History
Gambas was developed by the French programmer Benoît Minisini, with its first release coming in 1999. Benoît had grown up with the BASIC language, and decided to make a free software development environment that could quickly and easily make programs with user interfaces.
The Gambas 1.x versions featured an interface made up of several different separate windows for forms and IDE dialogues in a similar fashion to the interface of earlier versions of the GIMP. It could also only develop applications using Qt and was more oriented towards the development of applications for KDE. The last release of the 1.x versions was Gambas 1.0.19.
The first of the 2.x versions was released on January 2, 2008, after three to four years of development. It featured a major redesign of the interface, now with all forms and functions embedded in a single window, as well as some changes to the Gambas syntax, although for the most part code compatibility was kept. It featured major updates to existing Gambas components as well as the addition of some new ones, such as new components that could use GTK+ or SDL for drawing or utilize OpenGL acceleration. Gambas 2.x versions can load up and run Gambas 1.x projects, with occasional incompatibilities; the same is true for Gambas 2.x to 3.x, but not from Gambas 1.x to 3.x.
The next major iteration of Gambas, the 3.x versions, was released on December 31, 2011. A 2015 benchmark published on the Gambas website showed Gambas 3.8.90 scripting as being faster to varying degrees than Perl 5.20.2 and the then-latest 2.7.10 version of Python in many tests. Version 3.16.0 released on April 20, 2021, featured full support for Wayland using the graphical components, as well as parity between the Qt 5 and GTK 3 components.
Features
Gambas is designed to build graphical programs using the Qt (currently Qt 4.x or 5.x since 3.8.0) or the GTK toolkit (GTK 3.x also supported as of 3.6.0); the Gambas IDE is written in Gambas. Gambas includes a GUI designer to aid in creating user interfaces in an event-driven style, but can also make command line applications, as well as text-based user interfaces using the ncurses toolkit. The Gambas runtime environment is needed to run executables.
Functionality is provided by a variety of components, each of which can be selected to provide additional features. Drawing can be provided either through Qt and GTK toolkits, with an additional component which is designed to switch between them. Drawing can also be provided through the Simple DirectMedia Layer (originally version |
https://en.wikipedia.org/wiki/Win32s | Win32s is a 32-bit application runtime environment for the Microsoft Windows 3.1 and 3.11 operating systems. It allowed some 32-bit applications to run on the 16-bit operating system using call thunks. A beta version of Win32s was available in October 1992. Version 1.10 was released in July 1993 simultaneously with Windows NT 3.1.
Concept and characteristics
Win32s was intended as a partial implementation of the Win32 Windows API as it existed in early versions of Windows NT.
The "s" in Win32s signifies subset, as Win32s lacked a number of Windows NT functions, including multi-threading, asynchronous I/O, newer serial port functions and many GDI extensions. This generally limited it to "Win32s applications" which were specifically designed for the Win32s platform, although some standard Win32 programs would work correctly, including Microsoft's 3D Pinball Space Cadet and some of Windows 95's included applets. Early versions of Internet Explorer (up to Version 5) were also Win32s compatible, although these also existed in 16-bit format. Generally, for a 32-bit application to be compatible with Win32s, it had to not use more than 16MB of memory or any extended features such as DirectX.
Win32s inherits many of the limitations of the Win16 environment. True Win32 applications execute within a private virtual address space, whereas Windows 3.x used an address space shared among all running applications. An application running on Win32s has the shared address space and cooperative multitasking characteristics of Windows 3.1. Consequently, for a Win32 application to run on Win32s, it must contain relocation information.
A technique named thunking is fundamental to the implementation of Win32s as well as Chicago-kernel operating systems, which are Windows 95, Windows 98, and Windows ME. However, allowing user-level thunking greatly complicates attempts to provide stable memory management or memory protection on a system-wide basis, as well as core or kernel security—this allows poorly written applications to undermine system stability on Win32s, as well as the Chicago-kernel systems. 32-bit versions of Windows NT transparently provide a virtual machine for running Win16 applications, although this feature was removed from 64-bit versions of Windows.
Compatibility
Win32s-compatible applications could be built using Microsoft's development tools, as well as at least Borland C++ 4.x and Symantec C++ (now Digital Mars C++). However, several program compilation options (such as EXE relocation information) and DLLs which were implicit in Windows NT 3.1 have to be included with the application in Win32s. Microsoft ceased support for Win32s in Visual C++ version 4.2 released in late 1996.
Win32s included an implementation of the card game FreeCell as an example application, a couple of years before the game became famous with its inclusion in Windows 95.
Warcraft II: Tides of Darkness, a DOS game, included a level editor that required Win32s to run. T |
https://en.wikipedia.org/wiki/At%20%28command%29 | In computing, at is a command in Unix-like operating systems, Microsoft
Windows, and ReactOS used to schedule commands to be executed once, at a particular time in the future.
Design
Unix-like
On Unix-like operating systems, at reads a series of commands from standard input and collects them into one "at-job" which is carried out at a later date. The job inherits the current environment, so that it is executed in the same working directory and with the same environment variables set as when it was scheduled.
It differs from cron, which is used for recurring executions (e.g. once an hour, every Tuesday, January 1 every year). As with cron, many Unix systems allow the administrator to restrict access to the at command.
at can be made to mail a user when done carrying out a scheduled job, can use more than one job queue, and can read a list of jobs to carry out from a file instead of standard input.
The Linux at command was mostly written by Thomas Koenig.
Microsoft Windows and ReactOS
In addition to the graphical user interface for Windows Task Scheduler in Control Panel, Windows provides an at.exe command that schedules commands and programs to run on a computer at a specified time and date (similar to cron). It is available since Windows NT, but is now deprecated in favor of schtasks. It can only be used when the Schedule service is running. When used without parameters, at.exe lists scheduled commands.
at.exe cannot access tasks created or modified by Control Panel or schtasks.exe. Also, tasks created with at.exe are not interactive by default; interactivity needs to be explicitly requested.
The ReactOS implementation is based on the Windows variant. It was developed by Eric Kohl and is licensed under the GPLv2.
Usage
Unix-like
A sample command to compile a C program at 11:45 a. m. on January 31 would be:
$ echo "cc -o foo foo.c" | at 1145 jan 31
or
$ at 1145 jan 31
at> cc -o foo foo.c
at> ^D #(press Control-D while at the beginning of a line)
The atq program lists the currently queued jobs, while atrm removes jobs from the queue:
$ atq
1234 2011-08-12 11:45 cc -o foo foo.c user
$ atrm 1234
$ atq
$
In some Unix-like computer operating systems, it uses a daemon, atd, which waits in the background periodically checking the list of jobs to do and executing those at their scheduled time on behalf of at.
Variants
The command can be used instead of at to only run scheduled jobs if the system's load average is below a certain value.
Microsoft Windows and ReactOS
To use at.exe, the user must be a member of the local Administrators group.
The command-syntax is:
at [\\ComputerName] [{[ID] [/delete]|/delete [/yes]}]
at [[\\ComputerName] hours:minutes [/interactive] [{/every:date[,...]|/next:date[,...]}] command]
\\ ComputerName – This parameter specifies a remote computer. If it is omitted, at schedules the commands and programs on the local computer.
ID – This parameter specifies the identification number assigned to a scheduled command |
https://en.wikipedia.org/wiki/Anita%20Borg | Anita Borg (January 17, 1949 – April 6, 2003) was an American computer scientist celebrated for advocating for women’s representation and professional advancement in technology. She founded the Institute for Women and Technology and the Grace Hopper Celebration of Women in Computing.
Education and early life
Borg was born Anita Borg Naffz in Chicago, Illinois. She grew up in Palatine, Illinois; Kaneohe, Hawaii; and Mukilteo, Washington. Borg got her first programming job in 1969. Although she loved math while growing up, she did not originally intend to go into computer science and taught herself how to program while working at a small insurance company. She was awarded a PhD in Computer Science by New York University in 1981 for research investigating the synchronization efficiency of operating systems supervised by Robert Dewar and Gerald Belpaire.
She died from brain cancer, in Sonoma, California on 6 April 2003.
Career
After receiving her PhD, Borg spent four years building a fault tolerant Unix-based operating system, first for Auragen Systems Corp. of New Jersey and then with Nixdorf Computer in Germany.
In 1986, she began working for Digital Equipment Corporation, where she spent 12 years, first at the Western Research Laboratory. While at Digital Equipment, she developed and patented a method for generating complete address traces for analyzing and designing high-speed memory systems. Her experience running the ever-expanding Systers mailing list, which she founded in 1987, led her to work in email communication. As a consultant engineer in the Network Systems Laboratory under Brian Reid, she developed MECCA, an email and Web-based system for communicating in virtual communities.
In 1997, Borg left Digital Equipment Corporation and began working as a researcher in the Office of the Chief Technology Officer at Xerox PARC. Soon after starting at Xerox, she founded the Institute for Women and Technology, having previously founded the Grace Hopper Celebration of Women in Computing in 1994.
Advocacy for technical women
Borg passionately believed in working for greater representation of women in technology. Her goal was to have 50% representation for women in computing by 2020. She strove for technical fields to be places where women would be equally represented at all levels of the pipeline, and where women could impact, and benefit from, technology.
Systers
In 1987, Borg founded Systers, the first email network for women in technology. While attending the Symposium on Operating Systems Principles (SOSP), she was struck by how few women were present at the conference. She and six or seven other women met in the ladies' room and talked about how few women there were in computing. A dozen of the women at the conference made plans to eat lunch together, and that is where the idea for Systers was formed.
Systers was established to provide a private space for its members to seek input and share advice based on their common experiences. Sys |
https://en.wikipedia.org/wiki/Newton%20polynomial | In the mathematical field of numerical analysis, a Newton polynomial, named after its inventor Isaac Newton, is an interpolation polynomial for a given set of data points. The Newton polynomial is sometimes called Newton's divided differences interpolation polynomial because the coefficients of the polynomial are calculated using Newton's divided differences method.
Definition
Given a set of k + 1 data points
where no two xj are the same, the Newton interpolation polynomial is a linear combination of Newton basis polynomials
with the Newton basis polynomials defined as
for j > 0 and .
The coefficients are defined as
where
is the notation for divided differences.
Thus the Newton polynomial can be written as
Newton forward divided difference formula
The Newton polynomial can be expressed in a simplified form when
are arranged consecutively with equal spacing.
Introducing the notation
for each
and ,
the difference can be written as .
So the Newton polynomial becomes
This is called the Newton forward divided difference formula.
Newton backward divided difference formula
If the nodes are reordered as , the Newton polynomial becomes
If are equally spaced with and for i = 0, 1, ..., k, then,
is called the Newton backward divided difference formula.
Significance
Newton's formula is of interest because it is the straightforward and natural differences-version of Taylor's polynomial. Taylor's polynomial tells where a function will go, based on its y value, and its derivatives (its rate of change, and the rate of change of its rate of change, etc.) at one particular x value. Newton's formula is Taylor's polynomial based on finite differences instead of instantaneous rates of change.
Addition of new points
As with other difference formulas, the degree of a Newton interpolating polynomial can be increased by adding more terms and points without discarding existing ones. Newton's form has the simplicity that the new points are always added at one end: Newton's forward formula can add new points to the right, and Newton's backward formula can add new points to the left.
The accuracy of polynomial interpolation depends on how close the interpolated point is to the middle of the x values of the set of points used. Obviously, as new points are added at one end, that middle becomes farther and farther from the first data point. Therefore, if it isn't known how many points will be needed for the desired accuracy, the middle of the x-values might be far from where the interpolation is done.
Gauss, Stirling, and Bessel all developed formulae to remedy that problem.
Gauss's formula alternately adds new points at the left and right ends, thereby keeping the set of points centered near the same place (near the evaluated point). When so doing, it uses terms from Newton's formula, with data points and x values renamed in keeping with one's choice of what data point is designated as the x0 data point.
Stirling's formula remains centered abou |
https://en.wikipedia.org/wiki/Elasticity | Elasticity often refers to:
Elasticity (physics), continuum mechanics of bodies that deform reversibly under stress
Elasticity may also refer to:
Information technology
Elasticity (data store), the flexibility of the data model and the clustering
Elasticity (system resource), a defining feature of distributed system
Economics
Elasticity (economics), a general term for a ratio of change. For more specific economic forms of elasticity, see:
Beta (finance)
Cross elasticity of demand
Elasticity of substitution
Frisch elasticity of labor supply
Income elasticity of demand
Output elasticity
Price elasticity of demand
Price elasticity of supply
Yield elasticity of bond value
Mathematics
Elasticity of a function, a mathematical definition of point elasticity
Arc elasticity
Other uses
Elasticity, a 2021 EP by Serj Tankian
Elasticity coefficient, a biochemical term used in metabolic control analysis
See also
Elastic (disambiguation) |
https://en.wikipedia.org/wiki/Boot%20sector | A boot sector is the sector of a persistent data storage device (e.g., hard disk, floppy disk, optical disc, etc.) which contains machine code to be loaded into random-access memory (RAM) and then executed by a computer system's built-in firmware (e.g., the BIOS).
Usually, the very first sector of the hard disk is the boot sector, regardless of sector size (512 or 4096 bytes) and partitioning flavor (MBR or GPT).
The purpose of defining one particular sector as the boot sector is inter-operability between firmware and various operating systems.
The purpose of chain loading first a firmware (e.g., the BIOS), then some code contained in the boot sector, and then, for example, an operating system, is maximal flexibility.
The IBM PC and compatible computers
On an IBM PC compatible machine, the BIOS selects a boot device, then copies the first sector from the device (which may be an MBR, VBR or any executable code), into physical memory at memory address 0x7C00. On other systems, the process may be quite different.
Unified Extensible Firmware Interface (UEFI)
The UEFI (not legacy boot via CSM) does not rely on boot sectors, UEFI system loads the boot loader (EFI application file in USB disk or in the EFI system partition) directly. Additionally, the UEFI specification also contains "secure boot", which basically wants the UEFI code to be digitally signed.
Damage to the boot sector
In case a boot sector receives physical damage, the hard disk will no longer be bootable, unless used with a custom BIOS that defines a non-damaged sector as the boot sector. However, since the very first sector additionally contains data regarding the partitioning of the hard disk, the hard disk will become entirely unusable except when used in conjunction with custom software.
Partition tables
A disk can be partitioned into multiple partitions and, on conventional systems, it is expected to be. There are two definitions on how to store the information regarding the partitioning:
A master boot record (MBR) is the first sector of a data storage device that has been partitioned. The MBR sector may contain code to locate the active partition and invoke its volume boot record.
A volume boot record (VBR) is the first sector of a data storage device that has not been partitioned, or the first sector of an individual partition on a data storage device that has been partitioned. It may contain code to load an operating system (or other standalone program) installed on that device or within that partition.
The presence of an IBM PC compatible boot loader for x86-CPUs in the boot sector is by convention indicated by a two-byte hexadecimal sequence 0x55 0xAA (called the boot sector signature) at the end of the boot sector (offsets 0x1FE and 0x1FF). This signature indicates the presence of at least a dummy boot loader which is safe to be executed, even if it may not be able actually to load an operating system. It does not indicate a particular (or even the presence |
https://en.wikipedia.org/wiki/Daisyworld | Daisyworld, a computer simulation, is a hypothetical world orbiting a star whose radiant energy is slowly increasing or decreasing. It is meant to mimic important elements of the Earth-Sun system. James Lovelock and Andrew Watson introduced it in a paper published in 1983 to illustrate the plausibility of the Gaia hypothesis. In the original 1983 version, Daisyworld is seeded with two varieties of daisy as its only life forms: black daisies and white daisies. White petaled daisies reflect light, while black petaled daisies absorb light. The simulation tracks the two daisy populations and the surface temperature of Daisyworld as the sun's rays grow more powerful. The surface temperature of Daisyworld remains almost constant over a broad range of solar output.
Mathematical model to sustain the Gaia hypothesis
The purpose of the model is to demonstrate that feedback mechanisms can evolve from the actions or activities of self-interested organisms, rather than through classic group selection mechanisms. Daisyworld examines the energy budget of a planet populated by two different types of plants, black daisies and white daisies. The colour of the daisies influences the albedo of the planet such that black daisies absorb light and warm the planet, while white daisies reflect light and cool the planet. Competition between the daisies (based on temperature-effects on growth rates) leads to a balance of populations that tends to favour a planetary temperature close to the optimum for daisy growth.
Lovelock and Watson demonstrated the stability of Daisyworld by making its sun evolve along the main sequence, taking it from low to high solar constant. This perturbation of Daisyworld's receipt of solar radiation caused the balance of daisies to gradually shift from black to white but the planetary temperature was always regulated back to this optimum (except at the extreme ends of solar evolution). This situation is very different from the corresponding abiotic world, where temperature is unregulated and rises linearly with solar output.
Later versions of Daisyworld introduced a range of grey daisies, as well as populations of grazers and predators, and found that these further increased the stability of the homeostasis. More recently, other research, modeling the real biochemical cycles of Earth, and using various types of organisms (e.g. photosynthesisers, decomposers, herbivores and primary and secondary carnivores) has also been shown to produce Daisyworld-like regulation and stability, which helps to explain planetary biological diversity.
This enables nutrient recycling within a regulatory framework derived by natural selection amongst species, where one being's harmful waste becomes low energy food for members of another guild. This research on the Redfield ratio of nitrogen to phosphorus shows that local biotic processes can regulate global systems (See Keith Downing & Peter Zvirinsky, The Simulated Evolution of Biochemical Guilds: Reconcil |
https://en.wikipedia.org/wiki/John%20Draper | John Thomas Draper (born March 11, 1943), also known as Captain Crunch, Crunch, or Crunchman (after the Cap'n Crunch breakfast cereal mascot), is an American computer programmer and former phone phreak. He is a widely known figure within the computer programming world and the hacker and security community, and generally lives a nomadic lifestyle.
In 2017, the organizers of several computer security events banned him from attending following published allegations of sexually inappropriate behavior. Draper denied some of the allegations, but did not directly address others.
Early life
Draper is the son of a United States Air Force engineer. As a child, he built a home radio station from discarded military components. He was frequently bullied in school and briefly received psychological treatment.
After taking college courses, Draper enlisted in the U.S. Air Force in 1964. While stationed in Alaska, he helped his fellow service members make free phone calls home by devising access to a local telephone switchboard. In 1967, while stationed at Charleston Air Force Station in Maine, he created WKOS (W-"chaos"), a pirate radio station in nearby Dover-Foxcroft, but shut it down after a legally-licensed radio station, WDME, objected.
Draper was honorably discharged from the Air Force as an Airman First Class in 1968. He moved to Silicon Valley and briefly worked for National Semiconductor as an engineering technician and at Hugle International where he worked on early designs for a cordless telephone. He also attended De Anza College on a part-time basis through 1972.
During this period, he also worked as an engineer and disc jockey for KKUP in Cupertino, California and adopted the countercultural styles of the time by wearing long hair and smoking marijuana.
Career
Phreaking
While testing a pirate radio transmitter he had built, Draper broadcast a telephone number to listeners seeking feedback to gauge the station's reception. A call from fellow pirate radio operator Denny Teresi resulted in a meeting that led Draper into the world of "phone phreaks", people who study and experiment with telephone networks, and who sometimes use that knowledge to make free calls. Teresi and several other phone phreaks were blind. Learning of Draper's knowledge of electronic design, they asked him to build a multifrequency tone generator, known informally as a blue box, a device for emitting audio tones used to control the phone network. The group had previously used an organ and cassette recordings of tones to make free calls. Among the phone phreaks, one blind boy who had taken the moniker of Joybubbles had perfect pitch and was able to identify frequencies precisely.
Draper learned that a toy whistle packaged in boxes of Cap'n Crunch cereal emitted a tone at precisely 2600 hertz—the same frequency that AT&T long lines used to indicate that a trunk line was available for routing a new call. The tone disconnected one end of the trunk while the still-connected |
https://en.wikipedia.org/wiki/Wardriving | Wardriving is the act of searching for Wi-Fi wireless networks, usually from a moving vehicle, using a laptop or smartphone. Software for wardriving is freely available on the internet.
Warbiking, warcycling, warwalking and similar use the same approach but with other modes of transportation.
Etymology
War driving originated from wardialing, a method popularized by a character played by Matthew Broderick in the film WarGames, and named after that film. War dialing consists of dialing every phone number in a specific sequence in search of modems.
Variants
Warbiking or warcycling is similar to wardriving, but is done from a moving bicycle or motorcycle. This practice is sometimes facilitated by mounting a Wi-Fi enabled device on the vehicle.
Warwalking, or warjogging, is similar to wardriving, but is done on foot rather than from a moving vehicle. The disadvantages of this method are a slower speed of travel (leading to the discovery of more infrequently discovered networks) and the absence of a convenient computing environment. Consequently, handheld devices such as pocket computers, which can perform such tasks while users are walking or standing, have dominated this practice. Technology advances and developments in the early 2000s expanded the extent of this practice. Advances include computers with integrated Wi-Fi, rather than CompactFlash (CF) or PC Card (PCMCIA) add-in cards in computers such as Dell Axim, Compaq iPAQ and Toshiba pocket computers starting in 2002. Later, the active Nintendo DS and Sony PSP enthusiast communities gained Wi-Fi abilities on these devices. Further, nearly all modern smartphones integrate Wi-Fi and Global Positioning System (GPS).
Warrailing, or Wartraining, is similar to wardriving, but is done on a train or tram rather than from a slower more controllable vehicle. The disadvantages of this method are higher speed of travel (resulting in less discovery of more infrequently discovered networks) and often limited to major roads with higher traffic.
Warkitting is a combination of wardriving and rootkitting. In a warkitting attack, a hacker replaces the firmware of an attacked router. This allows them to control all traffic for the victim, and could even permit them to disable TLS by replacing HTML content as it is being downloaded. Warkitting was identified by Tsow, Jakobsson, Yang, and Wetzel.
Warflying is a variant utilizing aircraft flying around and locating nodes. It was first performed in Perth with a Grumman Tiger in August 2002, and a week later in San Diego in August 2002 in a Cessna 182.
Mapping
Wardrivers use a Wi-Fi-equipped device together with a GPS device to record the location of wireless networks. The results can then be uploaded to websites like WiGLE, or Geomena where the data is processed to form maps of the network neighborhood. There are also clients available for smartphones running Android that can upload data directly. For better range and sensitivity, antennas are built or boug |
https://en.wikipedia.org/wiki/Vampire%20tap | A vampire tap (also called a piercing tap) is a device for physically connecting a station, typically a computer, to a network that used 10BASE5 cabling. This device clamped onto and "bit" into the cable (hence the name "vampire"), inserting a probe through a hole drilled using a special tool through the outer shielding to contact the inner conductor, while other spikes bit into the outer conductor.
The vampire tap usually had an integrated AUI (Attachment Unit Interface), from which a short multicore cable connected to the network card in the station.
Vampire taps allowed new connections to be made on a given physical cable while the cable was in use. This allowed administrators to expand bus topology network sections without interrupting communications. Without a vampire tap, the cable had to be cut and connectors had to be attached to both ends.
See also
Network tap
Insulation-displacement connector
References
Ethernet cables
Networking hardware |
https://en.wikipedia.org/wiki/Network%20Information%20Service | The Network Information Service, or NIS (originally called Yellow Pages or YP), is a client–server directory service protocol for distributing system configuration data such as user and host names between computers on a computer network. Sun Microsystems developed the NIS; the technology is licensed to virtually all other Unix vendors.
Because British Telecom PLC owned the name "Yellow Pages" as a registered trademark in the United Kingdom for its paper-based, commercial telephone directory, Sun changed the name of its system to NIS, though all the commands and functions still start with "yp".
A NIS/YP system maintains and distributes a central directory of user and group information, hostnames, e-mail aliases and other text-based tables of information in a computer network. For example, in a common UNIX environment, the list of users for identification is placed in and secret authentication hashes in . NIS adds another "global" user list which is used for identifying users on any client of the NIS domain.
Administrators have the ability to configure NIS to serve password data to outside processes to authenticate users using various versions of the Unix crypt(3) hash algorithms. However, in such cases, any NIS(0307) client can retrieve the entire password database for offline inspection.
Successor technologies
The original NIS design was seen to have inherent limitations, especially in the areas of scalability and security, so other technologies have come to replace it.
Sun introduced NIS+ as part of Solaris 2 in 1992, with the intention for it to eventually supersede NIS. NIS+ features much stronger security and authentication features, as well as a hierarchical design intended to provide greater scalability and flexibility. However, it was also more cumbersome to set up and administer, and was more difficult to integrate into an existing NIS environment than many existing users wished. NIS+ has been removed from Solaris 11.
As a result, many users choose to stick with NIS, and over time other modern and secure distributed directory systems, most notably Lightweight Directory Access Protocol (LDAP), came to replace it. For example, slapd (the standalone LDAP daemon) generally runs as a non-root user, and SASL-based encryption of LDAP traffic is natively supported.
On large LANs, DNS servers may provide better nameserver functionality than NIS or LDAP can provide, leaving just site-wide identification information for NIS master and slave systems to serve. However, some functionssuch as the distribution of netmask information to clients, as well as the maintenance of e-mail aliasesmay still be performed by NIS or LDAP. NIS maintains an NFS database information file as well as so called maps.
See also
Dynamic Host Configuration Protocol (DHCP)
Hesiod (name service)
Name Service Switch (NSS)
Network information system, for a broader use of NIS to manage other system and networks
References
External links
RHEL 9 will |
https://en.wikipedia.org/wiki/Network%20information%20system | A network information system (NIS) is an information system for managing networks, such as electricity network, water supply network, gas supply network, telecommunications network., or street light network
NIS may manage all data relevant to the network, e.g.- all components and their attributes, the connectivity between them and other information, relating to the operation, design and construction of such networks.
NIS for electricity may manage any, some or all voltage levels- Extra High, High, Medium and low voltage. It may support only the distribution network or also the transmission network.
Telecom NIS typically consists of the physical network inventory and logical network inventory. Physical network inventory is used to manage outside plant components, such as cables, splices, ducts, trenches, nodes and inside plant components such as active and passive devices. The most differentiating factor of telecom NIS from traditional GIS is the capability of recording thread level connectivity. The logical network inventory is used to manage the logical connections and circuits utilizing the logical connections. Traditionally, the logical network inventory has been a separate product but in most modern systems the functionality is built in the GIS serving both the functionality of the physical network and logical network.
Water network information system typically manages the water network components, such as ducts, branches, valves, hydrants, reservoirs and pumping stations. Some systems such as include the water consumers as well as water meters and their readings in the NIS. Sewage and stormwater components are typically included in the NIS. By adding sensors as well as analysis and calculations based on the measured values the concept of Smart water system is included in the NIS. By adding actuators into the network the concept of SCADA can be included in the NIS.
NIS may be built on top of a GIS (Geographical information system).
Private Cloud based NIS is gaining in functionality and popularity. As much of the changes to the network are conducted on the field, this approach has significant benefits compared to traditional GIS. The as-builts can be documented on site using mobile connectivity to the NIS. Many of the products in this category, such as by Keypro offer easy to use web interface which requires no installations at the client workstation.
References
External links
Resources on how to replace NIS can be found at the NIS Migration Resource Site
Computer networking |
https://en.wikipedia.org/wiki/EDA | EDA or Eda may refer to:
Computing
Electronic design automation
Enterprise Desktop Alliance, a computer technology consortium
Enterprise digital assistant
Estimation of distribution algorithm
Event-driven architecture
Exploratory data analysis
Government and politics
Economic Development Administration, an agency of the United States government
Election Defense Alliance, an American voting integrity organization
European Defence Agency, a branch of the European Union
European Democratic Alliance, a former political group in the European Parliament
(Federal Department of Foreign Affairs), a branch of the government of Switzerland
(Spanish Air Force), the air force of Spain
(United Democratic Left) (1951-1967, 1977-1985), a former Greek political party
Electoral District Association, a local unit of a political party in Canada
People
Eda (given name), a given name
Eda (surname), a Japanese surname
Places
Eda, Sweden
Eda (building), a residential high-rise building in Salford Quays, England
Eda glasbruk, Sweden
Eda Station (disambiguation)
Science and medicine
Ectodysplasin A, a protein
Electrodermal activity
Electron donor acceptor complexes, a type of Charge-transfer complex
European Delirium Association
Exploratory data analysis
Extreme demand avoidance, a behavioral profile associated with severe anxiety and autism
Other uses
EDA Awards, American film awards
Eda IF, a Swedish sport club
Eighth Doctor Adventures, a series of novels based on the television series Doctor Who
"Eating, Drinking, Adventure". A good mixture of social elements for a decent first Tinder date. |
https://en.wikipedia.org/wiki/Electronic%20design%20automation | Electronic design automation (EDA), also referred to as electronic computer-aided design (ECAD), is a category of software tools for designing electronic systems such as integrated circuits and printed circuit boards. The tools work together in a design flow that chip designers use to design and analyze entire semiconductor chips. Since a modern semiconductor chip can have billions of components, EDA tools are essential for their design; this article in particular describes EDA specifically with respect to integrated circuits (ICs).
History
Early days
The earliest electronic design automation is attributed to IBM with the documentation of its 700 series computers in the 1950s.
Prior to the development of EDA, integrated circuits were designed by hand and manually laid out. Some advanced shops used geometric software to generate tapes for a Gerber photoplotter, responsible for generating a monochromatic exposure image, but even those copied digital recordings of mechanically drawn components. The process was fundamentally graphic, with the translation from electronics to graphics done manually; the best-known company from this era was Calma, whose GDSII format is still in use today. By the mid-1970s, developers started to automate circuit design in addition to drafting and the first placement and routing tools were developed; as this occurred, the proceedings of the Design Automation Conference catalogued the large majority of the developments of the time.
The next era began following the publication of "Introduction to VLSI Systems" by Carver Mead and Lynn Conway in 1980; considered the standard textbook for chip design. The result was an increase in the complexity of the chips that could be designed, with improved access to design verification tools that used logic simulation. The chips were easier to lay out and more likely to function correctly, since their designs could be simulated more thoroughly prior to construction. Although the languages and tools have evolved, this general approach of specifying the desired behavior in a textual programming language and letting the tools derive the detailed physical design remains the basis of digital IC design today.
The earliest EDA tools were produced academically. One of the most famous was the "Berkeley VLSI Tools Tarball", a set of UNIX utilities used to design early VLSI systems. Still widely used are the Espresso heuristic logic minimizer, responsible for circuit complexity reductions and Magic, a computer-aided design platform. Another crucial development was the formation of MOSIS, a consortium of universities and fabricators that developed an inexpensive way to train student chip designers by producing real integrated circuits. The basic concept was to use reliable, low-cost, relatively low-technology IC processes and pack a large number of projects per wafer, with several copies of chips from each project remaining preserved. Cooperating fabricators either donated the processed waf |
https://en.wikipedia.org/wiki/Inline%20expansion | In computing, inline expansion, or inlining, is a manual or compiler optimization that replaces a function call site with the body of the called function. Inline expansion is similar to macro expansion, but occurs during compilation, without changing the source code (the text), while macro expansion occurs prior to compilation, and results in different text that is then processed by the compiler.
Inlining is an important optimization, but has complicated effects on performance. As a rule of thumb, some inlining will improve speed at very minor cost of space, but excess inlining will hurt speed, due to inlined code consuming too much of the instruction cache, and also cost significant space. A survey of the modest academic literature on inlining from the 1980s and 1990s is given in Peyton Jones & Marlow 1999.
Overview
Inline expansion is similar to macro expansion as the compiler places a new copy of the function in each place it is called. Inlined functions run a little faster than the normal functions as function-calling-overheads are saved, however, there is a memory penalty. If a function is inlined 10 times, there will be 10 copies of the function inserted into the code. Hence inlining is best for small functions that are called often. In C++ the member functions of a class, if defined within the class definition, are inlined by default (no need to use the inline keyword); otherwise, the keyword is needed. The compiler may ignore the programmer’s attempt to inline a function, mainly if it is particularly large.
Inline expansion is used to eliminate the time overhead (excess time) when a function is called. It is typically used for functions that execute frequently. It also has a space benefit for very small functions, and is an enabling transformation for other optimizations.
Without inline functions, the compiler decides which functions to inline. The programmer has little or no control over which functions are inlined and which are not. Giving this degree of control to the programmer allows for the use of application-specific knowledge in choosing which functions to inline.
Ordinarily, when a function is invoked, control is transferred to its definition by a branch or call instruction. With inlining, control drops through directly to the code for the function, without a branch or call instruction.
Compilers usually implement statements with inlining. Loop conditions and loop bodies need lazy evaluation. This property is fulfilled when the code to compute loop conditions and loop bodies is inlined. Performance considerations are another reason to inline statements.
In the context of functional programming languages, inline expansion is usually followed by the beta-reduction transformation.
A programmer might inline a function manually through copy and paste programming, as a one-time operation on the source code. However, other methods of controlling inlining (see below) are preferable, because they do not precipitate bugs arising |
https://en.wikipedia.org/wiki/Grub%20%28search%20engine%29 | Grub is an open source distributed search crawler platform.
Users of Grub could download the peer-to-peer grubclient software and let it run during their computer's idle time. The client indexed the URLs and sent them back to the main grub server in a highly compressed form. The collective crawl could then, in theory, be utilized by an indexing system, such as the one being proposed at Wikia Search. Grub was able to quickly build a large snapshot by asking thousands of clients to crawl and analyze a small portion of the web each.
Wikia has now released the entire Grub package under an open source software license. However, the old Grub clients are not functional anymore. New clients can be found on the Wikia wiki.
History
The project was started in 2000 by Kord Campbell, Igor Stojanovski, and Ledio Ago in Oklahoma City. Intellectual property rights were acquired from Grub in January 2003 for $1.3 million in cash and stock by LookSmart. For a short time the original team continued working on the project, releasing several new versions of the software, albeit under a closed license.
Operations of Grub were shut down in late 2005. On July 27, 2007, Jimmy Wales announced that Wikia, Inc., the for-profit company developing the open source search engine Wikia Search, had acquired Grub from LookSmart on July 17 for $50,000.
References
External links
Internet search engines
Free search engine software
Free web crawlers |
https://en.wikipedia.org/wiki/LookSmart | LookSmart is an American search advertising, content management, online media, and technology company. It provides search, machine learning and chatbot technologies as well as pay-per-click and contextual advertising services.
LookSmart also licenses and manages search ad networks as white-label products. It abides by the click measurement guidelines of the Interactive Advertising Bureau.
LookSmart also owns several subsidiaries, including Clickable Inc., LookSmart AdCenter, Novatech.io, ShopWiki and Syncapse.
The current CEO of LookSmart is Michael Onghai and the company is headquartered in Henderson, Nevada.
Etymology
The name "LookSmart" is a double entendre, referring to both its selective, editorially compiled directory and as a compliment to users whom the company thinks "look smart".
History
1995–1998
LookSmart was founded as Homebase in 1995 in Melbourne, Australia by husband and wife Evan Thornley and Tracy Ellery, executives of McKinsey & Company. Reader's Digest invested $5 million in the company for an 80% stake. The original concept of Homebase was to build a female and family-friendly web portal to supplement the Reader's Digest magazine. After leadership and strategy changes at Reader's Digest, which reduced RD's focus on its online business, RD wanted to shut down Homebase, which would have cost $4 million in payouts and other termination costs. The founders and former McKinsey's employee Martin Hosking instead proposed a cheaper leveraged buyout of Homebase.
On 28 October 1996, the company launched its LookSmart search engine. At launch, the search engine listed more than 85,000 sites and had a "Java-enhanced" interface. In June 1997, the search engine underwent a major redesign, dropping its original Java-based browsing system.
LookSmart was sold back to the founders as well as Martin Hosking through a leveraged buyout in 1998, with Reader's Digest providing a $1.5 million loan and retaining about a 10% equity stake. Also in 1998, a search box was added to the LookSmart search engine along with People Search, Yellow pages, Discussions and shopping search. In May 1998, the company raised $2.3 million from Amwin and $6.0 million from Cox Media Group and Macquarie Bank and was valued at $23.3 million. On 21 December 1998, LookSmart stopped accepting pornographic advertisements.
1999–2001
By 1999, the company had 500 employees and LookSmart was the twelfth most visited website worldwide with 10 million users, behind AltaVista and ahead of Snap. In early-1999, the company reached an agreement to provide directory and listing services for Microsoft for 5 years. The deal provided the company with $30 million upfront and guaranteed payments of $5 million per year. In late-March 1999, the company raised $59.6 million based on a post-money valuation of $430 million from Amerindo Investment Advisors, Citicorp Equity Capital, Cox Interactive Media, Hambrecht & Quist and others. In May 1999, LookSmart formed a strategic partnersh |
https://en.wikipedia.org/wiki/Eclipse%20%28software%29 | Eclipse is an integrated development environment (IDE) used in computer programming. It contains a base workspace and an extensible plug-in system for customizing the environment. It is the second-most-popular IDE for Java development, and, until 2016, was the most popular. Eclipse is written mostly in Java and its primary use is for developing Java applications, but it may also be used to develop applications in other programming languages via plug-ins, including Ada, ABAP, C, C++, C#, Clojure, COBOL, D, Erlang, Fortran, Groovy, Haskell, JavaScript, Julia, Lasso, Lua, NATURAL, Perl, PHP, Prolog, Python, R, Ruby (including Ruby on Rails framework), Rust, Scala, and Scheme. It can also be used to develop documents with LaTeX (via a TeXlipse plug-in) and packages for the software Mathematica. Development environments include the Eclipse Java development tools (JDT) for Java and Scala, Eclipse CDT for C/C++, and Eclipse PDT for PHP, among others.
The initial codebase originated from IBM VisualAge. The Eclipse software development kit (SDK), which includes the Java development tools, is meant for Java developers. Users can extend its abilities by installing plug-ins written for the Eclipse Platform, such as development toolkits for other programming languages, and can write and contribute their own plug-ins. Since Eclipse 3.0 (released in 2004), plug-ins are installed and managed as "bundles" using Equinox, an implementation of OSGi.
The Eclipse SDK is free and open-source software, released under the terms of the Eclipse Public License, although it is incompatible with the GNU General Public License. It was one of the first IDEs to run under GNU Classpath and it runs without problems under IcedTea.
History
Eclipse was inspired by the Smalltalk-based VisualAge family of integrated development environment (IDE) products. Although fairly successful, a major drawback of the VisualAge products was that developed code was not in a component-based software engineering model. Instead, all code for a project was held in a compressed database using SCID techniques (somewhat like a zip file but in .dat). Individual classes could not be easily accessed, certainly not outside the tool. A team primarily at the IBM Cary, NC lab developed the new product as a Java-based replacement.
In November 2001, a consortium was formed with a board of stewards to further the development of Eclipse as open-source software. It is estimated that IBM had already invested nearly $40 million by that time. The original members were Borland, IBM, Merant, QNX Software Systems, Rational Software, Red Hat, SuSE, TogetherSoft, and WebGain. The number of stewards increased to over 80 by the end of 2003. In January 2004, the Eclipse Foundation was created.
Eclipse 3.0 (released on 21 June 2004) selected the OSGi Service Platform specifications as the runtime architecture.
The Association for Computing Machinery recognized Eclipse with the 2011 ACM Software Systems Award on 26 April 201 |
https://en.wikipedia.org/wiki/List%20of%20places%20in%20Guatemala | This is a list of places in Guatemala.
List of most populous cities in Guatemala
Population data up to number 30 is based on the 2018 census.
Ancient cities and important ruins
Cancuén
Dos Pilas
El Baul
Iximche
Kaminaljuyu
Machaquila
El Mirador
La Joyanca
Mixco Viejo
Naranjo
Nakbé
Piedras Negras
Quirigua
Q'umarkaj
Tikal
Uaxactún
Natural features
Caribbean Sea
Pacific Ocean
Volcán de Agua
Volcán de Fuego
Lakes
See also
List of national parks of Guatemala
Lists of cities in Central America
References
External links
Guatemala
Cities
Guatemala |
https://en.wikipedia.org/wiki/Lifetime%20%28TV%20network%29 | Lifetime is an American basic cable channel that is part of Lifetime Entertainment Services, a subsidiary of A&E Networks, which is jointly owned by Hearst Communications and The Walt Disney Company. It features programming that is geared toward women or features women in lead roles.
, it is received by 93.8 million households in America.
History
Predecessors
There were two television channels that preceded Lifetime in its current incarnation. Daytime, originally called BETA, was launched in March 1982 by Hearst-ABC Video Services. The cable service operated four hours per day on weekdays. The service was focused on alternative women's programming. The following year, the Cable Health Network was launched as a full-time channel in June 1982 with a range of health-related programming.
Hearst/ABC-Viacom Entertainment Services
Lifetime was established on February 1, 1984, as the result of a merger of Hearst/ABC's Daytime and Viacom's Cable Health Network. A board for the new network was formed with equal representation from Hearst, ABC, and Viacom, and the board elected Thomas Burchill as the new network's first CEO. It was not an initial success, reportedly losing $36 million in its first two years of operation, and did not become profitable until 1986. The channel suffered from low viewership, with a poll reportedly finding that some TV viewers erroneously believed it carried religious content.
In 1985, Lifetime started branding itself as "Talk Television", with a nightly lineup of talk shows and call-in programs hosted by people including Regis Philbin and Ruth Westheimer (known as "Dr. Ruth"). In the process, the creators dropped the apple from the logo.
During the 1980s and early 1990s, Lifetime devoted itself on Sundays to the airing of in-depth medical programs—and advertising—for physicians under the banner of Lifetime Medical Television (LMT). As early as 1990, however, plans were floated to move LMT to another channel, with TLC and CNBC being considered. Lifetime began programming Sundays on August 1, 1993.
In 1988, Lifetime hired Patricia Fili as its head of programming. In the first three years of her tenure, she changed 60 percent of Lifetime's programming, by her own estimate. In addition to overhauling Lifetime's signature talk show, Attitudes, by hiring a new producer and refocusing it on current women's issues, Fili acquired the rights to syndicated network hits like Moonlighting and L.A. Law. She also oversaw the production of the first Lifetime movies ever made, along with carrying the final three seasons of the Blair Brown–starring dramedy The Days and Nights of Molly Dodd from NBC after the network canceled it. The network also showed movies from the portfolios of its owners, Hearst, ABC, and Viacom. In 1991, reporter Joshua Hammer stated, "Considered one of cable TV's backwaters, [...] Lifetime network was replete with annoying gabfests for housewives and recycled, long-forgotten network television series, such as Partne |
https://en.wikipedia.org/wiki/Cray | Cray Inc., a subsidiary of Hewlett Packard Enterprise, is an American supercomputer manufacturer headquartered in Seattle, Washington. It also manufactures systems for data storage and analytics. Several Cray supercomputer systems are listed in the TOP500, which ranks the most powerful supercomputers in the world.
Cray manufactures its products in part in Chippewa Falls, Wisconsin, where its founder, Seymour Cray, was born and raised. The company also has offices in Bloomington, Minnesota (which have been converted to Hewlett Packard Enterprise offices), and numerous other sales, service, engineering, and R&D locations around the world.
In 1972, the company's predecessor, Cray Research, Inc. (CRI), was founded by computer designer Seymour Cray.
In 1989, Seymour Cray formed Cray Computer Corporation (CCC), which went bankrupt in 1995.
In 1996, Cray Research was acquired by Silicon Graphics (SGI).
In 2000, Cray Inc. was formed when Tera Computer Company purchased the Cray Research Inc. business from SGI and adopted the name of its acquisition.
In 2019, the company was acquired by Hewlett Packard Enterprise for $1.3 billion.
History
Background: 1950–1972
In 1950, Seymour Cray began working in the computing field when he joined Engineering Research Associates (ERA) in Saint Paul, Minnesota. There, he helped to create the ERA 1103. ERA eventually became part of UNIVAC, and began to be phased out.
In 1960, he left the company, a few years after former ERA employees set up Control Data Corporation (CDC). He initially worked out of the CDC headquarters in Minneapolis, but grew upset by constant interruptions by managers. He eventually set up a lab in his hometown of Chippewa Falls, Wisconsin, about 85 miles to the east. Cray had a string of successes at CDC, including the CDC 6600 and CDC 7600.
Cray Research Inc. and Cray Computer Corporation: 1972–1996
When CDC ran into financial difficulties in the late 1960s, development funds for Cray's follow-on CDC 8600 became scarce. When he was told the project would have to be put "on hold" in 1972, Cray left to form his own company, Cray Research, Inc. Copying the previous arrangement, Cray kept the research and development facilities in Chippewa Falls, and put the business headquarters in Minneapolis. The company's first product, the Cray-1 supercomputer, was a major success because it was significantly faster than all other computers at the time. The first system was sold within a month for $8.8 million. Seymour Cray continued working, this time on the Cray-2, though it ended up being only marginally faster than the Cray X-MP, developed by another team at the company.
Cray soon left the CEO position to become an independent contractor. He started a new Very Large Scale Integration technology lab for the Cray-2 in Boulder, Colorado, Cray Laboratories, in 1979, which closed in 1982; undaunted, Cray later headed a similar spin-off in 1989, Cray Computer Corporation (CCC) in Colorado Springs, Colorado |
https://en.wikipedia.org/wiki/Thomas%20write%20rule | In computer science, particularly the field of databases, the Thomas write rule is a rule in timestamp-based concurrency control. It can be summarized as ignore outdated writes.
It states that, if a more recent transaction has already written the value of an object, then a less recent transaction does not need to perform its write since the more recent one will eventually overwrite it.
The Thomas write rule is applied in situations where a predefined logical order is assigned to transactions when they start. For example, a transaction might be assigned a monotonically increasing timestamp when it is created. The rule prevents changes in the order in which the transactions are executed from creating different outputs: The outputs will always be consistent with the predefined logical order.
For example, consider a database with 3 variables (A, B, C), and two atomic operations C := A (T1), and C := B (T2). Each transaction involves a read (A or B), and a write (C). The only conflict between these transactions is the write on C. The following is one possible schedule for the operations of these transactions:
If (when the transactions are created) T1 is assigned a timestamp that precedes T2 (i.e., according to the logical order, T1 comes first), then only T2's write should be visible. If, however, T1's write is executed after T2's write, then we need a way to detect this and discard the write.
One practical approach to this is to label each value with a write timestamp (WTS) that indicates the timestamp of the last transaction to modify the value. Enforcing the Thomas write rule only requires checking to see if the write timestamp of the object is greater than the time stamp of the transaction performing a write. If so, the write is discarded
In the example above, if we call TS(T) the timestamp of transaction T, and WTS(O) the write timestamp of object O, then T2's write sets WTS(C) to TS(T2). When T1 tries to write C, it sees that TS(T1) < WTS(C), and discards the write. If a third transaction T3 (with TS(T3) > TS(T2)) were to then write to C, it would get TS(T3) > WTS(C), and the write would be allowed.
References
©
Transaction processing |
https://en.wikipedia.org/wiki/Timestamp-based%20concurrency%20control | In computer science, a timestamp-based concurrency control algorithm is a non-lock concurrency control method. It is used in some databases to safely handle transactions, using timestamps.
Operation
Assumptions
Every timestamp value is unique and accurately represents an instant in time.
A higher-valued timestamp occurs later in time than a lower-valued timestamp.
Generating a timestamp
A number of different ways have been used to generate timestamp
Use the value of the system's clock at the start of a transaction as the timestamp.
Use a thread-safe shared counter that is incremented at the start of a transaction as the timestamp.
A combination of the above two methods.
Formal
Each transaction () is an ordered list of actions (). Before the transaction performs its first action (), it is marked with the current timestamp, or any other strictly totally ordered sequence: . Every transaction is also given an initially empty set of transactions upon which it depends, , and an initially empty set of old objects which it updated, .
Each object in the database is given two timestamp fields which are not used other than for concurrency control: is the time at which the value of object was last used by a transaction, is the time at which the value of the object was last updated by a transaction.
For all :
For each action :
If wishes to use the value of :
If then abort (a more recent thread has overwritten the value),
Otherwise update the set of dependencies and set ;
If wishes to update the value of :
If then abort (a more recent thread is already relying on the old value),
If then skip (the Thomas Write Rule),
Otherwise store the previous values, , set , and update the value of .
While there is a transaction in that has not ended: wait
If there is a transaction in that aborted then abort
Otherwise: commit.
To abort:
For each in
If equals then restore and
Informal
Whenever a transaction begins, it receives a timestamp. This timestamp indicates the order in which the transaction must occur, relative to the other transactions. So, given two transactions that affect the same object, the operation of the transaction with the earlier timestamp must execute before the operation of the transaction with the later timestamp. However, if the operation of the wrong transaction is actually presented first, then it is aborted and the transaction must be restarted.
Every object in the database has a read timestamp, which is updated whenever the object's data is read, and a write timestamp, which is updated whenever the object's data is changed.
If a transaction wants to read an object,
but the transaction started before the object's write timestamp it means that something changed the object's data after the transaction started. In this case, the transaction is canceled and must be restarted.
and the transaction started after the object's write timestamp, it means that it is safe to read the object. In this case, if the transaction time |
https://en.wikipedia.org/wiki/Non-lock%20concurrency%20control | In Computer Science, in the field of databases, non-lock concurrency control is a concurrency control method used in relational databases without using locking.
There are several non-lock concurrency control methods, which involve the use of timestamps on transaction to determine transaction priority:
Optimistic concurrency control
Timestamp-based concurrency control
Multiversion concurrency control
See also
Concurrency pattern
InterBase
Lock-free and wait-free algorithms
Concurrency control
Transaction processing |
https://en.wikipedia.org/wiki/Concurrency%20control | In information technology and computer science, especially in the fields of computer programming, operating systems, multiprocessors, and databases, concurrency control ensures that correct results for concurrent operations are generated, while getting those results as quickly as possible.
Computer systems, both software and hardware, consist of modules, or components. Each component is designed to operate correctly, i.e., to obey or to meet certain consistency rules. When components that operate concurrently interact by messaging or by sharing accessed data (in memory or storage), a certain component's consistency may be violated by another component. The general area of concurrency control provides rules, methods, design methodologies, and theories to maintain the consistency of components operating concurrently while interacting, and thus the consistency and correctness of the whole system. Introducing concurrency control into a system means applying operation constraints which typically result in some performance reduction. Operation consistency and correctness should be achieved with as good as possible efficiency, without reducing performance below reasonable levels. Concurrency control can require significant additional complexity and overhead in a concurrent algorithm compared to the simpler sequential algorithm.
For example, a failure in concurrency control can result in data corruption from torn read or write operations.
Concurrency control in databases
Comments:
This section is applicable to all transactional systems, i.e., to all systems that use database transactions (atomic transactions; e.g., transactional objects in Systems management and in networks of smartphones which typically implement private, dedicated database systems), not only general-purpose database management systems (DBMSs).
DBMSs need to deal also with concurrency control issues not typical just to database transactions but rather to operating systems in general. These issues (e.g., see Concurrency control in operating systems below) are out of the scope of this section.
Concurrency control in Database management systems (DBMS; e.g., Bernstein et al. 1987, Weikum and Vossen 2001), other transactional objects, and related distributed applications (e.g., Grid computing and Cloud computing) ensures that database transactions are performed concurrently without violating the data integrity of the respective databases. Thus concurrency control is an essential element for correctness in any system where two database transactions or more, executed with time overlap, can access the same data, e.g., virtually in any general-purpose database system. Consequently, a vast body of related research has been accumulated since database systems emerged in the early 1970s. A well established concurrency control theory for database systems is outlined in the references mentioned above: serializability theory, which allows to effectively design and analyze concurrency control met |
https://en.wikipedia.org/wiki/Executable | In computing, executable code, an executable file, or an executable program, sometimes simply referred to as an executable or binary, causes a computer "to perform indicated tasks according to encoded instructions", as opposed to a data file that must be interpreted (parsed) by a program to be meaningful.
The exact interpretation depends upon the use. "Instructions" is traditionally taken to mean machine code instructions for a physical CPU. In some contexts, a file containing scripting instructions (such as bytecode) may also be considered executable.
Generation of executable files
Executable files can be hand-coded in machine language, although it is far more convenient to develop software as source code in a high-level language that can be easily understood by humans. In some cases, source code might be specified in assembly language instead, which remains human-readable while being closely associated with machine code instructions.
The high-level language is compiled into either an executable machine code file or a non-executable machine code – object file of some sort; the equivalent process on assembly language source code is called assembly. Several object files are linked to create the executable. Object files -- executable or not -- are typically stored in a container format, such as Executable and Linkable Format (ELF) or Portable Executable (PE) which is operating system-specific. This gives structure to the generated machine code, for example dividing it into sections such as .text (executable code), .data (initialized global and static variables), and .rodata (read-only data, such as constants and strings).
Executable files typically also include a runtime system, which implements runtime language features (such as task scheduling, exception handling, calling static constructors and destructors, etc.) and interactions with the operating system, notably passing arguments, environment, and returning an exit status, together with other startup and shutdown features such as releasing resources like file handles. For C, this is done by linking in the crt0 object, which contains the actual entry point and does setup and shutdown by calling the runtime library.
Executable files thus normally contain significant additional machine code beyond that directly generated from the specific source code. In some cases, it is desirable to omit this, for example for embedded systems development, or simply to understand how compilation, linking, and loading work. In C, this can be done by omitting the usual runtime, and instead explicitly specifying a linker script, which generates the entry point and handles startup and shutdown, such as calling main to start and returning exit status to the kernel at the end.
Execution
In order to be executed by the system (such as an operating system, , or boot loader), an executable file must conform to the system's application binary interface (ABI). In simple interfaces, a file is executed by loading |
https://en.wikipedia.org/wiki/Lagrange%20polynomial | In numerical analysis, the Lagrange interpolating polynomial is the unique polynomial of lowest degree that interpolates a given set of data.
Given a data set of coordinate pairs with the are called nodes and the are called values. The Lagrange polynomial has degree and assumes each value at the corresponding node,
Although named after Joseph-Louis Lagrange, who published it in 1795, the method was first discovered in 1779 by Edward Waring. It is also an easy consequence of a formula published in 1783 by Leonhard Euler.
Uses of Lagrange polynomials include the Newton–Cotes method of numerical integration, Shamir's secret sharing scheme in cryptography, and Reed–Solomon error correction in coding theory.
For equispaced nodes, Lagrange interpolation is susceptible to Runge's phenomenon of large oscillation.
Definition
Given a set of nodes , which must all be distinct, for indices , the Lagrange basis for polynomials of degree for those nodes is the set of polynomials each of degree which take values if and . Using the Kronecker delta this can be written Each basis polynomial can be explicitly described by the product:
Notice that the numerator has roots at the nodes while the denominator scales the resulting polynomial so that
The Lagrange interpolating polynomial for those nodes through the corresponding values is the linear combination:
Each basis polynomial has degree , so the sum has degree , and it interpolates the data because
The interpolating polynomial is unique. Proof: assume the polynomial of degree interpolates the data. Then the difference is zero at distinct nodes But the only polynomial of degree with more than roots is the constant zero function, so or
Barycentric form
Each Lagrange basis polynomial can be rewritten as the product of three parts, a function common to every basis polynomial, a node-specific constant (called the barycentric weight), and a part representing the displacement from to :
By factoring out from the sum, we can write the Lagrange polynomial in the so-called first barycentric form:
If the weights have been pre-computed, this requires only operations compared to for evaluating each Lagrange basis polynomial individually.
The barycentric interpolation formula can also easily be updated to incorporate a new node by dividing each of the , by and constructing the new as above.
For any because the constant function is the unique polynomial of degree interpolating the data We can thus further simplify the barycentric formula by dividing
This is called the second form or true form of the barycentric interpolation formula.
This second form has advantages in computation cost and accuracy: it avoids evaluation of ; the work to compute each term in the denominator has already been done in computing and so computing the sum in the denominator costs only addition operations; for evaluation points which are close to one of the nodes , catastrophic cancela |
https://en.wikipedia.org/wiki/Conservative%20two-phase%20locking | In computer science, conservative two-phase locking (C2PL) is a locking method used in DBMS and relational databases.
Conservative 2PL prevents deadlocks.
The difference between 2PL and C2PL is that C2PL's transactions obtain all the locks they need before the transactions begin. This is to ensure that a transaction that already holds some locks will not block waiting for other locks.
In heavy lock contention, C2PL reduces the time locks are held on average, relative to 2PL and Strict 2PL, because transactions that hold locks are never blocked.
In light lock contention, C2PL holds more locks than is necessary, because it is hard to tell what locks will be needed in the future, thus leads to higher overhead.
Also, a transaction will not even obtain any locks if it cannot obtain all the locks it needs in its initial request. Furthermore, each transaction needs to declare its read and write set (data items to be read/written during transaction), which is not always possible. Because of these limitations, C2PL is not used very frequently.
Concurrency control |
https://en.wikipedia.org/wiki/Self-modifying%20code | In computer science, self-modifying code (SMC or SMoC) is code that alters its own instructions while it is executing – usually to reduce the instruction path length and improve performance or simply to reduce otherwise repetitively similar code, thus simplifying maintenance. The term is usually only applied to code where the self-modification is intentional, not in situations where code accidentally modifies itself due to an error such as a buffer overflow.
Self-modifying code can involve overwriting existing instructions or generating new code at run time and transferring control to that code.
Self-modification can be used as an alternative to the method of "flag setting" and conditional program branching, used primarily to reduce the number of times a condition needs to be tested.
The method is frequently used for conditionally invoking test/debugging code without requiring additional computational overhead for every input/output cycle.
The modifications may be performed:
only during initialization – based on input parameters (when the process is more commonly described as software 'configuration' and is somewhat analogous, in hardware terms, to setting jumpers for printed circuit boards). Alteration of program entry pointers is an equivalent indirect method of self-modification, but requiring the co-existence of one or more alternative instruction paths, increasing the program size.
throughout execution ("on the fly") – based on particular program states that have been reached during the execution
In either case, the modifications may be performed directly to the machine code instructions themselves, by overlaying new instructions over the existing ones (for example: altering a compare and branch to an unconditional branch or alternatively a 'NOP').
In the IBM System/360 architecture, and its successors up to z/Architecture, an EXECUTE (EX) instruction logically overlays the second byte of its target instruction with the low-order 8 bits of register 1. This provides the effect of self-modification although the actual instruction in storage is not altered.
Application in low and high level languages
Self-modification can be accomplished in a variety of ways depending upon the programming language and its support for pointers and/or access to dynamic compiler or interpreter 'engines':
overlay of existing instructions (or parts of instructions such as opcode, register, flags or addresses) or
direct creation of whole instructions or sequences of instructions in memory
creating or modification of source code statements followed by a 'mini compile' or a dynamic interpretation (see eval statement)
creating an entire program dynamically and then executing it
Assembly language
Self-modifying code is quite straightforward to implement when using assembly language. Instructions can be dynamically created in memory (or else overlaid over existing code in non-protected program storage), in a sequence equivalent to the ones that a standard co |
https://en.wikipedia.org/wiki/Domain%20relational%20calculus | In computer science, domain relational calculus (DRC) is a calculus that was introduced by Michel Lacroix and Alain Pirotte as a declarative database query language for the relational data model.
In DRC, queries have the form:
where each Xi is either a domain variable or constant, and denotes a DRC formula. The result of the query is the set of tuples X1 to Xn that make the DRC formula true.
This language uses the same operators as tuple calculus,
the logical connectives ∧ (and), ∨ (or) and ¬ (not). The existential quantifier (∃) and the universal quantifier (∀) can be used to bind the variables.
Its computational expressiveness is equivalent to that of relational algebra.
Examples
Let (A, B, C) mean (Rank, Name, ID) in the Enterprise relation
and let (D, E, F) mean (Name, DeptName, ID) in the Department relation
All captains of the starship USS Enterprise:
In this example, A, B, C denotes both the result set and a set in the table Enterprise.
Names of Enterprise crew members who are in Stellar Cartography:
In this example, we're only looking for the name, and that's B. The condition F = C is a requirement that describes the intersection of Enterprise crew members AND members of the Stellar Cartography Department.
An alternate representation of the previous example would be:
In this example, the value of the requested F domain is directly placed in the formula and the C domain variable is re-used in the query for the existence of a department, since it already holds a crew member's ID.
See also
Relational calculus
References
External links
DES – An educational tool for working with Domain Relational Calculus and other formal languages
WinRDBI – An educational tool for working with Domain Relational Calculus and other formal languages
Relational model
Logical calculi |
https://en.wikipedia.org/wiki/Write%E2%80%93read%20conflict | In computer science, in the field of databases, write–read conflict, also known as reading uncommitted data, is a computational anomaly associated with interleaved execution of transactions.
Given a schedule S
T2 could read a database object A, modified by T1 which hasn't committed. This is a dirty or inconsistent read.
T1 may write some value into A which makes the database inconsistent. It is possible that interleaved execution can expose this inconsistency and lead to an inconsistent final database state, violating ACID rules.
Strict 2PL overcomes this inconsistency by locking T2 out from performing a Read/Write on A. Note however that Strict 2PL can have a number of drawbacks, such as the possibility of deadlocks.
See also
Concurrency control
Read–write conflict
Write–write conflict
References
Data management
Transaction processing |
https://en.wikipedia.org/wiki/Write%E2%80%93write%20conflict | In computer science, in the field of databases, write–write conflict, also known as overwriting uncommitted data is a computational anomaly associated with interleaved execution of transactions.
Given a schedule S
note that there is no read in this schedule. The writes are called blind writes.
We have a lost update. Any attempts to make this schedule serial would give off two different results (either T1's version of A and B is shown, or T2's version of A and B is shown), and would not be the same as the above schedule. This schedule would not be serializable.
Strict 2PL overcomes this inconsistency by locking T1 out from B. Unfortunately, deadlocks are something Strict 2PL does not overcome all the time.
See also
Concurrency control
Read–write conflict
Write–read conflict
References
Data management
Transaction processing |
https://en.wikipedia.org/wiki/Read%E2%80%93write%20conflict | In computer science, in the field of databases, read–write conflict, also known as unrepeatable reads, is a computational anomaly associated with interleaved execution of transactions.
Given a schedule S
In this example, T1 has read the original value of A, and is waiting for T2 to finish. T2 also reads the original value of A, overwrites A, and commits.
However, when T1 reads from A, it discovers two different versions of A, and T1 would be forced to abort, because T1 would not know what to do. This is an unrepeatable read. This could never occur in a serial schedule, in which each transaction executes in its entirety before another begins. Strict two-phase locking (Strict 2PL) or Serializable Snapshot Isolation (SSI) prevent this conflict.
Real-world example
Alice and Bob are using a website to book tickets for a specific show. Only one ticket is left for the specific show. Alice signs on first to see that only one ticket is left, and finds it expensive. Alice takes time to decide. Bob signs on and also finds one ticket left, and orders it instantly. Bob purchases and logs off. Alice decides to buy a ticket, to find there are no tickets. This is a typical read-write conflict situation.
See also
Concurrency control
Write–read conflict
Write–write conflict
Data management
Transaction processing |
https://en.wikipedia.org/wiki/10BROAD36 | 10BROAD36 is an obsolete computer network standard in the Ethernet family. It was developed during the 1980s and specified in IEEE 802.3b-1985. The Institute of Electrical and Electronics Engineers standards committee IEEE 802 published the standard that was ratified in 1985 as an additional section 11 to the base Ethernet standard. It was also issued as ISO/IEC 8802-3 in 1989.
The standard supports 10 Mbit/s Ethernet signals over standard 75 ohm cable television (CATV) cable over a 3600-meter range. 10BROAD36 modulates its data onto a higher frequency carrier signal, much as an audio signal would modulate a carrier signal to be transmitted in a radio station. In telecommunications engineering, this is a broadband signaling technique. Broadband provides several advantages over the baseband signal used, for instance in 10BASE5. Range is greatly extended (3600 meters, versus 500 meters for 10BASE5), and multiple signals can be carried on the same cable. 10BROAD36 can even share a cable with standard television channels.
Deployment
10BROAD36 was less successful than its contemporaries because of the high equipment complexity (and cost) associated with it. The individual stations are much more expensive due to the extra radio frequency circuitry involved; however the primary extra complexity comes from the fact that 10BROAD36 is unidirectional. Signals can only travel one direction along the line, so head-end stations must be present on the line to repeat the signals (ensuring that no packets travel through the line indefinitely) on either another, backwards direction frequency on the same line, or another line entirely. This also increases latency and prevents bidirectional signal flow.
The extra complexity outweighed the advantage of reusability of CATV technology for the intended campus networks and metropolitan area networks. An installer at Boston University using the Ungermann-Bass product noted that no installers understood both the digital and analog aspects of the system.
In wide area networks it was quickly replaced by fiber-optic communication alternatives, such as 100BASE-FX (which provided ten times the data rate). Interest in cable modems was revived for residential Internet access, through later technologies such as the Data Over Cable Service Interface Specification (DOCSIS) in the 1990s.
See also
10PASS-TS
Notes
References
External links
Ethernet standards |
https://en.wikipedia.org/wiki/IBM%20PS/2 | The Personal System/2 or PS/2 is IBM's second generation of personal computers. Released in 1987, it officially replaced the IBM PC, XT, AT, and PC Convertible in IBM's lineup. Many of the PS/2's innovations, such as the 16550 UART (serial port), 1440 KB 3.5-inch floppy disk format, 72-pin SIMMs, the PS/2 port, and the VGA video standard, went on to become standards in the broader PC market.
The PS/2 line was created by IBM partly in an attempt to recapture control of the PC market by introducing the advanced yet proprietary Micro Channel architecture (MCA) on higher-end models. These models were in the strange position of being incompatible with the hardware standards previously established by IBM and adopted in the IBM PC compatible industry. IBM's initial PS/2 computers were popular with target market corporate buyers, and by September 1988, IBM reported that it had sold 3 million PS/2 machines. This was only 18 months after the new range had been introduced.
Most major PC manufacturers balked at IBM's licensing terms for MCA-compatible hardware, particularly the per-machine royalties. In 1992, Macworld stated that "IBM lost control of its own market and became a minor player with its own technology." IBM officially retired the PS/2 line in July 1995.
The OS/2 operating system was announced at the same time as the PS/2 line and was intended to be the primary operating system for models with Intel 80286 or later processors. However, at the time of the first shipments, only IBM PC DOS 3.3 was available. OS/2 1.0 (text-mode only) and Microsoft's Windows 2.0 became available several months later. IBM also released AIX PS/2, a UNIX operating system for PS/2 models with Intel 386 or later processors.
Technology
IBM's PS/2 was designed to remain software compatible with their PC/AT/XT line of computers upon which the large PC clone market was built, but the hardware was quite different. PS/2 had two BIOSes: one named ABIOS (Advanced BIOS) which provided a new protected mode interface and was used by OS/2, and CBIOS (Compatible BIOS) which was included to be software compatible with the PC/XT/AT. CBIOS was so compatible that it even included Cassette BASIC. While IBM did not publish the BIOS source code, it did promise to publish BIOS entry points.
Micro Channel architecture
With certain models to the IBM PS/2 line, Micro Channel Architecture (MCA) was also introduced. MCA was conceptually similar to the channel architecture of the IBM System/360 mainframes. MCA was technically superior to ISA and allowed for higher speed communications within the system. The majority of MCA's features would be seen in later buses with the exception of: streaming-data procedure, channel-check reporting, error logging and internal bus-level video pass-through for devices like the IBM 8514. Transfer speeds were on par with the much later PCI standard. MCA allowed one-to-one, card to card, and multi-card to processor simultaneous transaction management which is a |
https://en.wikipedia.org/wiki/ESDI | ESDI may refer to:
ESDi School of Design, at University Ramon Llull, Barcelona, Spain
Enhanced Small Disk Interface, a computer disk interface
European Security and Defence Identity, a European initiative in NATO overseen by the Western European Union
Escola Superior de Desenho Industrial, at Rio de Janeiro State University, Brazil |
https://en.wikipedia.org/wiki/Linux%20Gazette | The Linux Gazette was a monthly self-published Linux computing webzine, published between July 1995 and June 2011. Its content was published under the Open Publication License.
History
It was started in July 1995 by John M. Fisk as a free service. He went on to pursue his studies and become a medical doctor. At Mr. Fisk's request, the publication was sponsored and managed by SSC (Specialized System Consultants, who at that time were also publishers of Linux Journal). The content was always provided by volunteers, including most of the editorial oversight.
After those years, the volunteer staff and the management of SSC had a schism (see Bifurcation below). Both the volunteer-run magazine and the magazine run by SSC has been closed down.
One way Linux Gazette differed from other, similar, webzines (and magazines) was The Answer Gang. In addition to providing a regular page devoted to questions and answers, questions to The Answer Gang were answered on a mailing list, and the subsequent conversations are edited and published as conversations. This started with an arrangement between Marjorie Richardson and Jim Dennis (whom she dubbed "The Answer Guy"). She'd forward questions to him; he'd answer them to the original querent and copy her on the reply; then, she'd gather up all of those, and include them in the monthly help desk column.
With its motto, "Making Linux just a little more fun", the magazine always had a finger on the pulse of Linux's open, collaborating, and sharing culture.
The last issue (#186) was published in June 2011.
Bifurcation
Fisk transferred the management of the Linux Gazette to SSC (under Phil Hughes) in 1996 in order to pursue medical studies, on the understanding that the publication would continue to be open, free, and non-commercial.
In October 2003, the Linux Gazette split into two competing groups. The staff of LinuxGazette.net, however, said that their decision to start their own version of Linux Gazette was due to several factors: SSC's assertion that Linux Gazette would no longer be edited or released in monthly issues, as well as the removal of material from older issues without notifying the authors.
SSC attempted to assert trademark claims over the publication. LinuxGazette.net contributing editor Rick Moen, however, addressed this claim in an article for LinuxGazette.net:
The very same day it received our notice of the magazine's departure, SSC, Inc. suddenly filed a US $300 fee and trademark application #78319880 with the USA Patent and Trademark Office (USPTO), requesting registration of the name "Linux Gazette" as a service mark. On that form, SSC certified that it had used the mark in commerce starting August 1, 1996. ... SSC's recent legal claim to hegemony over the name "Linux Gazette" strikes us as outrageously unmerited, and cheeky.
Starting May 30, 2004, the US Patent and Trademark Office (USPTO) Trademark Electronic Business Center's TDR (Text Document Retrieval) online record showed a U |
https://en.wikipedia.org/wiki/Multiversion%20concurrency%20control | Multiversion concurrency control (MCC or MVCC), is a concurrency control method commonly used by database management systems to provide concurrent access to the database and in programming languages to implement transactional memory.
Description
Without concurrency control, if someone is reading from a database at the same time as someone else is writing to it, it is possible that the reader will see a half-written or inconsistent piece of data. For instance, when making a wire transfer between two bank accounts if a reader reads the balance at the bank when the money has been withdrawn from the original account and before it was deposited in the destination account, it would seem that money has disappeared from the bank. Isolation is the property that provides guarantees in the concurrent accesses to data. Isolation is implemented by means of a concurrency control protocol. The simplest way is to make all readers wait until the writer is done, which is known as a read-write lock. Locks are known to create contention especially between long read transactions and update transactions. MVCC aims at solving the problem by keeping multiple copies of each data item. In this way, each user connected to the database sees a snapshot of the database at a particular instant in time. Any changes made by a writer will not be seen by other users of the database until the changes have been completed (or, in database terms: until the transaction has been committed.)
When an MVCC database needs to update a piece of data, it will not overwrite the original data item with new data, but instead creates a newer version of the data item. Thus there are multiple versions stored. The version that each transaction sees depends on the isolation level implemented. The most common isolation level implemented with MVCC is snapshot isolation. With snapshot isolation, a transaction observes a state of the data as of when the transaction started.
MVCC provides point-in-time consistent views. Read transactions under MVCC typically use a timestamp or transaction ID to determine what state of the DB to read, and read these versions of the data. Read and write transactions are thus isolated from each other without any need for locking. However, despite locks being unnecessary, they are used by some MVCC databases such as Oracle. Writes create a newer version, while concurrent reads access an older version.
MVCC introduces the challenge of how to remove versions that become obsolete and will never be read. In some cases, a process to periodically sweep through and delete the obsolete versions is implemented. This is often a stop-the-world process that traverses a whole table and rewrites it with the last version of each data item. PostgreSQL can use this approach with its VACUUM FREEZE process. Other databases split the storage blocks into two parts: the data part and an undo log. The data part always keeps the last committed version. The undo log enables the recreation of older |
https://en.wikipedia.org/wiki/Polymorphic%20code | In computing, polymorphic code is code that uses a polymorphic engine to mutate while keeping the original algorithm intact - that is, the code changes itself every time it runs, but the function of the code (its semantics) will not change at all. For example, the simple math expressions 3+1 and 6-2 both achieve the same result, yet run with different machine code in a CPU. This technique is sometimes used by computer viruses, shellcodes and computer worms to hide their presence.
Encryption is the most common method to hide code. With encryption, the main body of the code (also called its payload) is encrypted and will appear meaningless. For the code to function as before, a decryption function is added to the code. When the code is executed, this function reads the payload and decrypts it before executing it in turn.
Encryption alone is not polymorphism. To gain polymorphic behavior, the encryptor/decryptor pair is mutated with each copy of the code. This allows different versions of some code which all function the same.
Malicious code
Most anti-virus software and intrusion detection systems (IDS) attempt to locate malicious code by searching through computer files and data packets sent over a computer network. If the security software finds patterns that correspond to known computer viruses or worms, it takes appropriate steps to neutralize the threat. Polymorphic algorithms make it difficult for such software to recognize the offending code because it constantly mutates.
Malicious programmers have sought to protect their encrypted code from this virus-scanning strategy by rewriting the unencrypted decryption engine (and the resulting encrypted payload) each time the virus or worm is propagated. Anti-virus software uses sophisticated pattern analysis to find underlying patterns within the different mutations of the decryption engine, in hopes of reliably detecting such malware.
Emulation may be used to defeat polymorphic obfuscation by letting the malware demangle itself in a virtual environment before utilizing other methods, such as traditional signature scanning. Such a virtual environment is sometimes called a sandbox. Polymorphism does not protect the virus against such emulation if the decrypted payload remains the same regardless of variation in the decryption algorithm. Metamorphic code techniques may be used to complicate detection further, as the virus may execute without ever having identifiable code blocks in memory that remains constant from infection to infection.
The first known polymorphic virus was written by Mark Washburn. The virus, called 1260, was written in 1990. A better-known polymorphic virus was created in 1992 by the hacker Dark Avenger as a means of avoiding pattern recognition from antivirus software. A common and very virulent polymorphic virus is the file infecter Virut.
Example
This example is not really a polymorphic code but will serve as an introduction to the world of encryption via the XOR operat |
https://en.wikipedia.org/wiki/SNP | SNP may refer to:
Computing
SNP (complexity), in theoretical computer science
SNP file format, for Microsoft Access reports
Scalable Networking Pack, to extend Microsoft Windows Server 2003
Secure Network Programming, a prototype Internet protocol and API
SnP file or Touchstone file, an electrical circuit simulation data format
Entertainment
The Sunday Night Project, a British television show
"SNP (Shining Nature Purity)", a 2020 song by W24
Places
Six Nations Polytechnic, post-secondary institution in Ontario, Canada
State Nature Preserves of the Kentucky State Nature Preserves Commission
SNP Stadium, Banská Bystrica, Slovakia
Political parties
Scottish National Party, Scotland
Seychelles National Party
Socialist People's Party of Montenegro ()
Serbian People's Party (), Serbia
Science
Single-nucleotide polymorphism, a DNA sequence variation
Sodium nitroprusside, a peripheral vasodilator
Other uses
Sinopec's NYSE ticker symbol
Social networking potential in marketing research
Special needs plan, a Medicare Advantage plan
See also |
https://en.wikipedia.org/wiki/Basic%20block | In compiler construction, a basic block is a straight-line code sequence with no branches in except to the entry and no branches out except at the exit. This restricted form makes a basic block highly amenable to analysis. Compilers usually decompose programs into their basic blocks as a first step in the analysis process. Basic blocks form the vertices or nodes in a control-flow graph.
Definition
The code in a basic block has:
One entry point, meaning that no code within it is the destination of a jump instruction anywhere in the program.
One exit point, meaning that only the last instruction can cause the program to begin executing code in a different basic block.
Under these circumstances, whenever the first instruction in a basic block is executed, the rest of the instructions are necessarily executed exactly once and in order.
The code may be source code, assembly code, or some other sequence of instructions.
More formally, a sequence of instructions forms a basic block if:
The instruction in each position dominates (always executes before) all those in later positions.
No other instruction executes between two instructions in the sequence.
This definition is more general than the intuitive one in some ways. For example, it allows unconditional jumps to labels not targeted by other jumps. This definition embodies the properties that make basic blocks easy to work with when constructing an algorithm.
The blocks to which control may transfer after reaching the end of a block are called that block's successors, while the blocks from which control may have come when entering a block are called that block's predecessors. The start of a basic block may be jumped to from more than one location.
Creation algorithm
The algorithm for generating basic blocks from a listing of code is simple: the analyser scans over the code, marking block boundaries, which are instructions that may either begin or end a block because they either transfer control or accept control from another point. Then, the listing is simply "cut" at each of these points, and basic blocks remain.
Note that this method does not always generate maximal basic blocks, by the formal definition, but they are usually sufficient (maximal basic blocks are basic blocks that cannot be extended by including adjacent blocks without violating the definition of a basic block).
Input: A sequence of instructions (mostly three-address code).
Output: A list of basic blocks with each three-address statement in exactly one block.
Identify the leaders in the code. Leaders are instructions that come under any of the following 3 categories:
It is the first instruction. The first instruction is a leader.
The target of a conditional or an unconditional goto/jump instruction is a leader.
The instruction that immediately follows a conditional or an unconditional goto/jump instruction is a leader.
Starting from a leader, the set of all following instructions until and not including the next lea |
https://en.wikipedia.org/wiki/Binary%20translation | In computing, binary translation is a form of binary recompilation where sequences of instructions are translated from a source instruction set to the target instruction set. In some cases such as instruction set simulation, the target instruction set may be the same as the source instruction set, providing testing and debugging features such as instruction trace, conditional breakpoints and hot spot detection.
The two main types are static and dynamic binary translation. Translation can be done in hardware (for example, by circuits in a CPU) or in software (e.g. run-time engines, static recompiler, emulators).
Motivation
Binary translation is motivated by a lack of a binary for a target platform, the lack of source code to compile for the target platform, or otherwise difficulty in compiling the source for the target platform.
Statically-recompiled binaries run potentially faster than their respective emulated binaries, as the emulation overhead is removed. This is similar to the difference in performance between interpreted and compiled programs in general.
Static binary translation
A translator using static binary translation aims to convert all of the code of an executable file into code that runs on the target architecture without having to run the code first, as is done in dynamic binary translation. This is very difficult to do correctly, since not all the code can be discovered by the translator. For example, some parts of the executable may be reachable only through indirect branches, whose value is known only at run-time.
One such static binary translator uses universal superoptimizer peephole technology (developed by Sorav Bansal and Alex Aiken from Stanford University) to perform efficient translation between possibly many source and target pairs, with considerably low development costs and high performance of the target binary. In experiments of PowerPC-to-x86 translations, some binaries even outperformed native versions, but on average they ran at two-thirds of native speed.
Examples for static binary translations
Honeywell provided a program called the Liberator for their Honeywell 200 series of computers; it could translate programs for the IBM 1400 series of computers into programs for the Honeywell 200 series.
In 2014, an ARM architecture version of the 1998 video game StarCraft was generated by static recompilation and additional reverse engineering of the original x86 version.
The Pandora handheld community was capable of developing the required tools on their own and achieving such translations successfully several times.
For instance, a successful x86-to-x64 static recompilation was generated for the procedural terrain generator of the video game Cube World in 2014.
Another example is the NES-to-x86 statically recompiled version of the videogame Super Mario Bros. which was generated under usage of LLVM in 2013.
In 2004 Scott Elliott and Phillip R. Hutchinson at Nintendo developed a tool to generate "C" code fr |
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