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RAM (Random Access Memory) is a hardware component

Computing is usually defined as the activity of using and improving computer technology, computer hardware and software. It is the computer-specific part of information technology. Computer science (or computing science) is the study and the science of the theoretical foundations of information and computation and their implementation and application in computer systems.

Computing Curricula 2005^[1] defined computing:

In a general way, we can define computing to mean any goal-oriented activity requiring, benefiting from, or creating computers. Thus, computing includes designing and building hardware and software systems for a wide range of purposes; processing, structuring, and managing various kinds of information; doing scientific studies using computers; making computer systems behave intelligently; creating and using communications and entertainment media; finding and gathering information relevant to any particular purpose, and so on. The list is virtually endless, and the possibilities are vast.

A computer is a machine that manipulates data according to a set of instructions called a computer program. The program has an executable form that the computer can use directly to execute the instructions. The same program in its human-readable source code form, enables a programmer to study and develop the algorithm. Because the instructions can be carried out in different types of computers, a single set of source instructions converts to machine instructions according to the central processing unit type.

The execution process carries out the instructions in a computer program. Instructions express the computations performed by the computer. They trigger sequences of simple actions on the executing machine. Those actions produce effects according to the semantics of the instructions.

Computer programming in general is the process of writing, testing, debugging, and maintaining the source code and documentation of computer programs. This source code is written in a programming language, which is an artificial language, restrictive, demanding, and unforgiving to humans but easily translated by the computer. The purpose of programming is to invoke the desired behaviour (customization) from the machine. The process of writing high quality source code requires knowledge of both the application's domain and the computer science domain. The highest quality software is thus developed by a team of various domain experts, each person a specialist in some area of development. But the term programmer may apply to a range of program quality, from hacker to open source contributor to professional. And a single programmer could do most or all of the computer programming needed to generate the proof of concept to launch a new "killer" application.

Definitions

The term computing, more commonly known as computer science, has sometimes been narrowly defined, as in a 1989 ACM report on Computing as a Discipline^[2]:

The discipline of computing is the systematic study of algorithmic processes that describe and transform information: their theory, analysis, design, efficiency, implementation, and application. The fundamental question underlying all computing is 'What can be (efficiently) automated?

Computing Curricula 2005^[1] also recognizes that the meaning of computing depends on the context:-

Computing also has other meanings that are more specific, based on the context in which the term is used. For example, an information systems specialist will view computing somewhat differently from a software engineer. Regardless of the context, doing computing well can be complicated and difficult. Because society needs people to do computing well, we must think of computing not only as a profession but also as a discipline.

The term computing is also synonymous with counting and calculating. In earlier times it was used in reference to mechanical computing machines.

A computer is an electronic device that sends and receives data. The most common examples are microcomputers, minicomputers and mainframe computers. Other examples include mobile phones, mp3 players, satellites, video game consoles, virtually anything that can send and receive data.

Science and theory

• Computer science
• Theory of computation
• Computational models
• Digital Bibliography & Library Project, as of July 2007, lists over 910 000 bibliographic entries on computer science and several thousand links to the home pages of computer scientists
• Scientific computing
• Metacomputing
• Topological computing
• Autonomic Computing

Hardware

See information processor for a high-level block diagram.

Instruction-level taxonomies

After the commoditization of memory, attention turned to optimizing CPU performance at the instruction level. Various methods of speeding up the fetch-execute cycle include:

• designing instruction set architectures with simpler, faster instructions: RISC as opposed to CISC
• Superscalar instruction execution
• VLIW architectures, which make parallelism explicit

Software

• Software engineering
• Computer programming
• Computational
• Software patent
• Firmware
• Operating systems
• Application Software
  • Databases
  • Geographic information system
  • Spreadsheet
  • Word processor
• Programming languages
  • interpreters
  • compilers
• Speech recognition

History of computing

• History of computing hardware from the tally stick to the quantum computer
• History of computer science
• Punch Card
• Unit record equipment
• IBM 700/7000 series
• IBM 1400 series
• System/360
• Early IBM disk storage

Business computing

Human factors

• Accessible computing
• Human-computer interaction
• Human-centered computing

Computer network

Wired and wireless computer network

• Types
  • Wide Area Network
  • Metropolitan Area Network
  • City Area Network
  • Village Area Network
  • Local Area Network
    • Wireless Local Area Network
• Mesh networking
• Collaborative workspace
• Internet
• Network Management

Computing technology based wireless networking (CbWN)

The main of goal of CbWN is to optimize the system performance of the flexible wireless network.

• Source coding
  • Codebook design for side information based transmission techniques such as Precoding
  • Wyner-Ziv coding for Cooperative wireless communications

• Security
  • Dirty paper coding for cooperative multiple antenna or user precoding

• Intelligence
  • Game theory for wireless networking
  • Cognitive communications
  • Flexible sectorization, Beamforming and SDMA

• Software
  • Software defined radio (SDR)
  • Programmable air-interface
  • Downloadable algorithm: e.g., downloadable codebook for Precoding

Computer security

Data

Numeric data

• integral data types - bit, byte, etc.
• real data types:
  • Floating point (Single precision, Double precision, etc.)
  • Fixed point
  • Rational number
• Decimal
  • Binary-coded decimal (BCD)
  • Excess-3 BCD (XS-3)
  • Biquinary-coded decimal
• representation: Binary - Octal - Decimal - Hexadecimal (hex)
• Computer mathematics - Computer numbering formats -

Character data

• storage: Character - String - Plaintext
  • representation: ASCII - Unicode - Multibyte - EBCDIC (Widecharacter, Multicharacter) - Fieldata - Baudot

Other data topics

• Data compression
• Digital signal processing
• Image processing
• Indexed
• Data management
• Routing
• Data Protection Act

Mechatronics

• Punch card
• Key punch
• Unit record equipment

Classes of computers

Companies - current

Companies - historic

• Acorn, bought by Olivetti
• Amdahl Corporation, bought by Fujitsu
• Bendix Corporation
• Burroughs Corporation, merged with Sperry to become Unisys
• Compaq, bought by Hewlett-Packard
• Control Data
• Cray
• Data General
• Digital Equipment Corporation, bought by Compaq, in turn bought by Hewlett-Packard
• Digital Research - produced system software for early Intel microprocessor-based computers
• English Electric Company
• Ferranti
• General Electric, computer division bought by Honeywell, then Bull
• Honeywell, computer division bought by Bull
• ICL
• Leo
• Lisp Machines, Inc.
• Marconi
• Micro Instrumentation and Telemetry Systems produced the first widely sold microcomputer system (kit and assembled)
• Nixdorf Computer, bought by Siemens
• Olivetti
• Osborne
• Packard Bell
• Prime Computer
• Raytheon
• Royal McBee
• RCA
• Scientific Data Systems, sold to Xerox
• Siemens
• Sinclair Research, created the Sinclair ZX Spectrum, ZX80 and ZX81
• Southweat Technical products Corporation produced microcomputers systems (kit and assembled), peripherals, and software based on Motorola 6800 and 6809 microcomputer chips
• Sperry, which bought UNIVAC, and later merged with Burroughs to become Unisys
• Symbolics
• UNIVAC
• Varian Data Machines, a division of Varian Associates which was bought by Sperry
• Wang

Organizations

Professional

• Association for Computing Machinery (ACM)
• Association for Survey Computing (ASC)
• British Computer Society (BCS)
• Canadian Information Processing Society (CIPS)
• Computer Measurement Group (CMG)
• Institute of Electrical and Electronics Engineers (IEEE), in particular the IEEE Computer Society
• Institution of Electrical Engineers
• International Electrotechnical Commission (IEC)

Standards bodies

See also: Standardization and Standards organization

• International Electrotechnical Commission (IEC)
• International Organization for Standardization (ISO)
• Institute of Electrical and Electronics Engineers (IEEE)
• Internet Engineering Task Force (IETF)
• World Wide Web Consortium (W3C)

Open standards

See also Open standard

• Apdex Alliance -- Application Performance Index
• Application Response Measurement (ARM)

See also

Information technology portal

• Index of history of computing articles
• List of computer term etymologies

References

From Wikiquote

A computer is a machine for manipulating data according to a list of instructions. Computers take many forms, from early room-sized complexes to modern personal computers (PCs) and personal digital assistants (PDAs) to tiny embedded systems that add sophisticated capabilities to other devices like toys and appliances.

Sourced

• Dare to be gorgeous and unique. But don't ever be cryptic or otherwise unfathomable. Make it unforgettably great.
  • Robert J. Mical, Amiga Intuition Reference Manual, 1986, (ISBN 0201110768), p. 231

• Mr. McKitrick, after careful consideration I have come to the conclusion that your defense system sucks.
  • General Beringer (Barry Corbin) in WarGames, unidentified scene

• Trust The Computer. The Computer is your friend.
  • "Computer's Credo", Paranoia

• "So computers are tools of the devil?" thought Newt. He had no problem believing it. Computers had to be the tools of somebody, and all he knew for certain was that it definitely wasn't him.
  • Neil Gaiman and Terry Pratchett, Good Omens, chapter: Saturday, page 313 (Corgi Books, 1991, ISBN 0-552-13703-0)

• Never underestimate the bandwidth of a station wagon full of tapes hurtling down the highway.
  • Andrew S. Tanenbaum, Computer Networks 3rd Ed., 1996, Chapter 2 page 83

• The simple fact is that without supporting directives or a mechanism for feedback, security is defined differently by each person and verified by no one. There is no metric for compliance with a "culture", and a "culture of security" is overridden by a culture of "get the job done" every time. If there are rules, write them down. If technology is put in place to implement or monitor the rules, write that down too. If people break the rules, follow up. If the rules prevent legitimate business from getting done, change them. It's that simple.
  • Espenschied, Jon, "Ten claims that scare security pros", Computerworld, Infoworld.com, 14 August 2007. URL accessed on 2007-08-14.

• It used to be said of a man who had suffered a catastrophic setback in his line of work that he had been handed his head on a platter. We are being handed our heads with tweezers now.
  • Kurt Vonnegut, Timequake (1997), Ch. 9, p. 38. ISBN 0-425-16434-9

• I have bought this wonderful machine- a computer. Now I am rather an authority on gods, so I identified the machine- it seems to me to be an Old Testament god with a lot of rules and no mercy.
  • Joseph Campbell, The Power of Myth (1988), I, p.24 ISBN 0-385-41886-8

Software

• Around computers it is difficult to find the correct unit of time to measure progress. Some cathedrals took a century to complete. Can you imagine the grandeur and scope of a program that would take as long?
  • "Epigrams in Programming", SIGPLAN, Association for Computing Machinery, September 1982

• Einstein argued that there must be simplified explanations of nature, because God is not capricious or arbitrary. No such faith comforts the software engineer.
  • Fred Brooks, essay "No Silver Bullet", 1987

• A refund for defective software might be nice, except it would bankrupt the entire software industry in the first year.
  • Andrew S. Tanenbaum, Computer Networks, 2003, unidentified chapter/page

• Interviewer: Is studying computer science the best way to prepare to be a programmer? Bill Gates: No. the best way to prepare is to write programs, and to study great programs that other people have written. In my case, I went to the garbage cans at the Computer Science Center and I fished out listings of their operating system. You got to be willing to read other people's code, then write your own, then have other people review your code. You've got to want to be in this incredible feedback loop where you get the world-class people to tell you what you're doing wrong.
  • "Programmers at Work: Interviews With 19 Programmers Who Shaped the Computer Industry", Tempus, by Susan Lammers (Editor)

Computer games

• The only legitimate use of a computer is to play games.
  • Eugene Jarvis [1]

Programming

• The primary duty of an exception handler is to get the error out of the lap of the programmer and into the surprised face of the user.
  • Verity Stob. "Catch as catch can: A light-hearted look at exception handling", The Register, 11 January 2006. URL accessed on 2007-07-04.

Unix

• Your job is being a professor and researcher: That's one hell of a good excuse for some of the brain-damages of Minix.
  • Linus Torvalds to Tanenbaum (author of Minix) in the famous Usenet flame-war thread

• Will journalling become prevalent in the Unix world at large? Probably not. After all, it's nonstandard.
  • The UNIX Hater's Handbook, 1994, ISBN 1568842031, unidentified chapter/page

• Linux users think Abraham was ordered to sacrifice Linus as a burnt offering, GNU users think Abraham was ordered to sacrifice Stallman as a burnt offering. Linux users believe in the holy trinity of GNU/Linux/NvidiaBlobs, BSD users believe in the one and only UNIX. Linux users are fine with Tux toys and stickers, BSD users believe in no graven images. Linux users are subdivided into those that argue about interpretations of freedom and whether the establishment is corrupt, BSD users are subdivided according to which BSD is the true descendant of UNIX(pbuh).
  • kestasjk, Slashdot User - Slashdot Article

• UNIX is user-friendly, it just chooses its friends.
  • Andreas Bogk, Chaosradio 40

Unsourced

• If you think you can solve your security problems, then you don’t understand the problems and you don’t understand the technology.
  • Bruce Schneier

• The most likely way for the world to be destroyed, most experts agree, is by accident. That's where we come in; we're computer professionals. We cause accidents.
  • Nathaniel Borenstein

• Computer games don't affect kids, I mean if Pac Man affected us as kids, we'd all be running around in darkened rooms, munching pills and listening to repetitive music.
  • Marcus Brigstocke (falsely attributed to Kristian Wilson, Nintendo Inc)
  • See http://www.pacmanhattan.com/ though

• Quantum mechanic Seth Lloyd says the universe is one giant, hackable computer. Let's hope it's not running Windows.
  • Kevin Kelly

• On two occasions I have been asked [by members of parliament!], "Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?" I am not rightly able to apprehend the kind of confusion that could provoke such a question.
  • Charles Babbage

• Computers make it easier to do a lot of things, but most of the things they make it easier to do don't need to be done.
  • Andy Rooney

• The computer is the game.
  • Tom Christiansen

• Anyone who slaps a 'this page is best viewed with Browser X' label on a Web page appears to be yearning for the bad old days, before the Web, when you had very little chance of reading a document written on another computer, another word processor, or another network.
  • Tim Berners-Lee (in Technology Review, July 1996)

• [Software are among the] things which can be copied infinitely over and over again, without any further costs.
  • Eben Moglen, 2006

• A world full of computers which you can't understand, can't fix and can't use [because it is controlled by inaccessible proprietorial software] is a world controlled by machines.
  • Eben Moglen, 2006

• .HELP SEX: This system is a computer and as such is not able to help with enquiries of this nature. For details on reproduction, see the Xerox documentation.
  • Famous Help text from Essex Dec 10

• Computers in the future may weigh no more than 1.5 tons.
  • Popular Mechanics (1949)

• Computers are useless. They can only give you answers.
  • Pablo Picasso

• Don't trust a computer you can't throw out a window.
  • Steve Wozniak

• A computer is like air conditioning; it becomes useless when you open Windows.
  • Linus Torvalds

• "I'm not afraid of computers taking over the world. They're just sitting there. I can hit them with a two by four."
  • Thom Yorke

Misattributed

• I think there is a world market for maybe five computers.
  • Commonly attributed to Thomas J. Watson (1874–1956), general manager and chairman of IBM, but there is no evidence he ever said or wrote this. The earliest known citations occurred in the 1980s.[2]

See also

• Automation
• Machine
• Technology

External links

Wikipedia has an article about:

Computers

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The Computer Science Portal

Welcome to the Computer Science Portal. This Portal is a directory of Computer Science pages at Wikiversity. This directory page provides links to Computer Science learning resources that have been developed by the various Wikiversity Computer Science content development projects. The main content development project is the School of Computer Science. This portal features exciting examples of Computer Science learning resources. Wikiversity participants who are interested in Computer Science are invited to create and participate in learning projects and learning resources and help organize them by developing this portal. We're just starting, but we already have some good materials. The Computer Science Portal serves to provide quick access to everything in the Computer Science category.

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Building an artificial neural network using reinforcement learning strategies
This project is devoted to making a neural network model of hippocampal place cells and simulating the activity of model neurons under conditions that model when a laboratory animal is in a Morris water maze.

What is happening in an animal's brain as it learns to swim consistently straight to a target? At this point, science can't really answer this question in full detail. One can only speak of spatial learning, place learning, cognitive maps formation and memory in general. This project tries to explore a mathematical model of these processes by making use of computers.

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