Computing

For the formal concept of computation, see computation. For the magazine, see Computing (magazine). For the scientific journal, see Computing (journal).

A difference engine: computing the solution to a polynomial function

Computer laboratory, Moody Hall, James Madison University, 2003

Wikimedia servers

Computing is usually defined as the activity of using and improving 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" as:

"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 often more restrictive or demanding than natural languages, 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" 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 a machine that reads, stores, manipulates and displays data. The most common example are the various personal computers. Other common examples include: mobile phones, mp3 players, or video game consoles.

Science and theory

The 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. Common topics include:

Computer science Theory of computation Computational models Scientific computing

Metacomputing Topological computing Autonomic Computing

Hardware

See information processor for a high-level block diagram.

Computer Computer Hardware Design Computer network

Computer system History of computing hardware

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 assemblers Speech recognition Speech synthesis

Part of an early computer, EDSAC.

History of computing

History of computing hardware from the tally stick to the quantum computer History of computer science Punched card Unit record equipment

IBM 700/7000 series IBM 1400 series System/360 Early IBM disk storage

Business computing

Accounting software Computer-aided design Computer-aided manufacturing Computer-assisted dispatch Customer relationship management Data warehouse Decision support system Electronic data processing

Enterprise resource planning Geographic information system Management information system Material requirements planning Strategic enterprise management Supply chain management Product Lifecycle Management Utility Computing

Human factors

Accessible computing Computer-induced medical problems Computer user satisfaction

Human-computer interaction Human-centered computing

Computer network

Wired and wireless computer network

This notebook computer is connected to a wireless access point using a PC card wireless card.

• 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 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

• Cryptology – cryptography – information theory
• Cracking – demon dialing – Hacking – war dialing – war driving
• Social engineering – Dumpster diving
• Physical security – Black bag job
• Computer insecurity
• Computer surveillance
• Defensive programming
• Malware
• Security engineering

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 Index (computer science)

Data management Routing Data Protection Act

Classes of computers

Polish analog computer AKAT-1

There are several terms which describe classes, or categories, of computers:

Analog computer Calculator Desktop computer Desktop replacement computer Digital computer Embedded computer Home computer Laptop Mainframe Minicomputer Microcomputer

Personal computer Portable computer Personal digital assistant (aka PDA, or Handheld computer) Programmable logic controller or PLC Server Supercomputer Tablet computer Tablet PC Video game console Workstation

Companies – current

Apple Asus Avaya Dell Fujitsu Gateway Computers Groupe Bull HCL Hewlett-Packard Hitachi, Ltd. Intel Corporation

IBM Lenovo Microsoft NEC Corporation Novell Panasonic Red Hat Silicon Graphics Sun Microsystems Unisys

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, later 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 Norsk Data Olivetti Osborne Packard Bell PERQ 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

A computer Lab

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
	Computer Science portal
	Computing portal

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

References

1. ^ ^{a b} The Joint Task Force for Computing Curricula 2005. Computing Curricula 2005: The Overview Report (pdf)
2. ^ Computing as a Discipline (pdf)

External links

http://foldoc.org/contents.html Free on-line dictionary of computing

http://pubs.doc.ic.ac.uk/ open-access repository of publications - Department of Computing - Imperial College London