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For the formal concept of computation, see computation.
Not to be confused with the magazine or the scientific journal.
"Computer technology" redirects here. For the company, see Computer Technology Limited.
A difference engine: computing the solution to a polynomial function
Computer laboratory, Moody Hall, James Madison University, 2003
A rack of servers from 2006

Computing is any goal-oriented activity requiring, benefiting from, or creating a mathematical sequence of steps known as an algorithm — e.g. through computers. Computing includes designing, developing and building hardware and software systems; processing, structuring, and managing various kinds of information; doing scientific research on and with computers; making computer systems behave intelligently; and creating and using communications and entertainment media. The field of computing includes computer engineering, software engineering, computer science, information systems, and information technology.


The ACM Computing Curricula 2005[1] defined "computing" as follows:

"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."

and it defines five sub-disciplines of the computing field: Computer Science, Computer Engineering, Information Systems, Information Technology, and Software Engineering.[2]

However, 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" has sometimes been narrowly defined, as in a 1989 ACM report on Computing as a Discipline:[3]

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?"

The term "computing" is also synonymous with counting and calculating. In earlier times, it was used in reference to the action performed by mechanical computing machines, and before that, to human computers.


1981 IBM 5150 computer.

The history of computing is longer than the history of computing hardware and modern computing technology and includes the history of methods intended for pen and paper or for chalk and slate, with or without the aid of tables.

Computing is intimately tied to the representation of numbers. But long before abstractions like the number arose, there were mathematical concepts to serve the purposes of civilization. These concepts include one-to-one correspondence (the basis of counting), comparison to a standard (used for measurement), and the 3-4-5 right triangle (a device for assuring a right angle).

The earliest known tool for use in computation was the abacus, and it was thought to have been invented in Babylon circa 2400 BC. Its original style of usage was by lines drawn in sand with pebbles. Abaci, of a more modern design, are still used as calculation tools today. This was the first known computer and most advanced system of calculation known to date - preceding Greek methods by 2,000 years.

The first recorded idea of using digital electronics for computing was the 1931 paper "The Use of Thyratrons for High Speed Automatic Counting of Physical Phenomena" by C. E. Wynn-Williams.[4] Claude Shannon's 1938 paper "A Symbolic Analysis of Relay and Switching Circuits" then introduced the idea of using electronics for Boolean algebraic operations.


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 a sequence of steps known as an 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 software and hardware[edit]

Main articles: Software and Computer hardware

Computer software or just "software", is a collection of computer programs and related data that provides the instructions for telling a computer what to do and how to do it. Software refers to one or more computer programs and data held in the storage of the computer for some purposes. In other words, software is a set of programs, procedures, algorithms and its documentation concerned with the operation of a data processing system. Program software performs the function of the program it implements, either by directly providing instructions to the computer hardware or by serving as input to another piece of software. The term was coined to contrast with the old term hardware (meaning physical devices). In contrast to hardware, software is intangible.[5] Software is also sometimes used in a more narrow sense, meaning application software only.

Application software[edit]

Main article: Application software

Application software, also known as an "application" or an "app", is a computer software designed to help the user to perform specific tasks. Examples include enterprise software, accounting software, office suites, graphics software and media players. Many application programs deal principally with documents. Apps may be bundled with the computer and its system software, or may be published separately. Some users are satisfied with the bundled apps and need never install one.

Application software is contrasted with system software and middleware, which manage and integrate a computer's capabilities, but typically do not directly apply them in the performance of tasks that benefit the user. The system software serves the application, which in turn serves the user.

Application software applies the power of a particular computing platform or system software to a particular purpose. Some apps such as Microsoft Office are available in versions for several different platforms; others have narrower requirements and are thus called, for example, a Geography application for Windows or an Android application for education or Linux gaming. Sometimes a new and popular application arises that only runs on one platform, increasing the desirability of that platform. This is called a killer application.

System software[edit]

Main article: System software

System software, or systems software, is computer software designed to operate and control the computer hardware and to provide a platform for running application software. System software includes operating systems, utility software, device drivers, window systems, and firmware. Frequently development tools such as compilers, linkers, and debuggers[6] are classified as system software.

Computer network[edit]

Main article: Computer network

A computer network, often simply referred to as a network, is a collection of hardware components and computers interconnected by communication channels that allow sharing of resources and information.[7] Where at least one process in one device is able to send/receive data to/from at least one process residing in a remote device, then the two devices are said to be in a network.

Networks may be classified according to a wide variety of characteristics such as the medium used to transport the data, communications protocol used, scale, topology, and organizational scope.

Communications protocols define the rules and data formats for exchanging information in a computer network, and provide the basis for network programming. Well-known communications protocols are Ethernet, a hardware and Link Layer standard that is ubiquitous in local area networks, and the Internet Protocol Suite, which defines a set of protocols for internetworking, i.e. for data communication between multiple networks, as well as host-to-host data transfer, and application-specific data transmission formats.

Computer networking is sometimes considered a sub-discipline of electrical engineering, telecommunications, computer science, information technology or computer engineering, since it relies upon the theoretical and practical application of these disciplines.


The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite (TCP/IP) to serve billions of users that consists of millions of private, public, academic, business, and government networks, of local to global scope, that are linked by a broad array of electronic, wireless and optical networking technologies. The Internet carries an extensive range of information resources and services, such as the inter-linked hypertext documents of the World Wide Web (WWW) and the infrastructure to support email.

Computer programming[edit]

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 behavior (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.

Computer programmer[edit]

A programmer, computer programmer, or coder is a person who writes computer software. The term computer programmer can refer to a specialist in one area of computer programming or to a generalist who writes code for many kinds of software. One who practices or professes a formal approach to programming may also be known as a programmer analyst. A programmer's primary computer language (C, C++, Java, Lisp, Python, etc.) is often prefixed to the above titles, and those who work in a web environment often prefix their titles with web. The term programmer can be used to refer to a software developer, software engineer, computer scientist, or software analyst. However, members of these professions typically[citation needed] possess other software engineering skills, beyond programming.

Computer industry[edit]

Main article: Computer industry

The computer industry is made up of all of the businesses involved in developing computer software, designing computer hardware and computer networking infrastructures, the manufacture of computer components and the provision of information technology services including system administration and maintenance.

Software industry[edit]

Main article: Software industry

The software industry includes businesses engaged in development, maintenance and publication of software. The industry also includes software services, such as training, documentation, and consulting.

Sub-disciplines of computing[edit]

Computer engineering[edit]

Main article: Computer engineering

Computer engineering is a discipline that integrates several fields of electrical engineering and computer science required to develop computer hardware and software.[8] Computer engineers usually have training in electronic engineering (or electrical engineering), software design, and hardware-software integration instead of only software engineering or electronic engineering. Computer engineers are involved in many hardware and software aspects of computing, from the design of individual microprocessors, personal computers, and supercomputers, to circuit design. This field of engineering not only focuses on how computer systems themselves work, but also how they integrate into the larger picture.[9]

Software engineering[edit]

Main article: Software engineering

Software engineering (SE) is the application of a systematic, disciplined, quantifiable approach to the design, development, operation, and maintenance of software, and the study of these approaches; that is, the application of engineering to software.[10][11][12] In layman's terms, it is the act of using insights to conceive, model and scale a solution to a problem. The first reference to the term is the 1968 NATO Software Engineering Conference and was meant to provoke thought regarding the perceived "software crisis" at the time.[13][14][15] Software development, a much used and more generic term, does not necessarily subsume the engineering paradigm. The generally accepted concepts of Software Engineering as an engineering discipline have been specified in the Guide to the Software Engineering Body of Knowledge (SWEBOK). The SWEBOK has become an internationally accepted standard ISO/IEC TR 19759:2005.[16]

Computer science[edit]

Computer science or computing science (abbreviated CS or Comp Sci) is the scientific and practical approach to computation and its applications. A computer scientist specializes in the theory of computation and the design of computational systems.[17]

Its subfields can be divided into practical techniques for its implementation and application in computer systems and purely theoretical areas. Some, such as computational complexity theory, which studies fundamental properties of computational problems, are highly abstract, while others, such as computer graphics, emphasize real-world applications. Still others focus on the challenges in implementing computations. For example, programming language theory studies approaches to description of computations, while the study of computer programming itself investigates various aspects of the use of programming languages and complex systems, and human–computer interaction focuses on the challenges in making computers and computations useful, usable, and universally accessible to humans.

Information systems[edit]

Main article: Information systems

"Information systems (IS)" is the study of complementary networks of hardware and software (see information technology) that people and organizations use to collect, filter, process, create, and distribute data.[18][19][20][21][22] Computing Careers says on their website that "A majority of IS programs are located in business schools; however, they may have different names such as management information systems, computer information systems, or business information systems. All IS degrees combine business and computing topics, but the emphasis between technical and organizational issues varies among programs. For example, programs differ substantially in the amount of programming required."[23] The study bridges business and computer science using the theoretical foundations of information and computation to study various business models and related algorithmic processes within a computer science discipline.[24][25][26][27][28][29][30][31][32][33] Computer Information System(s) (CIS) is a field studying computers and algorithmic processes, including their principles, their software and hardware designs, their applications, and their impact on society[34][35][36] while IS emphasizes functionality over design.[37]

Information technology[edit]

Information technology (IT) is the application of computers and telecommunications equipment to store, retrieve, transmit and manipulate data,[38] often in the context of a business or other enterprise.[39] The term is commonly used as a synonym for computers and computer networks, but it also encompasses other information distribution technologies such as television and telephones. Several industries are associated with information technology, such as computer hardware, software, electronics, semiconductors, internet, telecom equipment, e-commerce and computer services.[40][41]

Systems administration[edit]

Main article: System administrator

A system administrator, IT systems administrator, systems administrator, or sysadmin is a person employed to maintain and operate a computer system and/or network. The duties of a system administrator are wide-ranging, and vary widely from one organization to another. Sysadmins are usually charged with installing, supporting and maintaining servers or other computer systems, and planning for and responding to service outages and other problems. Other duties may include scripting or light programming, project management for systems-related projects, supervising or training computer operators, and being the consultant for computer problems beyond the knowledge of technical support staff.

Research and emerging technologies[edit]

DNA-based computing and quantum computing are areas of active research in both hardware and software (such the development of quantum algorithms). Potential infrastructure for future technologies includes DNA origami on photolithography[42] and quantum antennae for transferring information between ion traps.[43] By 2011, researchers had entangled 14 qubits.[44][45] Fast digital circuits (including those based on Josephson junctions and rapid single flux quantum technology) are becoming more nearly realizable with the discovery of nanoscale superconductors.[46]

Fiber-optic and photonic (optical) devices, which already have been used to transport data over long distances, have started being used by data centers, side by side with CPU and semiconductor memory components. This allows the separation of RAM from CPU by optical interconnects.[47] IBM has created an integrated circuit with both electronic and optical information processing in one chip. This is denoted "CMOS-integrated nanophotonics" or (CINP).[48] One benefit of optical interconnects is that motherboards which formerly required a certain kind of system on a chip (SoC) can now move formerly dedicated memory and network controllers off the motherboards, spreading the controllers out onto the rack. This allows standardization of backplane interconnects and motherboards for multiple types of SoCs, which allows more timely upgrades of CPUs.[49]

See also[edit]


  1. ^ a b The Joint Task Force for Computing Curricula 2005. "Computing Curricula 2005: The Overview Report" (pdf). 
  2. ^ "Curricula Recommendations". Association for Computing Machinery. 2005. Retrieved 2012-11-30. 
  3. ^ Peter J. Denning; et al. (January 1989). "Computing as a Discipline" (PDF). Communications of the ACM. Association for Computing Machinery. 32: 9–23. doi:10.1145/63238.63239. Retrieved 2012-11-30. 
  4. ^ Wynn-Williams, C. E. (July 2, 1931), "The Use of Thyratrons for High Speed Automatic Counting of Physical Phenomena", Proceedings of the Royal Society A, 132 (819): 295–310, Bibcode:1931RSPSA.132..295W, doi:10.1098/rspa.1931.0102 
  5. ^ " WordNet 2.0". Princeton University, Princeton, NJ. Retrieved 2007-08-19. 
  6. ^ Game of thrones. 
  7. ^ "Computer network definition". Retrieved 2011-11-12. 
  8. ^ IEEE Computer Society; ACM (12 December 2004). Computer Engineering 2004: Curriculum Guidelines for Undergraduate Degree Programs in Computer Engineering (pdf). p. iii. Retrieved 2012-12-17. Computer System engineering has traditionally been viewed as a combination ofboth electronic engineering (EE) and computer science (CS). 
  9. ^ Trinity College Dublin. "What is Computer System Engineering". Retrieved 2006-04-21. , "Computer engineers need not only to understand how computer systems themselves work, but also how they integrate into the larger picture. Consider the car. A modern car contains many separate computer systems for controlling such things as the engine timing, the brakes and the air bags. To be able to design and implement such a car, the computer engineer needs a broad theoretical understanding of all these various subsystems & how they interact.
  10. ^ Abran et al. 2004, pp. 1–1
  11. ^ ACM (2006). "Computing Degrees & Careers". ACM. Retrieved 2010-11-23. 
  12. ^ Laplante, Phillip (2007). What Every Engineer Should Know about Software Engineering. Boca Raton: CRC. ISBN 978-0-8493-7228-5. Retrieved 2011-01-21. 
  13. ^ Sommerville 2008, p. 26
  14. ^ Peter, Naur; Randell, Brian (7–11 October 1968). Software Engineering: Report of a conference sponsored by the NATO Science Committee (PDF). Garmisch, Germany: Scientific Affairs Division, NATO. Retrieved 2008-12-26. 
  15. ^ Randell, Brian (10 August 2001). "The 1968/69 NATO Software Engineering Reports". Brian Randell's University Homepage. The School of the Computer Sciences, Newcastle University. Retrieved 2008-10-11. The idea for the first NATO Software Engineering Conference, and in particular that of adopting the then practically unknown term "software engineering" as its (deliberately provocative) title, I believe came originally from Professor Fritz Bauer. 
  16. ^ "ISO/IEC TR 19759:2005". Retrieved 2012-04-01. 
  17. ^ "WordNet Search - 3.1". Retrieved 2012-05-14. 
  18. ^ "Definition of Application Landscape". Software Engineering for Business Information Systems (sebis). Jan 21, 2009. Retrieved January 14, 2011. 
  19. ^ Archibald, J.A. (May 1975). "Computer Science education for majors of other disciplines". AFIPS Joint Computer Conferences: 903–906. Computer science spreads out over several related disciplines, and shares with these disciplines certain sub-disciplines that traditionally have been located exclusively in the more conventional disciplines 
  20. ^ Denning, Peter (July 1999). "COMPUTER SCIENCE: THE DISCIPLINE". Encyclopaedia of Computer Science (2000 Edition). The Domain of Computer Science: Even though computer science addresses both human-made and natural information processes, the main effort in the discipline has been directed toward human-made processes, especially information processing systems and machines 
  21. ^ Coy, Wolfgang (June 2004). "Between the disciplines". ACM SIGCSE Bulletin. 36 (2): 7–10. doi:10.1145/1024338.1024340. ISSN 0097-8418. Computer science may be in the core of these processes. The actual question is not to ignore disciplinary boundaries with its methodological differences but to open the disciplines for collaborative work. We must learn to build bridges, not to start in the gap between disciplines 
  22. ^ Jessup, Leonard M.; Valacich, Joseph S. (2008). Information Systems Today (3rd ed.). Pearson Publishing. pp. ???, 416. 
  23. ^ "Computing Degrees and Careers, Association for Computing Machinery". 
  24. ^ Hoganson, Ken (December 2001). "Alternative curriculum models for integrating computer science and information systems analysis, recommendations, pitfalls, opportunities, accreditations, and trends". Journal of Computing Sciences in Colleges. 17 (2): 313–325. ISSN 1937-4771. ... Information Systems grew out of the need to bridge the gap between business management and computer science ... 
  25. ^ Davis, Timothy; Geist, Robert; Matzko, Sarah; Westall, James (March 2004). "τ´εχνη: A First Step". Technical Symposium on Computer Science Education: 125–129. ISBN 1-58113-798-2. In 1999, Clemson University established a (graduate) degree program that bridges the arts and the sciences... All students in the program are required to complete graduate level work in both the arts and computer science 
  26. ^ Hoganson, Ken (December 2001). "Alternative curriculum models for integrating computer science and information systems analysis, recommendations, pitfalls, opportunities, accreditations, and trends". Journal of Computing Sciences in Colleges. 17 (2): 313–325. ISSN 1937-4771. The field of information systems as a separate discipline is relatively new and is undergoing continuous change as technology evolves and the field matures 
  27. ^ Khazanchi, Deepak; Bjorn Erik Munkvold (Summer 2000). "Is information system a science? an inquiry into the nature of the information systems discipline". ACM SIGMIS Database. 31 (3): 24–42. doi:10.1145/381823.381834. ISSN 0095-0033. From this we have concluded that IS is a science, i.e., a scientific discipline in contrast to purportedly non-scientific fields 
  28. ^ Denning, Peter (June 2007). "Ubiquity a new interview with Peter Denning on the great principles of computing". 2007 (June): 1–1. People from other fields are saying they have discovered information processes in their deepest structures and that collaboration with computing is essential to them. 
  29. ^ "Computer science is the study of information". New Jersey Institute of Technology: Gutenberg Information Technologies. Archived from the original on May 29, 2009. 
  30. ^ Computer Science Department, College of Saint Benedict. "Computer science is the study of computation". Saint John's University. 
  31. ^ "Computer Science is the study of all aspects of computer systems, from the theoretical foundations to the very practical aspects of managing large software projects". Massey University. 
  32. ^ Kelly, Sue; Gibson, Nicola; Holland, Christopher; Light, Ben (July 1999). "Focus Issue on Legacy Information Systems and Business Process Engineering: a Business Perspective of Legacy Information Systems". Communications of the AIS. 2 (7): 1–27. 
  33. ^ Pearson Custom Publishing & West Chester University (2009). Custom Program for Computer Information Systems (CSC 110). Pearson Custom Publishing. p. 694. 
  34. ^ Polack, Jennifer (December 2009). "Planning a CIS Education Within a CS Framework". Journal of Computing Sciences in Colleges. 25 (2): 100–106. ISSN 1937-4771. 
  35. ^ Hayes, Helen; Onkar Sharma (February 2003). "A decade of experience with a common first year program for computer science, information systems and information technology majors". Journal of Computing Sciences in Colleges. 18 (3): 217–227. ISSN 1937-4771. In 1988, a degree program in Computer Information Systems (CIS) was launched with the objective of providing an option for students who were less inclined to become programmers and were more interested in learning to design, develop, and implement Information Systems, and solve business problems using the systems approach 
  36. ^ CSTA Committee; Allen Tucker; et alia (2006). A Model Curriculum for K-12 Computer Science (Final Report). Association for Computing Machinery, Inc. pp. 0, 2. 
  37. ^ Freeman, Peter; Hart, David (August 2004). "A Science of Design for Software-Intensive Systems Computer science and engineering needs an intellectually rigorous, analytical, teachable design process to ensure development of systems we all can live with". Communications of the ACM. 47 (8): 19–21. doi:10.1145/1012037.1012054. ISSN 0001-0782. Though the other components' connections to the software and their role in the overall design of the system are critical, the core consideration for a software-intensive system is the software itself, and other approaches to systematizing design have yet to solve the "software problem"—which won't be solved until software design is understood scientifically 
  38. ^ Daintith, John, ed. (2009), "IT", A Dictionary of Physics, Oxford University Press, retrieved 1 August 2012  (subscription required)
  39. ^ "Free on-line dictionary of computing (FOLDOC)". Retrieved 9 Feb 2013. 
  40. ^ Chandler, Daniel; Munday, Rod, "Information technology", A Dictionary of Media and Communication (first ed.), Oxford University Press, retrieved 1 August 2012  (subscription required)
  41. ^ On the later more broad application of the term IT, Keary comments- "In its original application 'information technology' was appropriate to describe the convergence of technologies with application in the broad field of data storage, retrieval, processing, and dissemination. This useful conceptual term has since been converted to what purports to be concrete use, but without the reinforcement of definition...the term IT lacks substance when applied to the name of any function, discipline, or position." Anthony Ralston (2000). Encyclopedia of computer science. Nature Pub. Group. ISBN 978-1-56159-248-7. Retrieved 12 May 2013. .
  42. ^ Ryan J. Kershner, Luisa D. Bozano, Christine M. Micheel, Albert M. Hung, Ann R. Fornof, Jennifer N. Cha, Charles T. Rettner, Marco Bersani, Jane Frommer, Paul W. K. Rothemund & Gregory M. Wallraff (16 August 2009) "Placement and orientation of individual DNA shapes on lithographically patterned surfaces" Nature Nanotechnology publication information, supplementary information: DNA origami on photolithography doi:10.1038/nnano.2009.220
  43. ^ M. Harlander, R. Lechner, M. Brownnutt, R. Blatt, W. Hänsel. Trapped-ion antennae for the transmission of quantum information. Nature, 2011; doi:10.1038/nature09800
  44. ^ Thomas Monz, Philipp Schindler, Julio T. Barreiro, Michael Chwalla, Daniel Nigg, William A. Coish, Maximilian Harlander, Wolfgang Hänse, Markus Hennrich, and Rainer Blatt, (31 March 2011) "14-Qubit Entanglement: Creation and Coherence" Phys. Rev. Lett. 106 13 doi:10.1103/PhysRevLett.106.130506
  45. ^ "World record: Calculations with 14 quantum bits". 
  46. ^ Saw-Wai Hla et al., Nature Nanotechnology March 31, 2010 "World’s smallest superconductor discovered". Four pairs of certain molecules have been shown to form a nanoscale superconductor, at a dimension of 0.87 nanometers. Access date 2010-03-31
  47. ^ Tom Simonite, "Computing at the speed of light", Technology Review Wed., August 4, 2010 MIT
  48. ^ Sebastian Anthony (Dec 10,2012), "IBM creates first commercially viable silicon nanophotonic chip", accessdate=2012-12-10
  49. ^ Open Compute: Does the data center have an open future? accessdate=2013-08-11


External links[edit]