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Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of
algorithm of an algorithm (Euclid's algorithm) for calculating the greatest common divisor (g.c.d.) of two numbers ''a'' and ''b'' in locations named A and B. The algorithm proceeds by successive subtractions in two loops: IF the test B ≥ A yields "yes" ...

algorithm
ic processes and development of both hardware and
software Software is a collection of instructions that tell a computer A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations automatically. Modern computers can perform generic sets of operatio ...

software
. It has scientific, engineering, mathematical, technological and social aspects. Major computing disciplines include
computer engineering Computer engineering (CoE or CpE) is a branch of engineering Engineering is the use of scientific method, scientific principles to design and build machines, structures, and other items, including bridges, tunnels, roads, vehicles, and ...
,
computer science Computer science deals with the theoretical foundations of information, algorithms and the architectures of its computation as well as practical techniques for their application. Computer science is the study of Algorithm, algorithmic proc ...
,
cybersecurity
cybersecurity
,
data science Data science is an Interdisciplinarity, interdisciplinary field that uses scientific methods, processes, algorithms and systems to extract knowledge and insights from structured and unstructured data, and apply knowledge and actionable insights ...
,
information systems An information system (IS) is a formal, sociotechnical, organizational system designed to collect, process, store, and distribute information. In a sociotechnical perspective, information systems are composed by four components: task, people, struc ...
, information technology and
software engineering Software engineering is the systematic application of engineering approaches to the software development, development of software. A software engineer is a person who applies the principles of software engineering to design, develop, maintain, tes ...
. The term "computing" is also
synonymous A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in the same language. For example, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all synonyms of one another ...
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 computer NACA High Speed Flight Station "Computer Room" (1949) The term "computer", in use from the early 17th century (the first known written reference dates from 1613), meant "one who computes": a person performing mathematical calculations, before e ...
s.


History

The history of computing is longer than the
history of computing hardware The history of computing hardware covers the developments from early simple devices to aid calculation to modern day computers. Before the 20th century, most calculations were done by humans. Early mechanical tools to help humans with digital c ...
and
modern computing technology
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
number A number is a mathematical object A mathematical object is an abstract concept arising in mathematics. In the usual language of mathematics, an ''object'' is anything that has been (or could be) formally defined, and with which one may do deduct ...

number
s. But long before
abstraction Abstraction in its main sense is a conceptual process where general rules and concept Concepts are defined as abstract ideas or general notions that occur in the mind, in speech, or in thought. They are understood to be the fundamental buildin ...

abstraction
s like ''the number'' arose, there were mathematical concepts to serve the purposes of civilization. These concepts include
one-to-one correspondence In mathematics Mathematics (from Ancient Greek, Greek: ) includes the study of such topics as quantity (number theory), mathematical structure, structure (algebra), space (geometry), and calculus, change (mathematical analysis, analysis). It ...
(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 The abacus (''plural'' abaci or abacuses), also called a counting frame, is a calculating tool that has been in use since ancient times and is still in use today. It was used in the ancient Near East, Europe, China, and Russia, centuries befo ...
, and it was thought to have been invented in
Babylon ''Bābili(m)'' * sux, 𒆍𒀭𒊏𒆠 * arc, 𐡁𐡁𐡋 ''Babil'' * grc-gre, Βαβυλών ''Babylṓn'' * he, בָּבֶל ''Bavel'' * peo, 𐎲𐎠𐎲𐎡𐎽𐎢 ''Bābiru'' * elx, 𒀸𒁀𒉿𒇷 ''Babili'' * Kassite: ''Karanduniash'' ...
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 calculation aid – 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.
Claude Shannon Claude Elwood Shannon (April 30, 1916 – February 24, 2001) was an American mathematician A mathematician is someone who uses an extensive knowledge of mathematics Mathematics (from Ancient Greek, Greek: ) includes the study of such top ...
's 1938 paper " A Symbolic Analysis of Relay and Switching Circuits" then introduced the idea of using electronics for
Boolean algebra In mathematics Mathematics (from Ancient Greek, Greek: ) includes the study of such topics as quantity (number theory), mathematical structure, structure (algebra), space (geometry), and calculus, change (mathematical analysis, analysis). It ...
ic operations. The concept of a
field-effect transistor The field-effect transistor (FET) is a type of transistor that uses an electric field to control the flow of Electric current, current in a semiconductor. FETs are devices with three terminals: ''source'', ''gate'', and ''drain''. FETs control t ...
was proposed by
Julius Edgar Lilienfeld Julius Edgar Lilienfeld (April 18, 1882 – August 28, 1963) was an Austro-Hungarian, and later American (where he moved in 1921) physicist and electrical engineer, who was credited with the first patent on the field-effect transistor The f ...
in 1925.
John Bardeen John Bardeen (; May 23, 1908 – January 30, 1991) was an American physicist A physicist is a scientist A scientist is a person who conducts Scientific method, scientific research to advance knowledge in an Branches of science, area of inte ...
and
Walter Brattain Walter Houser Brattain (; February 10, 1902 – October 13, 1987) was an American physicist at Bell Labs Nokia Bell Labs (formerly named Bell Labs Innovations (1996–2007), AT&T Bell Laboratories (1984–1996) and Bell Telephone Laboratories ...
, while working under
William Shockley William Bradford Shockley Jr. (February 13, 1910 – August 12, 1989) was an American physicist and inventor. He was the manager of a research group at Bell Labs Nokia Bell Labs (formerly named Bell Labs Innovations (1996–2007), AT&T Bell L ...
at
Bell Labs Nokia Bell Labs (formerly named Bell Labs Innovations (1996–2007), AT&T Bell Laboratories (1984–1996) and Bell Telephone Laboratories (1925–1984)) is an American industrial Research and development, research and scientific development S.A. ...
, built the first working
transistor file:MOSFET Structure.png, upright=1.4, Metal-oxide-semiconductor field-effect transistor (MOSFET), showing Metal gate, gate (G), body (B), source (S) and drain (D) terminals. The gate is separated from the body by an insulating layer (pink). A ...

transistor
, the
point-contact transistor The point-contact transistor was the first type of transistor to be successfully demonstrated. It was developed by research scientists John Bardeen and Walter Brattain at Bell Laboratories in December 1947. They worked in a group led by physici ...

point-contact transistor
, in 1947. In 1953, the
University of Manchester , mottoeng = Knowledge, Wisdom, Humanity , established = 2004 – University of Manchester Predecessor institutions: 1956 – UMIST (as university college; university 1994) 1904 – Victoria University of Manchester 1880 – Victoria Univer ...

University of Manchester
built the first
transistorized computer A transistor computer, now often called a second generation computer, is a computer which uses discrete transistors instead of vacuum tubes. The first generation of electronic computers used vacuum tubes, which generated large amounts of heat, w ...
, called the
Transistor Computer A transistor computer, now often called a second generation computer, is a computer A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations automatically. Modern computers can perform gene ...
. However, early junction transistors were relatively bulky devices that were difficult to manufacture on a mass-production basis, which limited them to a number of specialised applications. The
metal–oxide–silicon field-effect transistor
metal–oxide–silicon field-effect transistor
(MOSFET, or MOS transistor) was invented by
Mohamed Atalla Mohamed M. Atalla ( ar, محمد عطاالله; August 4, 1924 – December 30, 2009) was an Egyptian Americans, Egyptian-American engineer, Physical chemistry, physical chemist, cryptographer, inventor and entrepreneur. He was a semiconducto ...
and
Dawon Kahng Dawon Kahng ( ko, 강대원; May 4, 1931 – May 13, 1992) was a Korean-American electrical engineer and inventor, known for his work in solid-state electronics. He is best known for inventing the MOSFET (metal–oxide–semiconductor field-effect ...

Dawon Kahng
at Bell Labs in 1959. It was the first truly compact transistor that could be miniaturised and
mass-produced Mass production, also known as flow production or continuous production, is the production of substantial amounts of standardized Standardization or standardisation is the process of implementing and developing technical standard A technic ...
for a wide range of uses. The MOSFET made it possible to build high-density
integrated circuit An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on one small flat piece (or "chip") of semiconductor material, usually silicon. Transistor count, Larg ...

integrated circuit
chips, leading to what is known as the computer revolution or
microcomputer revolution The history of the personal computer as a mass-market consumer electronic device began with the microcomputer revolution of the 1970s. A personal computer is one intended for interactive individual use, as opposed to a mainframe computer where t ...
.


Computer

A computer is a machine that manipulates
data Data (; ) are individual facts, statistics, or items of information, often numeric. In a more technical sense, data are a set of values of qualitative property, qualitative or quantity, quantitative variable (research), variables about one or m ...
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 CPU type. The execution
process A process is a series or set of Action (philosophy), activities that interact to produce a result; it may occur once-only or be recurrent or periodic. Things called a process include: Business and management *Business process, activities that pro ...
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 Semantics (from grc, σημαντικός ''sēmantikós'', "significant") is the study of reference Reference is a relationship between objects in which one object designates, or acts as a means by which to connect to or link to, another o ...
of the instructions.


Computer hardware

Computer hardware includes the physical parts of a computer, including
central processing unit A central processing unit (CPU), also called a central processor, main processor or just Processor (computing), processor, is the electronic circuitry that executes Instruction (computing), instructions comprising a computer program. The CPU per ...
,
memory Memory is the faculty of the brain A brain is an organ (biology), organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for sense ...

memory
and
input/output In computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes and development of both computer hardware , hardware and softwa ...
. Important topics in the field of computer hardware are
computational logic Computational logic is the use of logic to perform or reason about computation. It bears a similar relationship to computer science and engineering as mathematical logic bears to mathematics and as philosophical logic bears to philosophy. It is sy ...
and
computer architecture In computer engineering Computer engineering (CoE or CpE) is a branch of engineering Engineering is the use of scientific method, scientific principles to design and build machines, structures, and other items, including bridges, tunn ...
.


Computer software

Computer software, or just "software", is a collection of computer programs and related
data Data (; ) are individual facts, statistics, or items of information, often numeric. In a more technical sense, data are a set of values of qualitative property, qualitative or quantity, quantitative variable (research), variables about one or m ...
that provides the instructions for telling a
computer A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations automatically. Modern computers can perform generic sets of operations known as Computer program, programs. These programs enable compu ...

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 Function or functionality may refer to: Computing * Function key A function key is a key on a computer A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations automatically. Modern comp ...
of the program it implements, either by directly providing
instructions Instruction or instructions may refer to: Computing * Instruction, one operation of a processor within a computer architecture instruction set * Computer program, a collection of instructions Music * Instruction (band), a 2002 rock band from New Y ...
to the computer hardware or by serving as input to another piece of software. The was coined to contrast with the old term ''
hardware Hardware may refer to: Technology Computing and electronics * Computer hardware, physical parts of a computer * Digital electronics, electronics that operate on digital signals * Electronic component, device in an electronic system used to affect e ...
'' (meaning physical devices). In contrast to hardware, software is intangible. Software is also sometimes used in a more narrow sense, meaning application software only.


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 system An operating system (OS) is system software that manages computer hardware, computer software, software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), sch ...

operating system
s,
utility software Utility software is software designed to help to analyze, configure, optimize or maintain a computer. It is used to support the computer infrastructure Infrastructure is the set of fundamental facilities and systems that support the sustainable fun ...
,
device driver In computing, a device driver is a computer program that operates or controls a particular type of Peripheral, device that is attached to a computer or automaton. A driver provides a software Interface (computing), interface to Computer hardware, ...
s, window systems, and
firmware In computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes and development of both computer hardware , hardware and softwa ...
. Frequently used development tools such as
compiler In computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes and development of both computer hardware , hardware and soft ...

compiler
s,
linker Linker or linkers may refer to: Computing * Linker (computing) In computing, a linker or link editor is a computer System software, system program that takes one or more object files (generated by a compiler or an assembler (computing), asse ...
s, and
debuggers A debugger or debugging tool is a computer program used to software testing, test and debugging, debug other programs (the "target" program). The main use of a debugger is to run the target program under controlled conditions that permit the pro ...
are classified as system software.


Application software

Application software, also known as an "application" or an "app", is
computer software Software is a collection of Instruction (computer science), instructions that tell a computer how to work. This is in contrast to Computer hardware, hardware, from which the system is built and actually performs the work. At the low level langu ...
designed to help the user to perform specific tasks. Examples include
enterprise softwareEnterprise software, also known as enterprise application software (EAS), is computer software Software is a collection of Instruction (computer science), instructions and data (computing), data that tell a computer how to work. This is in contr ...
,
accounting software Accounting software describes a type of application software Application software (app for short) is computing software designed to carry out a specific task other than one relating to the operation of the computer itself, typically to be used ...
,
office suite Productivity software (also called personal productivity software or office productivity software) is application software used for producing information (such as documents, presentations, worksheets, databases, charts, Information graphics, graphs, ...
s,
graphics software In computer graphics, graphics software refers to a program or collection of programs that enable a person to manipulate images or models visually on a computer A computer is a machine that can be programmed to carry out sequences of arith ...
and media players. Many application programs deal principally with
documents A document is a writing, written, drawing, drawn, presented, or memorialized representation of thought, often the manifestation of nonfiction, non-fictional, as well as fictional, content. The word originates from the Latin ''Documentum'', which ...
. 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 additional applications. Application software is contrasted with
system software System software is software designed to provide a platform for other software. Examples of system software include operating systems like macOS macOS (; previously Mac OS X and later OS X) is a Proprietary software, proprieta ...
and
middleware Middleware is a computer software Software is a collection of Instruction (computer science), instructions and data (computing), data that tell a computer how to work. This is in contrast to Computer hardware, physical hardware, from which the ...

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 A computing platform or digital platform is the environment in which a piece of software Software is a collection of Instruction (computer science), instructions and data (computing), data that tell a computer how to work. This is in contrast ...
or system software to a particular purpose. Some apps such as
Microsoft Office Microsoft Office, or simply Office, is a family of client software In computing, a client is a piece of computer hardware or software that accesses a service made available by a Server (computing), server as part of the client–server mod ...
are available in versions for several different platforms; others have narrower requirements and are thus called, for example, a
Geography Geography (from Greek: , ''geographia'', literally "earth description") is a field of science devoted to the study of the lands, features, inhabitants, and phenomena of the Earth and planets. The first person to use the word γεωγρα ...
application for
Windows Microsoft Windows, commonly referred to as Windows, is a group of several proprietary {{Short pages monitor