Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery.[1] It includes the study and experimentation of algorithmic processes, and development of both hardware and software. Computing has scientific, engineering, mathematical, technological, and social aspects. Major computing disciplines include computer engineering, computer science, cybersecurity, data science, information systems, information technology, and software engineering.[2]
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.[3]
The history of computing is longer than the history of computing hardware 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, though mathematical concepts necessary for computing existed before numeral systems. The earliest known tool for use in computation is the abacus, and it is thought to have been invented in Babylon circa between 2700–2300 BC. Abaci, of a more modern design, are still used as calculation tools today.
The first recorded proposal for using digital electronics in 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.
The concept of a field-effect transistor was proposed by Julius Edgar Lilienfeld in 1925. John Bardeen and Walter Brattain, while working under William Shockley at Bell Labs, built the first working transistor, the point-contact transistor, in 1947.[5][6] In 1953, the University of Manchester built the first transistorized computer, the Manchester Baby.[7] However, early junction transistors were relatively bulky devices that were difficult to mass-produce, which limited them to a number of specialised applications.[8] The metal–oxide–silicon field-effect transistor (MOSFET, or MOS transistor) was invented by Mohamed Atalla and Dawon Kahng at Bell Labs in 1959.[9][10] The MOSFET made it possible to build high-density integrated circuits,[11][12] leading to what is known as the computer revolution[13] or microcomputer revolution.[14]
A computer is a machine that manipulates data according to a set of instructions called a computer program.[15] 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.[16] 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.[17]