Computer

A computer is a device or for processing information from data according to a program — a compiled list of instructions. The information to be processed may represent numbers, text, pictures, or sound, amongst many other types.

History

Originally, a "computer" was a person who performed numerical calculations under the direction of a mathematician, often with the aid of a variety of mechanical calculating devices from the abacus onward. An example of an early computing device was the Antikythera mechanism, an ancient Greek device for calculating the movements of planets, dating from about 87 BC. The technology responsible for this mysterious device seems to have been lost at some point.

Related Topics:
Mathematician - Mechanical calculating device - Abacus - Antikythera mechanism - 87 BC

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With the reinvigoration of European mathematics and engineering in the end of the Middle Ages, a succession of mechanical calculating devices were constructed based on technology developed for clockwork by the early 17th century. A considerable number of technologies that would later prove vital for the digital computer were developed in the 19th and early 20th centuries, such as the punched card, and the valve. In the 19th century, Charles Babbage was the first to conceptualise and design a fully programmable computer as early as 1837, but due to a combination of the limits of the technology of the time, limited finance, and an inability to resist tinkering with his design (a trait that would in time doom thousands of computer-related engineering projects) ensured that the device was never actually constructed in his time.

Related Topics:
Clockwork - Punched card - Valve - Charles Babbage

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During the first half of the 20th century, many scientific computing needs were met by some increasingly sophisticated, special purpose analog computers, which used a direct physical or electrical model of the problem as a basis for computation. These became increasingly rare after the development of the digital computer.

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The Colossus computer was used to break German ciphers during World War II

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A succession of steadily more powerful and flexible computing devices were constructed in the 1930's and 1940's, gradually adding the key features of modern computers: the use of digital electronics (essentially invented by Claude Shannon in 1937), and more flexible programmability. Defining one point along this road as "the first computer" is exceedingly difficult. Notable achievements include the Atanasoff Berry Computer, a special-purpose machine that used valve-driven computation and binary numbers; Konrad Zuse's Z machines; the electro-mechanical Z3 was arguably the first universal computer, but it was completely impractical to use in this manner; the American ENIAC - a general purpose machine, but with an inflexible architecture that meant reprogramming it essentially required it to be rewired; and the secret British Colossus computer, which had limited programmability but demonstrated that a device using thousands of valves could be made reliable and reprogrammed electronically.

Related Topics:
Claude Shannon - Atanasoff Berry Computer - Konrad Zuse - ENIAC - Colossus computer

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The team who developed ENIAC, recognizing its flaws, came up with a far more flexible and elegant design which has become known as the stored program architecture, which is the basis from which virtually all modern computers were derived. A number of projects to develop computers based on the ENIAC architecture commenced in the late 1940's; the first of these to be up and running was the Manchester Small-Scale Experimental Machine, but the EDSAC was perhaps the first practical version.

Related Topics:
Stored program architecture - Small-Scale Experimental Machine - EDSAC

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Valve-driven computers design were used throughout the 1950's, but were eventually replaced with transistor-based computers in the 1960's, which were smaller, faster, cheaper, and much more reliable, and thus smaller, faster, and cheaper computers became available commercially. By the 1970's, the adoption of integrated circuit technology had enabled computers to be produced at a low enough cost to allow individuals to own a personal computer of the type familiar today.

Related Topics:
Transistor - Integrated circuit - Personal computer

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