Please forward this error screen to 81. A computer is a device that can be instructed to carry out sequences of arithmetic or logical computer monitor repair automatically. Modern computers have the ability to follow generalized sets of operations, called programs.

Computers are used as control systems for a wide variety of industrial and consumer devices. Early computers were only conceived as calculating devices. Since ancient times, simple manual devices like the abacus aided people in doing calculations. Early in the Industrial Revolution, some mechanical devices were built to automate long tedious tasks, such as guiding patterns for looms.

According to the Oxford English Dictionary, the first known use of the word “computer” was in 1613 in a book called The Yong Mans Gleanings by English writer Richard Braithwait: “I haue read the truest computer of Times, and the best Arithmetician that euer breathed, and he reduceth thy dayes into a short number. This usage of the term referred to a person who carried out calculations or computations. Devices have been used to aid computation for thousands of years, mostly using one-to-one correspondence with fingers. The earliest counting device was probably a form of tally stick. The abacus was initially used for arithmetic tasks. The Roman abacus was developed from devices used in Babylonia as early as 2400 BC.

Since then, many other forms of reckoning boards or tables have been invented. The ancient Greek-designed Antikythera mechanism, dating between 150 and 100 BC, is the world’s oldest analog computer. The Antikythera mechanism is believed to be the earliest mechanical analog “computer”, according to Derek J. It was designed to calculate astronomical positions. Many mechanical aids to calculation and measurement were constructed for astronomical and navigation use. The planisphere was a star chart invented by Abū Rayhān al-Bīrūnī in the early 11th century. The sector, a calculating instrument used for solving problems in proportion, trigonometry, multiplication and division, and for various functions, such as squares and cube roots, was developed in the late 16th century and found application in gunnery, surveying and navigation.

The planimeter was a manual instrument to calculate the area of a closed figure by tracing over it with a mechanical linkage. 1630, shortly after the publication of the concept of the logarithm. It is a hand-operated analog computer for doing multiplication and division. By switching the number and order of its internal wheels different letters, and hence different messages, could be produced. The tide-predicting machine invented by Sir William Thomson in 1872 was of great utility to navigation in shallow waters. It used a system of pulleys and wires to automatically calculate predicted tide levels for a set period at a particular location. The differential analyser, a mechanical analog computer designed to solve differential equations by integration, used wheel-and-disc mechanisms to perform the integration.

A portion of Babbage’s Difference engine. Charles Babbage, an English mechanical engineer and polymath, originated the concept of a programmable computer. The machine was about a century ahead of its time. Eventually, the project was dissolved with the decision of the British Government to cease funding. During the first half of the 20th century, many scientific computing needs were met by increasingly sophisticated analog computers, which used a direct mechanical or electrical model of the problem as a basis for computation. The art of mechanical analog computing reached its zenith with the differential analyzer, built by H. Hazen and Vannevar Bush at MIT starting in 1927.

It has been suggested that this section be split out into another article titled Digital computer. By 1938, the United States Navy had developed an electromechanical analog computer small enough to use aboard a submarine. This was the Torpedo Data Computer, which used trigonometry to solve the problem of firing a torpedo at a moving target. These devices had a low operating speed and were eventually superseded by much faster all-electric computers, originally using vacuum tubes. In 1941, Zuse followed his earlier machine up with the Z3, the world’s first working electromechanical programmable, fully automatic digital computer.

Purely electronic circuit elements soon replaced their mechanical and electromechanical equivalents, at the same time that digital calculation replaced analog. Colossus was the first electronic digital programmable computing device, and was used to break German ciphers during World War II. During World War II, the British at Bletchley Park achieved a number of successes at breaking encrypted German military communications. The German encryption machine, Enigma, was first attacked with the help of the electro-mechanical bombes. Colossus was the world’s first electronic digital programmable computer. ENIAC was the first electronic, Turing-complete device, and performed ballistics trajectory calculations for the United States Army.

Although the ENIAC was similar to the Colossus, it was much faster, more flexible, and it was Turing-complete. It combined the high speed of electronics with the ability to be programmed for many complex problems. It could add or subtract 5000 times a second, a thousand times faster than any other machine. It also had modules to multiply, divide, and square root. Built under the direction of John Mauchly and J. The principle of the modern computer was proposed by Alan Turing in his seminal 1936 paper, On Computable Numbers. Turing proposed a simple device that he called “Universal Computing machine” and that is now known as a universal Turing machine.