Computer - Wikipedia. A computer is a device that can be instructed to carry out an arbitrary set of arithmetic or logical operations automatically. The ability of computers to follow a sequence of operations, called a program, make computers very flexible and useful. Such computers are used as control systems for a very wide variety of industrial and consumer devices. This includes simple special purpose devices like microwave ovens and remote controls, factory devices such as industrial robots and computer assisted design, but also in general purpose devices like personal computers and mobile devices such as smartphones. The Internet is run on computers and it connects millions of other computers. 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. More sophisticated electrical machines did specialized analog calculations in the early 2. The first digital electronic calculating machines were developed during World War II. The speed, power, and versatility of computers increased continuously and dramatically since then, to the point that artificial intelligence may become possible in the future. Conventionally, a modern computer consists of at least one processing element, typically a central processing unit (CPU), and some form of memory. The processing element carries out arithmetic and logical operations, and a sequencing and control unit can change the order of operations in response to stored information. Peripheral devices include input devices (keyboards, mice, joystick, etc.), output devices (monitor screens, printers, etc.), and input/output devices that perform both functions (e. Peripheral devices allow information to be retrieved from an external source and they enable the result of operations to be saved and retrieved. Etymology. According to the Oxford English Dictionary, the first known use of the word . The word continued with the same meaning until the middle of the 2. From the end of the 1. The Online Etymology Dictionary states that the use of the term to mean . The earliest counting device was probably a form of tally stick. Later record keeping aids throughout the Fertile Crescent included calculi (clay spheres, cones, etc.) which represented counts of items, probably livestock or grains, sealed in hollow unbaked clay containers. The Roman abacus was developed from devices used in Babylonia as early as 2. BC. Since then, many other forms of reckoning boards or tables have been invented. In a medieval European counting house, a checkered cloth would be placed on a table, and markers moved around on it according to certain rules, as an aid to calculating sums of money. It was discovered in 1. Antikythera wreck off the Greek island of Antikythera, between Kythera and Crete, and has been dated to circa 1. BC. Devices of a level of complexity comparable to that of the Antikythera mechanism would not reappear until a thousand years later. Many mechanical aids to calculation and measurement were constructed for astronomical and navigation use. The planisphere was a star chart invented by Ab. A combination of the planisphere and dioptra, the astrolabe was effectively an analog computer capable of working out several different kinds of problems in spherical astronomy. An astrolabe incorporating a mechanical calendar computer. It is a hand- operated analog computer for doing multiplication and division. As slide rule development progressed, added scales provided reciprocals, squares and square roots, cubes and cube roots, as well as transcendental functions such as logarithms and exponentials, circular and hyperbolictrigonometry and other functions. Aviation is one of the few fields where slide rules are still in widespread use, particularly for solving time. To save space and for ease of reading, these are typically circular devices rather than the classic linear slide rule shape. A popular example is the E6. B. In the 1. 77. 0s Pierre Jaquet- Droz, a Swiss watchmaker, built a mechanical doll (automata) that could write holding a quill pen. By switching the number and order of its internal wheels different letters, and hence different messages, could be produced. In effect, it could be mechanically . Campuses in Belleville, Granite City, and Red Bud. Registration, admissions, financial aid and scholarships, distance learning, counseling.Along with two other complex machines, the doll is at the Mus. 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. In 1. 87. 6 Lord Kelvin had already discussed the possible construction of such calculators, but he had been stymied by the limited output torque of the ball- and- disk integrators. The torque amplifier was the advance that allowed these machines to work. Clovis Community College is an institution of higher education offering instruction at the Associate degree level. The College provides accessible, affordable. News items, upcoming events, admissions requirements, faculty listing and publications. Penn Foster offers practical, affordable programs for high school, college, and career school. Your education is here. Learn about our programs today. Earn your Penn State degree online. Penn State's World Campus offers accredited online college degrees and certificate programs. Learn more about our online. Starting in the 1. Vannevar Bush and others developed mechanical differential analyzers. First computing device. Charles Babbage, an English mechanical engineer and polymath, originated the concept of a programmable computer. After working on his revolutionary difference engine, designed to aid in navigational calculations, in 1. Analytical Engine, was possible. The input of programs and data was to be provided to the machine via punched cards, a method being used at the time to direct mechanical looms such as the Jacquard loom. For output, the machine would have a printer, a curve plotter and a bell. The machine would also be able to punch numbers onto cards to be read in later. The Engine incorporated an arithmetic logic unit, control flow in the form of conditional branching and loops, and integrated memory, making it the first design for a general- purpose computer that could be described in modern terms as Turing- complete. All the parts for his machine had to be made by hand . Eventually, the project was dissolved with the decision of the British Government to cease funding. Babbage's failure to complete the analytical engine can be chiefly attributed to difficulties not only of politics and financing, but also to his desire to develop an increasingly sophisticated computer and to move ahead faster than anyone else could follow. Nevertheless, his son, Henry Babbage, completed a simplified version of the analytical engine's computing unit (the mill) in 1. He gave a successful demonstration of its use in computing tables in 1. Analog computers. During the first half of the 2. However, these were not programmable and generally lacked the versatility and accuracy of modern digital computers. The differential analyser, a mechanical analog computer designed to solve differential equations by integration using wheel- and- disc mechanisms, was conceptualized in 1. James Thomson, the brother of the more famous Lord Kelvin. Hazen and Vannevar Bush at MIT starting in 1. This built on the mechanical integrators of James Thomson and the torque amplifiers invented by H. A dozen of these devices were built before their obsolescence became obvious. By the 1. 95. 0s the success of digital electronic computers had spelled the end for most analog computing machines, but analog computers remained in use during the 1. Digital computers. Electromechanical. By 1. 93. 8 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. During World War II similar devices were developed in other countries as well. These devices had a low operating speed and were eventually superseded by much faster all- electric computers, originally using vacuum tubes. The Z2, created by German engineer Konrad Zuse in 1. It was quite similar to modern machines in some respects, pioneering numerous advances such as floating point numbers. Rather than the harder- to- implement decimal system (used in Charles Babbage's earlier design), using a binary system meant that Zuse's machines were easier to build and potentially more reliable, given the technologies available at that time. The engineer Tommy Flowers, working at the Post Office Research Station in London in the 1. Experimental equipment that he built in 1. Berry of Iowa State University developed and tested the Atanasoff. The German encryption machine, Enigma, was first attacked with the help of the electro- mechanical bombes. To crack the more sophisticated German Lorenz SZ 4. Army communications, Max Newman and his colleagues commissioned Flowers to build the Colossus. It had paper- tape input and was capable of being configured to perform a variety of boolean logical operations on its data, but it was not Turing- complete. Nine Mk II Colossi were built (The Mk I was converted to a Mk II making ten machines in total). Colossus Mark I contained 1. Mark II with 2. 40. Mark 1, greatly speeding the decoding process. Although the ENIAC was similar to the Colossus it was much faster and more flexible. Like the Colossus, a . Once a program was written, it had to be mechanically set into the machine with manual resetting of plugs and switches. It combined the high speed of electronics with the ability to be programmed for many complex problems. It could add or subtract 5. It also had modules to multiply, divide, and square root. High speed memory was limited to 2. Built under the direction of John Mauchly and J. Presper Eckert at the University of Pennsylvania, ENIAC's development and construction lasted from 1. The machine was huge, weighing 3. Turing proposed a simple device that he called . He proved that such a machine is capable of computing anything that is computable by executing instructions (program) stored on tape, allowing the machine to be programmable. The fundamental concept of Turing's design is the stored program, where all the instructions for computing are stored in memory.
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