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A computer in its rawest sense encompasses any apparatus capable of input, processing, and output. The most basic of these would be a slide rule and even a ramp which converts lateral force into height. A computer is classified into three main categories: electronical versus mechanical, general purpose versus special purpose, and digital versus analog. An electronic computer is composed of electrical circuits and transistors while a mechanical computer runs solely on springs and levers. A general purpose computer is designated for more broad and various functions. On the otherhand, a special purpose computer serves a more specific and unique function. Analog computers compute data continuously like a casette player while digital computers compute data discreetly, a cd player being its quintessential example. A digital computer refers to a device that uses a binary system measured by electronic current. Binary numbers are only inclusive of 0's and 1's. 0's switch it off and 1's switch it on. Analog refers to numerical values that have a continuous range. An analog computer consists of both 1's and 0's but everything in between and not exclusive of units. For example p, approximately 3.14, is an analog number. Consider a desk lamp which has an on/off switch. At any given moment the light has two functions either on or off. However if one replaces the on/off switch with a dimmer, the lamp is analog, because the lamp could be on/off and the amount of light can by all varying intensities in between. Analog computers were the first to be invented. A popular analog computer would be the slide rule which was first seen in the 1920's. The slide rule propagates calculations by sliding a gauged, narrow wooden strip through its rulerlike holder. Because the sliding and numerical values are continuous and has no mechanism to stop at one value in particular, the slide rule is analog. New interst has arised with analog computers especially in neural networks which correspond solely to continuous electronic signals. The majority of modern computers, however, are digital running on a finite number of states-on or off or 1's and 0's of bits. These bits are combined to denote a wide range of information such as letters, graphics, program instructions, and numbers. Whether analog or digital people employ computers in a vast variety of ways. Microcomputers encrypted throughout the electronic circuitry of most home appliances operate home security systems, regulate the indoor temperature, give the time, and turn dvd players off and on. In business, computers transfer funds electronically, track inventories with scanners and bar codes, and check a customer's credit status. In automobiles, computers control the fuel flow, thereby enhancing gas mileage. Computer applications, or programs, exist to supplement each and every educational level, from programs that educate sentence construction or simple arithmetic to advanced calculus. Teachers are enabled to prepare notes or a lesson plan and keep track of each individual's grades with computer aid. In conjunction, educators can use computer-controlled projection units to add sound, animation, and graphics to conduct lectures. Computers even entertain, generating computer-animated features or dubbing digitized sound on audio systems from a digitally coated laser disc. The military engages computers in sophisticated communication modes to keep track of munitions and personnel and to unscramble and encrypt messages. Computers are employed extensively in such scientific research as modeling systems that are too impractical or expensive to build freehand, such as experimenting with the air flow around prototypes of space shuttles, calculating complex mathematical problems, and displaying and storing complicated data. |
