UNDERSTANDING COMPUTER SYSTEM

                         COMPUTER


 computer, device capable of performing a series of arithmetic or logical operations. A computer is distinguished from a calculating machine, such as an electronic calculator, by being able to store a computer program (so that it can repeat its operations and make logical decisions), by the number and complexity of the operations it can perform, and by its ability to process, store, and retrieve data without human intervention. Computers developed along two separate engineering paths, producing two distinct types of computer-analog and digital. An analog computer operates on continuously varying data; a digital computer performs operations on discrete data. 

Computers are categorized by both size and the number of people who can use them concurrently. supercomputers are sophisticated machines designed to perform complex calculations at maximum speed; they are used to model very large dynamic systems, such as weather patterns. Mainframes, the largest and most powerful general-purpose systems, are designed to meet the computing needs of a large organization by serving hundreds of computer terminals at the same time. Minicomputers, though somewhat smaller, also are multiuser computers, intended to meet the needs of a small company by serving up to a hundred terminals. Microcomputers, computers powered by a microprocesser, are subdivided into personal computer and workstations, the latter typically incorporating RISC. processor Although microcomputers were originally single-user computers, the distinction between them and minicomputers has blurred as microprocessors have become more powerful. Linking multiple microcomputers together through a local area network or by joining multiple microprocessors together in a parallel-processing system has enabled smaller systems to perform tasks once reserved for mainframes, and the techniques of gird computing have enabled computer                 utilize the unemployed processing power of connected computers.