Evaluation on aids of computation could be divided in three levels.
Era-1) Early devices which manipulated by hand include abacus B.C.3000, Napier’s bones, the slide rule A.C. 1600. Then mechanical Calculators - Pascal’s calculator A.C.1642, Jacquard’s loom 1801,Babbage’s difference engine (A.C.1822), Programmable machines Babbage’s analytical engine (1834), Hollerith’s punch card equipment (A.C.1890).
Era-2) Covers years 1920-1950: Atanasoff Barry Computer-ABC, 1942, Electromechanical MARK-I, 1944, First full-scale electronic computer ENIAC (1946), and Stored program computers UNIVAC (1951), first commercial computer IBM 650, 1954. First integrated circuit computer is operated on (1958), then main frames (1965). Minicomputer 1963. First personal computer 1977,
Era-3) Microprocessor age starts after 1980. The Pentium and multimedia technology came out in 1993. The World Wide Web and Internet browsers appeared in 1994.
The computer age begins Mark-I computer in 1944. Then the evaluation of computers classified by technological generations: First generation 1951-58 the vacuum tube, second generation 1959-64 the transistor, the third generation 1965-70 the Integrated Circuit, the forth generation 1971- Present, the micro-processor (1971) And Minicomputers (1975), Microcomputer (1981). Personal Computer age and network Mobil communication is sated.
Computer technology started as computing machine including the invention of transistors and development of integrated circuits, the establishment of communication satellites, and advance in optic technology. To day, desktop-size has more computing power than the room-size machines of the 1940s and can exchange Information quickly via global communication systems.
Computer machinery improved as modern computers by the use of microelectronics. Microelectronics made them law cost, high speed, and small in size. So computers may roughly classified by size and computing capacity: Mainframe computers have greater computing capacity then do personal computers.
They are varying in size and capability. Supercomputers are most powerful computers that are used for special cases as space research activities. Workstation has power between mid size mainframe and PC. Personal Computers go into different categories as Desktop, Laptop or Notebook, or Hand size-Palm Computer. Communication and computer Networks: At the mid of 1975 the major changing in computer usage was Communication be come network systems which link machines and people with companies and countries. After 1980’s PC be come as a network terminal. The computer networks are evaluated as Local Area Networks (LAN) and Wide Area Networks (WAN).