Classifications of Computers


 The first four generations of computers were based on the technology of the age to which they belonged. They were thus based on the vaccum tube technology;the transistor and printer circuit technology; the integrated circuit technology and the Very large Scale Integrated (VLSI) technology, respectively. The Marvel of the fourth generation VLSI technology is that a microchip weighing a few grams - a thin silicon chip using 0.13 micron technology (SDRAM)has a memory capacity of one Gigabyte (10⁹ or 100 crores or bits of 0s and 1s equivalent of 8,000 newspaper pages). (Note:bit is an abbreviation for the binary digit). Presently the development has entered areas of "Artificial Intelligence." These are generally called Fifth generation computers. 


Today computers can be classified as 


Main frame computers. 

Mini-computers. 

Micro-computers. 



Main frame computers

Main frame computers are expensive, large, centralised computer facilities where a super computer(like the CRAY or PARAM or CYBER) or a large computer (like the Dec 10, IBM S390 models etc.) is connected to several terminals. A multi-user mainframe computer has a large memory and is capable of speeds of the order of several billions of floating-point operations per second (Flops). 




Mini-Computers

Mini-Computers are also multi-user computers comparatively operating at slower speeds and lesser memory. In the mini-computer category are the extremely popular Dec10, PDP-11 and the Vax-11 computers of t Digital Equipment Corporation (Dec). 




Micro-Computers

Micro-Computers are based on standard micro-processor marketed by Intel, Motorola, etc. A micro-processor is a single silicon electronic chip which contains the ALU and the control unit. Micro computers are often called Personal Computers or PCs since they were originally intended to be single user devices either at office or at home. The home Computer is a PC providing education , entertainment, information and communication facility at home. Now-a-days one can send email/e-greetings, chat, play music/play video/games, do-shopping and banking operations with the help of a home PC and internet without leaving one's him.