Classification of Computers:

This classification of computer system is based upon the size of the memory, the speed and operating features of the computer systems. A variety of computer systems are now available in the market.

1.   Micro computer : It consist of a microprocessor chip as CPU (central processing unit), semiconductor ROM(Read only Memory) for storing only Essential programs for operating systems, RAM (Random Access Memory) for data storage mad input output devices like keyboard, printer etc. They have limited input and output capabilities, little software and little storage capacity as compared to the other types. Typical micro computers have a memory capacity of 64KB or 256 or 1 MB or even more.

Micro computers are used extensively as personal computers (PC’s). These are designed for the use of professionals. They were used for wide range of applications and hence they are called General purpose Computers. Many micro computer languages are used of various purposes. BASIC, COBOL, FORTRAN, PASCAL are included in them, IBMPC, APPLE I and III are the examples of typical micro computers.

2.    Mini Computers: These are faster than micro computers, the speed of CPU around the one million instructions per second. Digital Equipment Corporation (PDP-8 and PDP -11) is the largest manufacture of mini computers. HCL – HORIZAN, SN 23 are also manufactures of such computers. Fast line printers, large disk capacity disks, magnetic tapes are peripheral device used with mini computers.

3.   Main Frame Computers: These computers are manufactured in different models, capacities and prices they are faster than the mini computers. They are also called midi computers. The CPU speeds are range 1 to 10 million instructions per second and even more in many cases.  

4.  Super Computers: Super computers are also called Maxi – computers. They are high speed computers. The speed of such computers is more than 100 million instructions per second. Wide ranges of memory capacity models of this type or available. Various types of peripherals are connected to super computer systems. High speed disks printers 100 MB, high speed tapes are the examples of it.