a) Super Computer
- Super computers are the fastest, most-powerful and most expensive computers.
- It has the ability to recover automatically from failures.
- It has the ability to support several Giga Bytes of RAM.
- Unlike conventional computers, which have a single processor to process one instruction at a time, supercomputers have multiple processors (or CPUs) that process multiple instructions at a time.
- Supercomputers are widely used in scientific applications such as aerodynamic design and simulation, processing of geological data.
- One of the most powerful supercomputers today is "The Cray-2" and Some others are CRAY 1, CRAY - MP, SX-2, HITAC S-300, etc.
b) Mainframe Computer
- A mainframe computer is usually slower, less powerful and less expensive than supercomputers.
- Very large in size with approximately 1000 square ft area.
- Mainframes process several million instructions per second (MIPS). More than 1,000 remote workstations can be accommodated by a typical mainframe computer.
- Mainframes are used by banks and many businesses to update inventory, etc.
- Many modern mainframes have multiprocessing capabilities.
c) Mini Computer
- These are also a general purpose computer, smaller than mainframe computer. Medium sized computer, occupying approximately 10 sq ft of area.
- They have slower operating speed, smaller backup storage, limited hardware and less memory than mainframes.
- Minicomputers are well adapted for functions such as accounting, word processing, data base management, statistical packages for social sciences
- More than 50 terminals and large storage capacity device than micro computers but smaller than mainframe computers. E.g. Prime 9755
d) Micro Computer
- A microcomputer is the smallest, least expensive of all the computers.
- Microcomputers have smallest memory and less power
- Microcomputers are also called personal computers.
- The most common type of microcomputer is a desktop computer, which is a non-portable personal computer.