Generally Computers are classified by size and power

The personal computer is a small, single-user computer based on a microprocessor, a keyboard for entering data, a monitor for displaying information, and a storage device for saving data.

A workstation is a powerful, single-user computer is like a personal computer, but has a more powerful microprocessor and a higher-quality monitor.

The minicomputer is a multi-user computer capable of supporting from 10 to hundreds of users simultaneously.

Mainframe computers are powerful multi-user computers capable of supporting many hundreds or thousands of users simultaneously.

The supercomputer is an extremely fast computer, it can perform hundreds of millions of instructions per second.

Computers have revolutionized the business environment with assistance of many time-consuming, complex tasks such as accounting, inventory control, customer databases, shipping control, and financial analysis.