Computers can be generally classified by size and power as follows:

computer: A small, single-user computer based on a microprocessor. In addition to the microprocessor, a Personal computer has a keyboard for entering data, a monitor for displaying information, and a storage device for saving data. Workstation: A powerful, single-user computer. A workstation is like a personal computer, but it has a more powerful microprocessor and a higher-quality monitor. Minicomputer: A multi-user computer capable of supporting from 10 to hundreds of users simultaneously. Mainframe: A powerful multi-user computer capable of supporting many hundreds or thousands of users simultaneously. Supercomputer: An extremely fast computer that can perform hundreds of millions of instructions per second.