Early digital computers were electromechanical; electric switches drove mechanical relays to perform the calculation. These devices had a low operating speed and were eventually superseded by much faster all-electric computers, originally using vacuum tubes.

A computer is an electronic device that manipulates information, or data. It has the ability to store, retrieve, and process data. You may already know that you can use a computer to type documents, send email, play games, and browse the Web.

The different types of computers are Mainframe, Mini Computer, Micro Computer, Supercomputer, Analog, Digital, Hybrid.

Computer : is an electronic device that operates (works) under the control of programs stored in its own memory unit. A computer is an electronic machine that processes raw data to give information as output.