Computer definition

A computer is a machine, device or system that can be instructed (programmed) to perform sequences of arithmetic and logical operations on information (data), typically in a fast, accurate and efficient manner. A true computer is versatile and takes in two kinds of data - a set of instructions and the data to perform the commands on, and outputs the result to a specified location.

Most computers are electronic and work with digital data, but a few are mechanical, work directly with ternary (base-3) or analogue data. As a system a computer generally has at least three key sub-systems - a CPU or processor that has built in functions and conducts most of the work, at least one form of memory to hold data and commands and an Input/Output (I/O) where data can be taken to or from another device or system.