operating system

In computing, a program that controls the basic operation of a computer. A typical OS controls the peripheral devices such as printers, organizes the filing system, provides a means of communicating with the operator, and runs other programs.

Many operating systems are written to run on specific computers, but some are available from third-party software houses and will run on machines from a variety of manufacturers. Examples include Apple's Macintosh OS X, Microsoft's Windows, and Unix.

Unix (developed at AT&T's Bell Laboratories) is the standard on workstations, minicomputers, and supercomputers; it is also used on desktop PCs and mainframes. The relatively recent Linux is rapidly increasing in popularity.