Operating systems are the software necessary to enable the computer to function. They serve as the link between the user and the computer hardware. Operating systems consist of a standardized interface the user accesses, as well as instructions to hardware components such as |hard disks| and |peripherals| to optimize their performance. Examples of operating systems in common use today are OS/2, UNIX, DOS, Windows, and System 7. IBM PC and compatible computers generally use DOS (a ~command-line interface~) and Windows (a ~graphic interface~).
