Definition of Operating System
An Operating System is a software program or set of programs that mediate access between physical devices (such as a keyboard, mouse, monitor, disk drive or network connection) and application programs (such as a word processor, World-Wide Web browser or electronic mail client).
Some characteristics of an Operating System are:
- Whether multiple programs can run on it simultaneously: multi-tasking
- Whether it can take advantage of multiple processors: multi-processing
- Whether multiple users can run programs on it simultaneously: multi-user
- Whether it can reliably prevent application programs from directly accessing hardware devices: protected
- Whether it has built-in support for graphics.
- Whether it has built-in support for networks.
Some popular Operating System's are:
- Unix: multi-tasking, multi-processing, multi-user, protected, with built-in support for networking but not graphics.
- Windows NT: multi-tasking, multi-processing, single-user, protected, with built-in support for networking and graphics.
- Windows 95/98: multi-tasking, multi-processing, single-user, unprotected, with built-in support for networking and graphics.
- Windows 3.x: single-tasking, single-processing, single-user, unprotected, with built-in support for graphics but not networking.
- DOS: single-tasking, single-processing, single-user, unprotected with no built-in support for graphics or networking.
- NetWare: multi-tasking, multi-processing, single-user, unprotected, with built-in support for networking but not graphics.