What is Unix?

Unix, officially trademarked as UNIX and sometimes also written as Unix with small caps, is a multiuser, multi-tasking operating system that originated at Bell Labs in 1969 as an interactive time-sharing system. It was written entirely in the C programming language, which made it more easily ported between different hardware platforms. The Internet was originally built entirely upon Unix-based servers.

Today's Unix has evolved as a kind of large freeware product, with many extensions and new ideas provided in a variety of versions of Unix by different companies, universities, and individuals. And due to its portability, flexibility, and power, UNIX has become a leading operating system for workstations.

Unix now is also owned as a trademark by The Open Group, which oversees its develop and publishes the Single UNIX® Specification. Only systems fully compliant with and certified according to the Single UNIX Specification are qualified to use the trademark; others are called "Unix system-like" or "Unix-like" (though the Open Group disapproves of this term).

See: Linux, OS/2