An interactive time-sharing system invented in 1969 by Ken Thompson
after Bell Labs left the Multics project, originally so he could play games
on his scavenged PDP-7. Dennis Ritchie, the inventor of C, is considered a
co-author of the system. The turning point in Unix's history came
when it was reimplemented almost entirely in C during 1972-1974,
making it the first source-portable OS. Unix subsequently underwent
mutations and expansions at the hands of many different people,
resulting in a uniquely flexible and developer-friendly environment.
By 1991, Unix had become the most widely used multiuser
general-purpose operating system in the world. Many people consider
this the most important victory yet of hackerdom over industry
opposition (but see Unix weenie and Unix conspiracy for an
opposing point of view). See Version 7, BSD, USG Unix,
Linux.
Some people are confused over whether this word is appropriately
`UNIX' or `Unix'; both forms are common, and used interchangeably.
Dennis Ritchie says that the `UNIX' spelling originally happened in
CACM's 1974 paper "The UNIX Time-Sharing System" because "we had a
new typesetter and troff had just been invented and we were
intoxicated by being able to produce small caps." Later, dmr tried
to get the spelling changed to `Unix' in a couple of Bell Labs
papers, on the grounds that the word is not acronymic. He failed,
and eventually (his words) "wimped out" on the issue. So, while the
trademark today is `UNIX', both capitalizations are grounded in
ancient usage; the Jargon File uses `Unix' in deference to dmr's
wishes.