UNIX was "created" 1969. UNIX time is kept from Jan 1, 1970.
Ken Thompson, Dennis Ritchie (AT&T Bell Labs), Multics, PDP7, PDP11.
The PDP11 was a 16-bit machine, so programs were restricted to 64kB, and this encouraged
modular programming and cooperating processes.
Dennis Ritchie wrote "C", a descendant of "B" and "BCPL".
Thompson and Ritchie rewrote the Unix kernel in "C" (1973) - greatly increased portability
6th edition of UNIX distributed in 1975. First version with widespread use outside AT&T.
7th edition distributed in 1978. Unix ported to VAX at AT&T, and to Interdata 8/32 and 7/32, and the IBM VM/370.
This gave Unix a 32-bit address space (4GB).
University of California, Berkeley -- BSD UNIX (Berkeley Software Distribution), TCP/IP. BSD 4.4 and
later spinoffs (FreeBSD/NetBSD/OpenBSD)
are free of AT&T code restrictions.
AT&T SVR4 API spec, POSIX, XPG4
Today there are many "flavors" of UNIX's with slight differences. Commercial versions (IRIX, Solaris, AIX, HPUX etc.)
mostly derived from SVR4 codebase.
Largest growth recently is in Linux, an open source implementation of Unix developed by Linus Torvalds
(and supporting cast of thousands)
The name "UNIX" is a trademark, originally of AT&T, but since sold several
times - most variants have names other than "UNIX", but all derive from AT&T code
or API specifications originally.
