SCO Unix is unimportant. You left out Unixware. It is a critical part of the picture. I have forgotten the details, but SCO bought Unixware from somewhere. Unixware was the official UNIX Sys 5 rel 4 release and when SCO bought it, they bought all sorts of IP.
Unix was certainly developed at AT&T's Bell Labs by Ken Thompson kind of as a small Multics. Bill Joy and others developed Berkeley Unix which was based on Unix version 6. System V incorporated some BSD tools, such as vi and csh. AT&T sued BSDI when they released their versions of BSD Unix. I don't recall the details, but effectively BSDI won. The lawsuit paved the way for Linux because people believed that Linux had no AT&T code. (Had AT&T won, it would have also affected Linux). AT&T sold Unix (Unix System Labs) to Novell (If my memory is correct). The Unix brand was subsequently transfered to The Open Group ( http://www.opengroup.org/), a standards consortium that certifies Unix. For a vendor to be able to use the Unix name, it must first receive certification from The Open Group.
I think that Caldera/SCO is digging its own grave. IMHO, SCO was one of the worst Unix systems, and I've worked on Solaris, Tru64, Sun OS4, HP-UX, IRIX, and a few others.
-- Jerry Feldman
Boston Linux and Unix user group http://www.blu.org PGP key id:C5061EA9 PGP Key fingerprint:053C 73EC 3AC1 5C44 3E14 9245 FB00 3ED5 C506 1EA9
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