A Brief History of Unix, BSD and FreeBSD

• Unix is now well over 20 years old.
• It was developed and refined by Ken Thompson, Dennis Ritche et al. at AT&T Bell Laboratories.
• Versions up to 7th Edition were made available to academic institutions for a small price.
• After a large reorganisation of AT&T, Unix was commercially marketed by Unix System Laboratories (USL), now owned by Novell.
• The University of California, Berkeley used Unix as a research system. It also had a DARPA grant to develop and implement the Arpanet protocols, which became TCP/IP.
• UCB distributed its changes to Unix to other owners of Unix. These were known as the Berkeley Software Distributions.
• UCB added many features to Unix:
  • Better memory management.
  • Job control.
  • A fast and robust file system.
  • Networking (TCP/IP).
• By 1989, UCB had rewritten so much of the AT&T Unix code that only 5 -- 10% of the BSD Unix code was in fact original AT&T code.
• The non-AT&T code was released as the Net/2 distribution.
• Several people decided to rewrite the missing code from scratch. Bill Jolitz completed the Net/2 code for the i386 PC platform, 386BSD, and gave his code back to UCB.
• Similarly, Berkeley Software Design, Inc. (BSDI) completed the Net/2 code for the i386 PC platform, using much of Bill's code.
• By now, AT&T were seriously concerned about the availability of non-AT&T Unix clones.
• In 1992, AT&T brought an injunction against BSDI and UCB because they believed the Net/2 distribution violated Unix trade secrets.
• After much legal wrangling, the issue was solved in February 1994, after USL had been sold to Novell.
• UCB can freely distribute its latest BSD version, 4.4, with some files removed. This is known as 4.4BSD-Lite.
• The perceived lack of support for 386BSD by Bill Jolitz lead two groups to take 386BSD and maintain it. Thus, FreeBSD and NetBSD were born.
• The legal settlement has forced both camps to move to 4.4BSD-Lite as the basis for their systems, which is better then Net/2 anyway.