A Brief Synopsis of Unix History - University of Indiana Knowledge Base article. Summary of Unix versions and links to related entries. The full source archives of the University of California at Berkeley's Computer Systems Research Group, for sale on a 4-CD set. Dennis Ritchie's Home Page - Several historic technical reports, anecdotes, and stories from one of the fathers of Unix. Concentrates on the evolution of the file system, the process-control mechanism, and the idea of pipelined commands.
Some attention is paid to social conditions during the development of the system.
History of the BSD Daemon - Various drawings, pictures, and information on the red devil BSD mascot. The History of UNIX - Brief historical commentary with a graphical Unix family tree. Includes some utility sources. Mailing list and archives. Unix History - Very brief article from the IBM library.