The University of California at Berkeley acquired Version 4 of UNIX in 1974. In 1975, during a sabbatical leave from Bell Labs, Ken Thompson went to Berkeley and helped install UNIX Version 6 on a PDP-11/70. ``The same year, two graduate students also arrived at Berkeley: Bill Joy and Chuck Haley" [p. 5]RT:UNIX : they were to play an important role in the BSD developments.
Joy wrote the vi editor, and the C shell. Bill Joy is also one of the co-founders of Sun Microsystems.
In 1978, 2BSD was released.
In 1979, a combination of improved 2BSD and UNIX Version 7 was released as 3BSD.
DARPA (the Defence Advanced Research Project Agency) funded the development of 4BSD and 4.1BSD. The Fast File System was included in 4.2BSD which was released in 1983.
Finally, 4.3BSD was released in 1987.
Berkeley stopped development of its BSD UNIX with the release of its last version, 4.4BSD, in 1992.