Berkeley Software Distribution
(BSD) A family of Unix versions developed by Bill Joy and others at the University of California at Berkeley, originally for the DEC VAX and PDP-11 computers, and subsequently ported to almost all modern general-purpose computers. BSD Unix incorporates paged virtual memory, TCP/IP networking enhancements and many other features.
BSD UNIX 4.0 was released on 1980-10-19. The BSD versions (4.1, 4.2, and 4.3) and the commercial versions derived from them (SunOS, ULTRIX, Mt. Xinu, Dynix) held the technical lead in the Unix world until AT&T's successful standardisation efforts after about 1986, and are still widely popular.
See also Berzerkeley, USG Unix.