BSD

/B-S-D/ n. [abbreviation for `Berkeley System Distribution'] a family of UNIX versions for the DEC VAX and PDP-11 developed by Bill Joy and others at Berzerkeley starting around 1980, incorporating paged virtual memory, TCP/IP networking enhancements, and many other features. The BSD versions (4.1, 4.2, and 4.3) and the commercial versions derived from them (SunOS, ULTRIX, and Mt. Xinu) held the technical lead in the UNIX world until AT&T's successful standardization efforts after about 1986, and are still widely popular. See UNIX, USG UNIX.