The Computer Systems Research Group was the team at the University of California, Berkeley that guided the Berkeley Software Distribution of Unix. Marshall Kirk McKusick, a member of the group, recounts its history in “Twenty Years of Berkeley Unix,” a firsthand chapter in the book Open Sources. Unix first arrived at Berkeley in January 1974, and over the following years students and staff extended it heavily.
The group was formally established in April 1980 under funding from the Defense Advanced Research Projects Agency (DARPA), which wanted a common operating system for its research community. Bill Joy led much of the early development; McKusick describes how in early 1980 Joy took charge of the further development of Unix at Berkeley.
Under DARPA’s sponsorship the CSRG built the work that made BSD historically important, above all the integration of the TCP/IP networking protocols and the sockets programming interface that became the standard way to write networked software. Berkeley releases such as 4.2BSD and 4.3BSD spread these ideas across universities and companies.
McKusick records that the group released “Networking Release 1” in June 1989 as the first freely redistributable Berkeley code, work that eventually led to the modern free BSD systems. The CSRG was disbanded after the release of 4.4BSD-Lite, Release 2 in June 1995, closing two decades of Berkeley Unix development.