Computer Systems Research Group

In April 1980, Fabry signed a contract with DARPA to develop UNIX even further and accommodate the specific requirements of the ARPAnet.

The sockets interface solved the problem of supporting multiple protocols (e.g. XNS and TCP/IP), and extended UNIX's "everything is a file" notion to these network protocols, while the Fast File System increased the block allocation size from 512 bytes to 4096 bytes (or larger), improving disk transfer performance, while also allowing "micro-blocks" as small as 128 bytes, which improved disk use.

This became a big problem for small research labs and companies who used BSD, and the CSRG decided to replace all the source code that originated from AT&T.

The group was disbanded in 1995, leaving a significant legacy: FreeBSD, OpenBSD, NetBSD, and DragonFly BSD are based on the 4.4BSD-Lite distribution and continue to play an important role in the open-source UNIX community today, including dictating the style of C programming used via KNF in the style man page.

Former members include Keith Bostic, Bill Joy, Marshall Kirk McKusick, Samuel J. Leffler, Özalp Babaoğlu and Michael J. Karels, among others.