Computer Systems Research Group

"CSRG" redirects here. For the defunct Chinese rolling stock manufacturer, see China South Locomotive and Rolling Stock Industry (Group) Corporation. For the World War I era machine gun, see Chauchat.

Simplified evolution of Unix systems. The Mach kernel was a fork from BSD 4.3 that led to NeXTSTEP / OpenStep, upon which macOS and iOS are based.

The Computer Systems Research Group (CSRG) was a research group at the University of California, Berkeley, that was dedicated to enhancing AT&T Unix operating system and funded by the Defense Advanced Research Projects Agency.

History

Professor Bob Fabry of Berkeley acquired a UNIX source license from AT&T in 1974. His group started to modify UNIX, and distributed their version as the Berkeley Software Distribution (BSD).

In April 1980, Fabry signed a contract with DARPA to develop UNIX even further and accommodate the specific requirements of the ARPAnet. With this funding, Fabry created the Computer Systems Research Group.

By the early 1980s, CSRG was the best-known non-commercial Unix developer, and a majority of Unix sites used at least some Berkeley software. AT&T included some CSRG work in Unix System V.

During the 1970s and 1980s, AT&T/USL raised the commercial licensing fee for UNIX from $20,000 to $100,000–$200,000. 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. They succeeded in 1994, but AT&T disagreed and sued Berkeley. After a court settlement in 1994, CSRG distributed the final version of BSD, called 4.4BSD-Lite2.

The group disbanded in 1995.

Innovations

CSRG made significant innovations, advancing the state of the art and influencing the design of other operating systems. For example, the sockets API remains in use in many operating systems today.

• The Berkeley Sockets API solved the problem of supporting multiple protocols (e.g. XNS and TCP/IP), and partially extended UNIX's "everything is a file" notion to these network protocols.

• The Berkeley 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.

• Job control signals allowed a user to suspend a job with a key-press (control-Z), and then continue running the job in the background under the C shell.

Significant releases

Noteworthy releases of BSD were:

• 3.0 BSD, the first version to support virtual memory.
• 4.0 BSD, which included the job-control functionality (CTRL-Z), to suspend and restart a running job.
• 4.15 (interim) BSD, a special version which used BBN's TCP/IP stack.
• 4.2 BSD, which included BSD's own, full, TCP/IP stack, FFS, and NFS support.

Legacy

CSRG left 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 formatting style of C source code in their kernels. This style is known as KNF (Kernel Normal Form) and is documented in BSD's style(9) man page.

Alongside the Free Software Foundation and Linux, the CSRG laid the foundations of the open source community.

Former members include Keith Bostic, Bill Joy, Marshall Kirk McKusick, Samuel J. Leffler, Özalp Babaoğlu and Michael J. Karels, among others. The corporations Sun Microsystems, Berkeley Software Design and Sleepycat Software (later acquired by Oracle) can be considered spin-off companies of CSRG. Berkeley Software Design was led by Robert Kolstad, who led the development of BSD Unix for supercomputers at Convex Computer.

See also

• Mach (kernel)

External links

• The Computer Systems Research Group 1979 — 1993
• A more detailed article
• Marshall Kirk McKusick (March 29, 1999). "Twenty Years of Berkeley Unix – From AT&T-Owned to Freely Redistributable". O'Reilly Media. Retrieved September 25, 2008.