What are System V Unix and SVR4?

Unix was born at AT&T's Bell Laboratories in the late 1960s. Development continued largely in house until the middle 1970s with the release of Version 6. At this time, AT&T was prevented by statute from developing Unix commercially, but instead licensed the code to other organizations and corporations. In the mid-1980s, AT&T did enter the commercial market and the ultimate result of this effort was System V, a more or less direct descendent of Version 7.

Compared to the other major Unix flavor, BSD, System V was more conservative and focused on open standards. It was favored by commercial enterprises, which contrasted with BSD's strength in the academic arena. However, in 1987, AT&T worked with Sun Microsystems to produce System V, revision 4 (SVR4), which incorporated elements of BSD and SunOS into System V. Most commercial Unix implementations are based on the SVR4 model, and it has also influenced Linux.

AT&T ceased development of System V when it sold its Unix holdings to Novell in 1993. Novell delivered control of the UNIX name to X/Open (now the Open Group) and after briefly marketing it as UnixWare, sold the rest of its System V interests to SCO.

Also see:

• In Unix, how can I display information about the operating system?
• Where can I learn about the history of Unix?