Both
AT&T Corporation and
University of California, Berkeley are important in the early
history of Unix. Although AT&T's
Bell Labs created
Unix, by the 1980s, Berkeley's
Computer Systems Research Group was the leading non-commercial Unix developer. In the mid-1980s, the three common versions of Unix were AT&T's
System III, the basis of
Microsoft's
Xenix and the IBM-endorsed
PC/IX, among others; AT&T's
System V, which it sought to establish as the new Unix standard; and the
Berkeley Software Distribution (BSD). All were derived from AT&T's
Research Unix but had diverged considerably. Further, each vendor's version of Unix was different to some degree. For example, by the late 1980s, database vendor
Informix Corporation developed software for more than 100 different Unix systems, and therefore had altogether over 1,000 versions of their products, while rival
Ingres supported more than 40 systems. At a mid-1980s
Usenix conference, AT&T staff had buttons that read "System V: Consider it Standard" and a number of major vendors were promoting products based on System V. On the other hand, System V did not yet have TCP/IP networking built-in, while BSD 4.2 did; vendors of engineering workstations were nearly all using BSD, and posters reading "4.2 > V" were available. Several European vendors formed the
X/Open standards group in 1984 to promote compatible
open systems, and they chose to base their system on Unix. X/Open caught AT&T's attention. To increase the uniformity of Unix, AT&T and leading BSD Unix vendor
Sun Microsystems started work in 1987 on a unified system. (The feasibility of this had been demonstrated a few years earlier by the
US Army Ballistic Research Laboratory's System V environment for BSD Unix.) This was released in 1988 as
System V Release 4 (SVR4). While this decision was applauded by customers and the trade press, certain other Unix licensees feared Sun would be unduly advantaged. They formed the
Open Software Foundation (OSF) in 1988. The same year, AT&T and another group of licensees responded by forming
Unix International (UI). Technical issues soon took a back seat to vicious and public commercial competition between the two "open" versions of Unix, with X/Open holding the middle ground. A 1990 study of various Unix versions' reliability found that in each version, between a quarter and a third of operating system utilities could be made to
crash by
fuzzing; the researchers attributed this, in part, to the "race for features, power, and performance" resulting from BSD–System V rivalry, which left developers little time to worry about reliability. An industry analyst nonetheless said that despite OSF and UI's fierce rivalry, "Two Unixes are a lot better than 225 — which is what we have had until now". ==Standardization==