Editing Unix wars

{{short description|Struggles between Unix vendors to set the standard for Unix}}
{{More citations needed|date=December 2009}}
{{Use mdy dates|date=April 2023}}
[[File:Unix timeline.en.svg|thumb|450px|Unix genealogy tree]]

The '''Unix wars''' were struggles between vendors to set a standard for the [[Unix]] [[operating system]] in the late 1980s and early 1990s.

==Origins==
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.<ref name="fiedler198310">{{cite news | url=https://archive.org/stream/byte-magazine-1983-10/1983_10_BYTE_08-10_UNIX#page/n133/mode/2up | title=The Unix Tutorial / Part 3: Unix in the Microcomputer Marketplace | work=BYTE | date=October 1983 | access-date=30 January 2015 | author=Fiedler, Ryan | pages=132}}</ref> In the mid-1980s, the three common versions of Unix were AT&T's [[UNIX System III|System III]], the basis of [[Microsoft]]'s [[Xenix]] and the IBM-endorsed [[PC/IX]], among others; AT&T's [[UNIX System V|System V]], which it sought to establish as the new Unix standard;<ref name="shea19840220">{{cite news | url=https://books.google.com/books?id=hS4EAAAAMBAJ&pg=PA43 | title=New developments may decide battle over Unix | work=InfoWorld | date=1984-02-20 | access-date=25 February 2016 | author=Shea, Tom | pages=43–45 | archive-date=2021-02-16 | archive-url=https://web.archive.org/web/20210216064125/https://books.google.com/books?id=hS4EAAAAMBAJ&pg=PA43 | url-status=live }}</ref> 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,<ref name="rdbmsinformix20070612">{{Cite interview |interviewer=Luanne Johnson |title=RDBMS Workshop: Informix |url=https://archive.computerhistory.org/resources/access/text/2013/05/102702566-05-01-acc.pdf |access-date=2025-05-30 |publisher=Computer History Museum |date=2007-06-12 |pages=13, 30}}</ref> while rival [[Ingres (database)|Ingres]] supported more than 40 systems.<ref name="rdbmsingressybase20070613">{{Cite interview |interviewer=Doug Jerger |title=RDBMS Workshop: Ingres and Sybase |url=https://archive.computerhistory.org/resources/access/text/2013/05/102702565-05-01-acc.pdf |access-date=2025-05-30 |publisher=Computer History Museum |date=2007-06-13}}</ref> 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 vendors formed the [[X/Open]] [[open standard|standard]]s group in 1984 to promote compatible [[open system (computing)|open system]]s, 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 (computing)|crash]] by [[fuzz testing|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.<ref>{{Cite journal |last1=Miller |first1=Barton P. |first2=Louis |last2=Fredriksen |first3=Bryan |last3=So |title=An empirical study of the reliability of UNIX utilities |journal=[[Communications of the ACM]] |volume=33 |issue=12 |year=1990 |pages=32–44 |url=http://ftp.cs.wisc.edu/paradyn/technical_papers/fuzz.pdf |doi=10.1145/96267.96279 |s2cid=14313707 |access-date=2015-09-10 |archive-date=2018-10-24 |archive-url=https://web.archive.org/web/20181024163412/http://ftp.cs.wisc.edu/paradyn/technical_papers/fuzz.pdf |url-status=live }}</ref>

==Standardization==
The 1988 [[POSIX]] standard initially concentrated on system [[C library]] functions beyond what was included in the forthcoming C standard; later it expanded to specify other aspects of the system environment. POSIX specified a "lowest common denominator" that could be met by both System V and BSD-based variants, as well as some non-Unix systems, with a reasonable amount of effort.

In March 1993, the major participants in UI and OSF formed the [[Common Open Software Environment]] (COSE) alliance, effectively marking the end of the most significant era of the Unix wars. In June, AT&T sold its Unix assets to [[Novell]], and in October Novell transferred the Unix brand to X/Open.

In 1996, X/Open and the new OSF merged to form the [[Open Group]]. COSE work such as the [[Single UNIX Specification]], the current standard for branded Unix, is now the responsibility of the Open Group, which also controls the current POSIX standards.

Since then, occasional bursts of Unix factionalism have broken out, such as the [[Hewlett-Packard|HP]]/SCO "[[3DA]]" alliance in 1995, and [[Project Monterey]] in 1998, a teaming of [[IBM]], [[Santa Cruz Operation|SCO]], [[Sequent Computer Systems|Sequent]], and [[Intel]] which was followed by litigation ([[SCO v. IBM]]) between IBM and the [[The SCO Group|new SCO, formerly Caldera]].

==BSD and the rise of Linux==
BSD worked to purge copyrighted AT&T code from their version between 1989 and 1994. During this time, various open-source BSD x86 derivatives took shape, starting with [[386BSD]], which was soon succeeded by [[FreeBSD]] and [[NetBSD]]. [[OpenBSD]] emerged in 1995 as a fork of NetBSD, and [[DragonFly BSD]] as a fork from FreeBSD in 2003. [[Mac OS X v10.5]] is the first operating system with open source BSD code to be certified as fully Unix compliant.<ref>{{Cite web |url=http://www.opengroup.org/comm/press/19-2-nov07.htm |title=Mac OS X Leopard Achieves UNIX 03 Product Standard Certification |access-date=2009-07-28 |archive-date=2011-06-09 |archive-url=https://web.archive.org/web/20110609195918/http://www.opengroup.org/comm/press/19-2-nov07.htm |url-status=live }}</ref> BSD systems can claim direct ancestry from [[Version 7 Unix]]. According to Open Source advocate [[Eric Raymond]], BSD systems can be considered "genetic Unix", if not "trademark Unix".<ref>{{Cite web | url=http://www.internetnews.com/dev-news/print.php/2208691 | title=Microsoft Buys into SCO Group's Unix | access-date=2009-03-20 | archive-date=2009-08-17 | archive-url=https://web.archive.org/web/20090817191424/http://www.internetnews.com/dev-news/print.php/2208691 | url-status=live }}</ref>

During the ''[[UNIX System Laboratories, Inc. v. Berkeley Software Design, Inc.]]'' lawsuit (1992–94),<ref name="832 F.Supp. 790">{{cite court |litigants=Unix System Laboratories v. Berkeley Software |vol=832 |reporter=F. Supp. |opinion=790 |court=[[United States District Court for the District of New Jersey|D.N.J.]] |date=1993 |url=https://www.leagle.com/decision/19931622832fsupp79011506 }}</ref> the nearly-complete [[GNU]] operating system was made operational by the inclusion of the [[Linux kernel]] and lumped together under the label "[[Linux]]". GNU had been written from scratch to avoid copyright issues. Linux systems broadly aim for compatibility with [[POSIX]].

==See also==
* [[Editor war]]

==References==
{{Reflist}}

==Sources==
* [http://livinginternet.com/i/iw_unix_war.htm Unix Wars] (Living Internet)
* [http://www.bell-labs.com/history/unix/wars.html The UNIX Wars] {{Webarchive|url=https://web.archive.org/web/20040218042959/http://www.bell-labs.com/history/unix/wars.html |date=2004-02-18 }} (Bell Labs)
* [http://www.unix.org/what_is_unix/history_timeline.html The UNIX System{{snd}} History and Timeline] (The Open Group)
* [http://www.faqs.org/docs/artu/ch17s02.html Unix Standards] {{Webarchive|url=https://web.archive.org/web/20070929132152/http://www.faqs.org/docs/artu/ch17s02.html |date=2007-09-29 }} ([[Eric S. Raymond]], ''[[The Art of Unix Programming]]'')
* [http://www.groklaw.net/article.php?story=20050601125916588 Chapter 11. OSF and UNIX International] ([[Peter H. Salus]], ''The Daemon, the GNU and the Penguin'')

[[Category:Unix history]]
[[Category:Software wars]]
[[Category:Unix standards]]