Xenix: Difference between revisions

| latest release date = {{Start date and age|19891991}}

| website = N/A

'''Xenix''' is a discontinued version of the [[Unix]] [[operating system]] for various [[microcomputer]] platforms, licensed by [[Microsoft]] from [[AT&T Corporation]] in the late 1970s. The [[Santa Cruz Operation]] (SCO) later acquired exclusive rights to the software, and eventually replaced it with SCO UNIX (now known as [[OpenServer|SCOXinuos OpenServer]]).

In the mid-to-late 1980s, Xenix was the most common Unix variant, measured according to the number of machines on which it was installed.<ref name="kelleher">{{cite news |newspaper=[[Computerworld]] |title=Corporate Unix: A system struggles to earn its stripes |date=February 3, 1986 |author-first=Joanne |author-last=Kelleher |url=https://books.google.com/books?id=UE1HODexHKoC&pg=PA44 |page=44}}</ref><ref>{{cite book |author-last1=Leffler |author-first1=Samuel J. |author-first2=Marshall Kirk |author-last2=McKusick |author-link2=Marshall Kirk McKusick |author-first3=Michael J. |author-last3=Karels |author-link3=Michael J. Karels |author-first4=John S. |author-last4=Quarterman |title=The Design and Implementation of the 4.3BSD UNIX Operating System |date=October 1989 |publisher=[[Addison-Wesley]] |isbn=0-201-06196-1 |page=[https://archive.org/details/designimplementa0000unse/page/7 7] |url=https://archive.org/details/designimplementa0000unse/page/7 |url-access=registration}}</ref>

[[Bell Labs]], the developer of Unix, was part of the regulated [[Bell System]] and could not sell Unix directly to most end users (academic and research institutions excepted); it could, however, license it to software vendors who would then resell it to end users (or their own resellers), combined with their own added features. Microsoft, which expected that Unix would be its operating system of the future when personal computers became powerful enough,{{r|letwin19950817}} purchased a license for [[Version 7 Unix]] from AT&T in 1978,<ref>{{cite book |author-first=Steve D. |author-last=Pate |title=Unix Internals: A Practical Approach |date=1996 |publisher=[[Addison Wesley Professional]] |isbn=978-0-201-87721-2 |quoteurl=https://archive.org/details/unixinternalspra0000pate |url-access=registration}} p. 9 "Microsoft licensed Seventh Edition Unix from AT&T in 1978 to produce the Xenix operating system initially for the PDP-11." |page=9}}</ref> and announced on August 25, 1980, that it would make the software available for the [[16-bit]] microcomputer market.<ref>{{Cite web|url=http://channel9.msdn.com/Series/History/The-History-of-Microsoft-1980|title=The History of Microsoft - 1980}}</ref> Because Microsoft was not able to license the "Unix" name itself,<ref>{{cite web |url=http://www.computerhope.com/unix/xenix.htm |title=Xenix variant information |date=February 26, 2010 |quote=In the late 1970s Microsoft licensed Unix source code from AT&T, which at the time was not licensing the name Unix. |url-status=dead |archive-url=https://web.archive.org/web/20131219145551/http://www.computerhope.com/unix/xenix.htm |archive-date=December 19, 2013}}</ref> the company gave it an original name.

Intel sold complete computers with Xenix under their Intel [[System 86]] brand (with specific models such as 86/330 or 86/380X); they also offered the individual boards that made these computers under their [[iSBC]] brand.<ref>{{cite web |url=http://bitsavers.informatik.uni-stuttgart.de/pdf/intel/system3xx/172758-001_Introduction_to_the_System_86_330_and_380_Systems_Mar83.pdf |title=Introduction to the System 86/360 and System 86/330A Microcomputer SysetmsSystems |author=<!--Not stated--> |date=1983 |website=bitsavers |publisher=Intel |access-date=November 30, 2022}}</ref> This included processor boards like iSBC 86/12 and also MMU boards such as the iSBC 309. The first Intel Xenix systems shipped in July 1982.<ref name="dir83"/>{{rp|9}}<ref group="note">Intel also offered their own [[iRMX]] operating system as an alternative for these.</ref> Tandy more than doubled the Xenix installed base when it made TRS-Xenix the default operating system for its [[TRS-80 Model 16]] 68000-based computer in early 1983,<ref name="chin19830207">{{cite news |url=https://books.google.com/books?id=_y8EAAAAMBAJ&pg=PA3 |title=Radio Shack goes to Microsoft's Xenix for Model 16 micros |newspaper=[[InfoWorld]] |date=February 7, 1983 |access-date=January 31, 2015 |author-last=Chin |author-first=Kathy |pages=3}}</ref> and was the largest Unix vendor in 1984.<ref name="bartimo19850311">{{cite news |url=https://books.google.com/books?id=5C4EAAAAMBAJ&pg=PA28 |title=Tandy Revamps Product Line |newspaper=[[InfoWorld]] |date=March 11, 1985 |access-date=January 21, 2015 |author-last=Bartimo |author-first=Jim |pages=28–29}}</ref> [[Seattle Computer Products]] also made (PC-incompatible) 8086 computers bundled with Xenix, like their Gazelle II, which used the [[S-100 bus]] and was available in late 1983 or early 1984.<ref name="dir83"/>{{rp|17}}<ref>{{Citation |title=Gazelle II 16-bit Micro-Computer |url=http://bitsavers.trailing-edge.com/pdf/seattleComputer/brochures/Gazelle_II.pdf |year=1983 |archive-url=https://web.archive.org/web/20220811094327/http://bitsavers.trailing-edge.com/pdf/seattleComputer/brochures/Gazelle_II.pdf |publisher=Seattle Computer Products, Inc. |archive-date=11 Aug 2022 |url-status=live}}</ref> There was also a port for [[IBM System 9000]].<ref>BYTE Guide to the IBM PC, fall 1984, p.61</ref>

SCO had initially worked on its own PDP-11 port of V7, called Dynix,<ref group="note">Unrelated to the later [[Dynix]] from [[Sequent Computer Systems]]</ref> but then struck an agreement with Microsoft for joint development and technology exchange on Xenix in 1982.<ref name="pate-p9">{{cite book harvnb|author-first=Steve D. |author-last=Pate |title=Unix Internals: A Practical Approach |date=1996 |publisherpage=[[Addison9}} Wesley Professional]] |isbn=978-0-201-87721-2 |quote="The Santa Cruz Operation (SCO) was formed in 1979 by Larry and Doug Michels as a technical management consulting business. [...] SCO then changed its focus from consulting to the custom porting of Unix system software and applications. The first version of Unix which SCO developed and sold was called Dynix, a name subsequently used by Sequent. The operating system was based on Seventh Edition Unix and ran on the PDP-11. [...] In 1982, a joint development and technology exchange agreement was reached between SCO and Microsoft bringing together engineers from SCO and Microsoft to further enhance the Xenix operating system which was increasing in popularity. Microsoft and SCO worked together with Logica in the UK and HCR in Canada, producing enhancements to Xenix and porting Xenix to other platforms.|page=9}}"</ref> Microsoft and SCO then further engaged [[Human Computing Resources Corporation]] (HCR) in Canada, and a software products group within [[Logica plc]] in the United Kingdom, as part of making further improvements to Xenix and porting Xenix to other platforms.<ref name="pate-p9"/> In doing so, Microsoft gave HCR and Logica the rights to do Xenix ports and to license Xenix binary distributions in those territories.<ref name="doug-video">{{cite news | url=https://www.santacruztechbeat.com/2016/04/21/watch-doug-michels-sco/ | title=Watch: A look-back conversation with Doug Michels, co-founder of SCO | author-first=Sara | author-last=Isenberg | newspaper=Santa Cruz Tech Beat | date=April 21, 2016}} See around 10:45 mark of interview video.</ref>

In 1984, a port to the 68000-based [[Apple Lisa]] 2 was jointly developed by SCO and Microsoft and it was the first [[shrink-wrapped]] binary product sold by SCO.<ref>{{cite book harvnb|author-first=Steve D. |author-last=Pate |title=Unix Internals: A Practical Approach |date=1996 |publisher=[[Addison Wesley Professional]] |isbn=978-0-201-87721-2 |page=10}} |quote="In 1984 a port of Xenix was made to the Apple Lisa by SCO and Microsoft, and was subsequently sold successfully by SCO as their first binary product, showing the success of the shrink-wrapped market. A port was also made to the Tandy model 16B."}}</ref> The [[Multiplan]] spreadsheet was released for it.<ref>{{cite AV media |title=Photograph of Lisa Xenix Multiplan diskette |medium=Digital photography |language=en |url=https://i.postimg.cc/VLbyqzt9/xenix.png |access-date=24 September 2019 |format=JPEG |publisher=Postimg.com}}</ref>

A generally available port to the ''unmapped'' [[x86|Intel 8086/8088 architecture]] was done by The Santa Cruz Operation around 1983.<ref>{{cite conference |author-first1=John Bruno |author-last1=Hare |author-first2=Thomas Dean |author-last2=Thomas |title=Porting Xenix to the Unmapped 8086 |book-title=Proceedings of the USENIX Winter Conference |publisher=USENIX Association |date=1984 |location=Washington, D.C. }}</ref><ref>{{cite web |title=SCO Company History |publisher=Operating System Documentation Project |url=http://www.operating-system.org/betriebssystem/_english/fa-sco.htm |access-date=May 14, 2008}}</ref><ref>{{cite web |author-last=Barger |author-first=Jorn |author-link=Jorn Barger |title=Timeline of GNU/Linux and Unix |url=http://laurel.datsi.fi.upm.es/~ssoo/IG/download/timeline.html |access-date=May 14, 2008}}</ref> SCO Xenix for the PC XT shipped sometime in 1984 and contained some enhancement from [[4.2BSD]]; it also supported the [[Micnet]] local area networking.<ref>{{cite book harvnb|author-first=Steve D. |author-last=Pate |title=Unix Internals: A Practical Approach |date=1996 |publisher=[[Addison Wesley Professional]] |isbn=978-0-201-87721-2 |page=10}} |quote="In 1983 the PC [XT] emerged. SCO started porting to the 8088 but concentrated on the 8086, producing a release of SCO Xenix in 1984 which ran in 640 Kbytes with a 10 Mbyte hard disk. The release could support three or more users simultaneously, had multiscreen (virtual console) facilities, [[Micnet]] local area networking and enhancements added from 4.2BSD."}}</ref>

While Xenix 2.0 was still based on Version 7 Unix,<ref>{{cite book |first=Ellie |last=Cutler |display-authors=etal |title=SCO Unix in a Nutshell |url=https://archive.org/details/scounixinnutshel00elli |url-access=registration |date=1994 |publisher=[[O'Reilly Media, Inc.]] |isbn=978-1-56592-037-8 |pages=[https://archive.org/details/scounixinnutshel00elli/page/312 312]–}}</ref> version 3.0 was upgraded to a [[Unix System III]] code base,<ref name="dir83"/>{{rp|9}}<ref name="Frisch2002">{{cite book |author-first=Æleen |author-last=Frisch |title=Essential System Administration: Tools and Techniques for Linux and Unix Administration |url=https://archive.org/details/essentialsystema00fris_0 |url-access=registration |date=2002 |publisher=[[O'Reilly Media, Inc.]] |isbn=978-0-596-55049-3 |page=xiii}}</ref><ref name="KentWilliams1990">{{cite book |author-first1=Allen |author-last1=Kent |author-link1=Allen Kent |author-first2=James G. |author-last2=Williams |title=Encyclopedia of Computer Science and Technology |volume=22 - Supplement 7 |chapter=Artificial Intelligence to Vector SPate Model in Information Retrieval |chapter-url=https://books.google.com/books?id=L7NOABDqaMcC&pg=PA404 |date=May 15, 1990 |publisher=[[CRC Press]] |isbn=978-0-8247-2272-2 |pages=404–}}</ref> a 1984 Intel manual for Xenix 286 noted that the Xenix kernel had about 10,000 lines at this time.<ref name="intel"/>{{rp|1–7}} It was followed by a [[Unix System V|System V R2]] codebase in Xenix 5.0 (a.k.a. Xenix System V).<ref name="Lapin1987">{{cite book |author-first=Juraj E. |author-last=Lapin |title=Portable C and Unix System Programming |date=1987 |publisher=[[Pearson Education]] |isbn=978-0-13-686494-3 |page=106 |quote=The Xenix 2.3 version generally resembles V7's [ABI]; the Xenix 3.0 version resembles SIII's, and the Xenix 5.0 version resembles SV2's.}}</ref>

"Microsoft hopes that Xenix will become the preferred choice for software production and exchange", the company stated in 1981.<ref name="greenberg198106">{{Cite magazine |author-last=Greenberg |author-first=Robert B. |date=June 1981 |title=The Unix Operating System and the Xenix Standard Operating Environment |url=https://archive.org/stream/byte-magazine-1981-06/1981_06_BYTE_06-06_Operating_Systems#page/n249/mode/2up |magazine=[[Byte (magazine)|Byte]] |pages=248–264}}</ref> Microsoft referred to its own [[MS-DOS]] as its "single-user, single-tasking operating system",<ref name="byte198207">{{cite news |url=https://archive.org/stream/byte-magazine-1982-07/1982_07_BYTE_07-07_Computers_in_the_Arts_and_Sciences#page/n321/mode/2up |title=Upward Migration / Part 2: A Comparison of CP/M-86 and MS-DOS |newspaper=[[BYTE]] |date=July 1982 |access-date=23 March 2016 |author-last1=Taylor |author-first1=Roger |author-last2=Lemmons |author-first2=Phil |pages=330}}</ref> and advised customers thatwho wanted [[multiuser]] or [[Computer multitasking|multitasking]] support to buy Xenix.<ref name="byte198207"/><ref name="swaine19820823">{{cite news |url=https://books.google.com/books?id=VDAEAAAAMBAJ&pg=PA24 |title=MS-DOS: examining IBM PC's disk-operating system |newspaper=[[InfoWorld]] |date=August 23, 1982 |access-date=January 29, 2015 |author-last=Swaine |author-first=Michael |author-link=Michael Swaine (technical author) |pages=24}}</ref> It planned to over time to improve MS-DOS so it would be almost indistinguishable from single-user Xenix, or '''XEDOS''', which would also run on the 68000, Z8000, and LSI-11; they would be [[upward compatible|upwardly compatible]] with Xenix, which ''[[Byte (magazine)|Byte]]'' in 1983 described as "the multi-user MS-DOS of the future".<ref name="morgan198201">{{cite news |url=https://archive.org/stream/byte-magazine-1982-01/1982_01_BYTE_07-01_The_IBM_Personal_Computer#page/n7/mode/2up |title=Of IBM, Operating Systems, and Rosetta Stones |newspaper=[[Byte (magazine)|Byte]] |date=January 1982 |access-date=October 19, 2013 |author-last=Morgan |author-first=Chris |page=6}}</ref><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 |newspaper=[[BYTE]] |date=October 1983 |access-date=January 30, 2015 |author-last=Fiedler |author-first=Ryan |pages=132}}</ref> Microsoft's Chris Larson described MS-DOS 2.0's Xenix compatibility as "the second most important feature".<ref name="larson198311">{{cite news |url=https://archive.org/stream/byte-magazine-1983-11/1983_11_BYTE_08-11_Inside_the_IBM_PC#page/n291/mode/2up |title=MS-DOS 2.0: An Enhanced 16-Bit Operating System |newspaper=[[BYTE]] |date=November 1983 |access-date=19 March 2016 |author-last=Larson |author-first=Chris |pages=285}}</ref> His company advertised DOS and Xenix together, describing MS-DOS 2.0 (its "single-user OS") as sharing features and [[system call]]s with Xenix ("the multi-user, multi-tasking, Unix-derived operating system"), and promising easy porting between them.<ref name="iw19830627">{{cite news |url=https://books.google.com/books?id=yy8EAAAAMBAJ&pg=PA44 |title=Before you bet your business software on an OS, look who's betting on MS-DOS and Xenix. |newspaper=[[InfoWorld]] |date= June 27, 1983 |access-date= January 31, 2015 |pages=44 |type=advertisement}}</ref>

SCO released its [[SCO Unix]] as a higher-end product, based on System V R3 and offering a number of technical advances over Xenix; Xenix remained in the product line. In the meantime, AT&T and [[Sun Microsystems]] completed the merge of Xenix, BSD, [[SunOS]] and System V R3 into System V R4. The last version of SCO Xenix/386 itself was System V R2.3.4, released in 1991.<ref>{{cite book harvnb|author-first=Steve D. |author-last=Pate |title=Unix Internals: A Practical Approach |date=1996 |publisher=[[Addison Wesley Professional]] |isbn=978-0-201-87721-2 |page=10}}</ref>

Aside from its AT&T Unix base, Xenix incorporated elements from [[Berkeley Software Distribution|BSD]], notably the [[Vi (text editor)|vi]] text editor and its supporting libraries ([[termcap]] and [[curses (programming library)|curses]]).<ref name="ibm"/> Its kernel featured some original extensions by Microsoft, notably [[file locking]] and [[Semaphore (programming)|semaphores]],<ref name="ibm"/><ref name="intel"/>{{rp|1.12}} while to the [[User space|userland]] Microsoft added a "visual shell" for [[Menu (computing)|menu-driven]] operation instead of the traditional [[UNIX shell]].<ref name="ibm"/> A limited form of local networking over serial lines ([[RS-232]] ports) was possible through the "micnet" software, which supported file transfer and [[electronic mail]], although [[UUCP]] was still used for networking via [[modem]]s.<ref name="ibm"/>

Trusted Xenix was a variant initially developed by [[IBM]], under the name Secure XENIX; later versions, under the Trusted Xenix name, were developed by [[Trusted Information Systems]].<ref>{{Citation |author-last1=Gligor |author-first1=Virgil D. |author-last2=Chandersekaran |author-first2=C. Sekar |author-last3=Chapman |author-first3=Robert S. |title=Design and Implementation of Secure Xenix |journal=IEEE Transactions on Software Engineering |volume=SE-13 |issue=2 |pages=208–221 |issn=0098-5589 |date=February 1987 |doi=10.1109/tse.1987.232893|s2cid=15376270 }}</ref> It incorporated the [[Bell-LaPadulaBell–LaPadula model]] of multilevel security, and had a multilevel secure interface for the [[STU-III]] secure communications device (that is, an STU-III connection would be made available only to those applications running at the same privilege level as the key loaded in the STU-III). It was evaluated by [[formal methods]] and achieved a B2 security rating under the [[United States Department of Defense|DoD]]'s [[Trusted Computer System Evaluation Criteria]]—the second highest rating ever achieved by an evaluated operating system.<ref>{{Cite book |author-last=Jaeger |author-first=Trent |title=Operating System Security |publisher=Morgan & Claypool Publishers |series=Synthesis Lectures on Information Security, Privacy, and Trust |date=2008 |url=https://books.google.com/books?id=P4PYPSv8nBMC |isbn=978-1-59829-212-1}}</ref> (examples of A1-class systems are Honeywell's [[SCOMP]], Aesec's [[GEMSOS]], and Boeing's [[SNS Server]]). Version 2.0 was released in January 1991, version 3.0 in April 1992, and version 4.0 in September 1993.<ref>{{cite web |author-last=Lévénez |author-first=Éric |title=UNIX History |website=levenez.com |date=May 1, 2011 |url=http://www.levenez.com/unix/ |access-date=May 18, 2011}}</ref> It was still in use as late as 1995.{{Citation needed|date=May 2024}}

* [http://www.tenox.net/docs/ Xenix documentation and books for Download] {{Webarchive|url=https://web.archive.org/web/20141021101438/http://www.tenox.net/docs/ |date=2014-10-21 }}