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Xenix

January 01, 1970

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 SCO OpenServer).

Xenix
Xenix under Bochs
DeveloperMicrosoft, SCO, HCR, Logica
OS familyUnix (SysV)
Working stateHistoric
Source modelClosed source
Initial release1980; 44 years ago (1980)
Latest releaseSystem V Release 2.3.4 / 1991; 33 years ago (1991)
PlatformsPC/XT, x86, PDP-11, Z8001, 68k
Kernel typeMonolithic kernel
Default
user interface		Command-line interface
LicenseProprietary
Succeeded bySCO UNIX, OS/2

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.[1][2] Microsoft chairman Bill Gates said at Unix Expo in 1996 that, for a long time, Microsoft had the highest-volume AT&T Unix license.[3]

History edit

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,[4] purchased a license for Version 7 Unix from AT&T in 1978,[5] and announced on August 25, 1980, that it would make the software available for the 16-bit microcomputer market.[6] Because Microsoft was not able to license the "Unix" name itself,[7] the company gave it an original name.

Microsoft called Xenix "a universal operating environment".[8] It did not sell Xenix directly to end users, but licensed the software to OEMs such as IBM,[9] Intel,[10] Management Systems Development,[11] Tandy, Altos Computer, SCO, and Siemens (SINIX) which then ported it to their own proprietary computer architectures.

 
IBM/Microsoft Xenix 1.00 on 5¼-inch floppy disk

In 1981, Microsoft said the first version of Xenix was "very close to the original Unix version 7 source" on the PDP-11, and later versions were to incorporate its own fixes and improvements. The company stated that it intended to port the operating system to the Zilog Z8000 series, Digital LSI-11, Intel 8086 and 80286, Motorola 68000, and possibly "numerous other processors", and provide Microsoft's "full line of system software products", including BASIC and other languages.[8] The first port was for the Z8001 16-bit processor: the first customer ship was January 1981 for Central Data Corporation of Illinois,[12]: 4  followed in March 1981 by Paradyne Corporation's Z8001 product.[12]: 14  The first 8086 port was for the Altos Computer Systems' non-PC-compatible 8600-series computers (first customer ship date Q1 1982).[note 1][12]: 3 [13][14][15]

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.[16] 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.[12]: 9 [note 2] 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,[17] and was the largest Unix vendor in 1984.[18] 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.[12]: 17 [19] There was also a port for IBM System 9000.[20]

SCO had initially worked on its own PDP-11 port of V7, called Dynix,[note 3] but then struck an agreement with Microsoft for joint development and technology exchange on Xenix in 1982.[21] 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.[21] In doing so, Microsoft gave HCR and Logica the rights to do Xenix ports and to license Xenix binary distributions in those territories.[22]

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.[23] The Multiplan spreadsheet was released for it.[24]

In its 1983 OEM directory, Microsoft said the difficulty in porting to the various 8086 and Z8000-based machines had been the lack of a standardized memory management unit and protection facilities. Hardware manufacturers compensated by designing their own hardware, but the ensuing complexity made it "extremely difficult if not impossible for the very small manufacturer to develop a computer capable of supporting a system such as Xenix from scratch," and "the Xenix kernel must be custom-tailored to each new hardware environment."[12]: Introduction 

A generally available port to the unmapped Intel 8086/8088 architecture was done by The Santa Cruz Operation around 1983.[25][26][27] 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.[28]

The later 286 version of Xenix used the integrated MMU present on this chip, by running in 286 protected mode.[29] The 286 Xenix was accompanied by new hardware from Xenix OEMs. For example, the Sperry PC/IT, an IBM PC AT clone, was advertised as capable of supporting eight simultaneous dumb terminal users under this version.

While Xenix 2.0 was still based on Version 7 Unix,[30] version 3.0 was upgraded to a Unix System III code base,[12]: 9 [31][32] a 1984 Intel manual for Xenix 286 noted that the Xenix kernel had about 10,000 lines at this time.[10]: 1–7  It was followed by a System V R2 codebase in Xenix 5.0 (a.k.a. Xenix System V).[33]

"Microsoft hopes that Xenix will become the preferred choice for software production and exchange", the company stated in 1981.[8] Microsoft referred to its own MS-DOS as its "single-user, single-tasking operating system",[34] and advised customers who wanted multiuser or multitasking support to buy Xenix.[34][35] It planned 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 upwardly compatible with Xenix, which Byte in 1983 described as "the multi-user MS-DOS of the future".[36][37] Microsoft's Chris Larson described MS-DOS 2.0's Xenix compatibility as "the second most important feature".[38] His company advertised DOS and Xenix together, describing MS-DOS 2.0 (its "single-user OS") as sharing features and system calls with Xenix ("the multi-user, multi-tasking, Unix-derived operating system"), and promising easy porting between them.[39]

After the breakup of the Bell System in 1982, AT&T started selling System V.[40] Microsoft, believing that it could not compete with Unix's developer, decided to abandon Xenix. The decision was not immediately transparent, which led to the term vaporware.[41] It agreed with IBM to develop OS/2,[4] and the Xenix team (together with the best MS-DOS developers)[citation needed] was assigned to that project. In 1987, Microsoft transferred ownership of Xenix to SCO in an agreement that left Microsoft owning slightly less than 20% of SCO (this amount prevented both companies from having to disclose the exact amount in the event of an SCO IPO). And SCO would acquire both of the other companies that had Xenix rights,[22] Logica's software products group in 1986 and HCR in 1990.[42][43] When Microsoft eventually lost interest[clarification needed] in OS/2 as well, the company based its further high-end strategy on Windows NT.

In 1987, SCO ported Xenix to the 386 processor, a 32-bit chip, after securing knowledge from Microsoft insiders that Microsoft was no longer developing Xenix.[41] Xenix System V Release 2.3.1 introduced support for i386, SCSI and TCP/IP. SCO's Xenix System V/386 was the first 32-bit operating system available on the market for the x86 CPU architecture.

Microsoft continued to use Xenix internally, submitting a patch to support functionality in Unix to AT&T in 1987, which trickled down to the code base of both Xenix and SCO Unix. Microsoft is said to have used Xenix on Sun workstations and VAX minicomputers extensively within their company as late as 1988.[44] All internal Microsoft email transport was done on Xenix-based 68000 systems until 1995–1996, when the company moved to its own Exchange Server product.[45]

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.[46]

Features edit

Aside from its AT&T Unix base, Xenix incorporated elements from BSD, notably the vi text editor and its supporting libraries (termcap and curses).[9] Its kernel featured some original extensions by Microsoft, notably file locking and semaphores,[9][10]: 1.12  while to the userland Microsoft added a "visual shell" for menu-driven operation instead of the traditional UNIX shell.[9] 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 modems.[9]

OEMs often added further modifications to the Xenix system.[9][10]

Trusted Xenix edit

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.[47] It incorporated the Bell–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 DoD's Trusted Computer System Evaluation Criteria—the second highest rating ever achieved by an evaluated operating system.[48] Version 2.0 was released in January 1991, version 3.0 in April 1992, and version 4.0 in September 1993.[49] It was still in use as late as 1995.

See also edit

Notes edit

  1. ^ The Altos 8086 machines had a custom MMU, which used 4K pages.
  2. ^ Intel also offered their own iRMX operating system as an alternative for these.
  3. ^ Unrelated to the later Dynix from Sequent Computer Systems

References edit

  1. ^ Kelleher, Joanne (1986-02-03). "Corporate Unix: A system struggles to earn its stripes". Computerworld. p. 44.
  2. ^ Leffler, Samuel J.; McKusick, Marshall Kirk; Karels, Michael J.; Quarterman, John S. (October 1989). The Design and Implementation of the 4.3BSD UNIX Operating System. Addison-Wesley. p. 7. ISBN 0-201-06196-1.
  3. ^ . Microsoft. 1996-10-09. Archived from the original on 2001-08-18. Retrieved 2013-09-09.
  4. ^ a b Letwin, Gordon (1995-08-17). "What's happening to OS/2". Newsgroup: comp.os.ms-windows.misc. Usenet: DDFvKo.G4M@lab.lwpi.com. Retrieved 2013-11-06.
  5. ^ Pate, Steve D. (1996). Unix Internals: A Practical Approach. Addison Wesley Professional. ISBN 978-0-201-87721-2. p. 9 "Microsoft licensed Seventh Edition Unix from AT&T in 1978 to produce the Xenix operating system initially for the PDP-11."
  6. ^ "The History of Microsoft - 1980".
  7. ^ . 2010-02-26. Archived from the original on 2013-12-19. In the late 1970s Microsoft licensed Unix source code from AT&T, which at the time was not licensing the name Unix.
  8. ^ a b c Greenberg, Robert B. (June 1981). "The Unix Operating System and the Xenix Standard Operating Environment". Byte. pp. 248–264.
  9. ^ a b c d e f Korn, Philip A.; McAdaragh, John P.; Tondo, Clovis L. (1985). "Expanded personal computing power and capability". IBM Systems Journal. 24 (1): 26–36. doi:10.1147/sj.241.0026.
  10. ^ a b c d Overview of the Xenix 286 Operating System (PDF). Intel Corporation. November 1984. Xenix 286 is Intel's value-added version of the Xenix operating system released by Microsoft Corporation.
  11. ^ "Available Today". BYTE (advertisement). October 1981. p. 380. Retrieved 2016-03-16.
  12. ^ a b c d e f g Microsoft Xenix Operating System OEM Directory, May 1, 1983, Part No. OEM0091B
  13. ^ "Altos Unveils 16-Bit Micros With Unix, 1M-Byte Memory". Computerworld: The Newsweekly of Information Systems Management. Computerworld: 49–50. 1981-11-23. ISSN 0010-4841.
  14. ^ Halamka, John (1983-11-07). "Review: Altos 586". InfoWorld: 89. ISSN 0199-6649.
  15. ^ "Computerworld". Computerworld: The Newsweekly of Information Systems Management. IDG Enterprise: 77–. 1987-10-26. ISSN 0010-4841.
  16. ^ "Introduction to the System 86/360 and System 86/330A Microcomputer Sysetms" (PDF). bitsavers. Intel. 1983. Retrieved 2022-11-30.
  17. ^ Chin, Kathy (1983-02-07). "Radio Shack goes to Microsoft's Xenix for Model 16 micros". InfoWorld. p. 3. Retrieved 2015-01-31.
  18. ^ Bartimo, Jim (1985-03-11). "Tandy Revamps Product Line". InfoWorld. pp. 28–29. Retrieved 2015-01-21.
  19. ^ Gazelle II 16-bit Micro-Computer (PDF), Seattle Computer Products, Inc., 1983, (PDF) from the original on 2022-08-11
  20. ^ BYTE Guide to the IBM PC, fall 1984, p.61
  21. ^ a b Pate 1996, p. 9 "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."
  22. ^ a b Isenberg, Sara (2016-04-21). "Watch: A look-back conversation with Doug Michels, co-founder of SCO". Santa Cruz Tech Beat. See around 10:45 mark of interview video.
  23. ^ Pate 1996, p. 10 "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."
  24. ^ Photograph of Lisa Xenix Multiplan diskette (JPEG) (Digital photography). Postimg.com. Retrieved 2019-09-24.
  25. ^ Hare, John Bruno; Thomas, Thomas Dean (1984). "Porting Xenix to the Unmapped 8086". Proceedings of the USENIX Winter Conference. Washington, D.C.: USENIX Association.
  26. ^ "SCO Company History". Operating System Documentation Project. Retrieved 2008-05-14.
  27. ^ Barger, Jorn. "Timeline of GNU/Linux and Unix". Retrieved 2008-05-14.
  28. ^ Pate 1996, p. 10 "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."
  29. ^ Microsoft Xenix 3.0 ready for 286 January 7, 2014, at the Wayback Machine
  30. ^ Cutler, Ellie; et al. (1994). SCO Unix in a Nutshell. O'Reilly Media, Inc. pp. 312–. ISBN 978-1-56592-037-8.
  31. ^ Frisch, Æleen (2002). Essential System Administration: Tools and Techniques for Linux and Unix Administration. O'Reilly Media, Inc. p. xiii. ISBN 978-0-596-55049-3.
  32. ^ Kent, Allen; Williams, James G. (1990-05-15). "Artificial Intelligence to Vector SPate Model in Information Retrieval". Encyclopedia of Computer Science and Technology. Vol. 22 - Supplement 7. CRC Press. pp. 404–. ISBN 978-0-8247-2272-2.
  33. ^ Lapin, Juraj E. (1987). Portable C and Unix System Programming. Pearson Education. p. 106. ISBN 978-0-13-686494-3. 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.
  34. ^ a b Taylor, Roger; Lemmons, Phil (July 1982). "Upward Migration / Part 2: A Comparison of CP/M-86 and MS-DOS". BYTE. p. 330. Retrieved 2016-03-23.
  35. ^ Swaine, Michael (1982-08-23). "MS-DOS: examining IBM PC's disk-operating system". InfoWorld. p. 24. Retrieved 2015-01-29.
  36. ^ Morgan, Chris (January 1982). "Of IBM, Operating Systems, and Rosetta Stones". Byte. p. 6. Retrieved 2013-10-19.
  37. ^ Fiedler, Ryan (October 1983). "The Unix Tutorial / Part 3: Unix in the Microcomputer Marketplace". BYTE. p. 132. Retrieved 2015-01-30.
  38. ^ Larson, Chris (November 1983). "MS-DOS 2.0: An Enhanced 16-Bit Operating System". BYTE. p. 285. Retrieved 2016-03-19.
  39. ^ "Before you bet your business software on an OS, look who's betting on MS-DOS and Xenix". InfoWorld (advertisement). 1983-06-27. p. 44. Retrieved 2015-01-31.
  40. ^ Shea, Tom (1984-02-20). "New developments may decide battle over Unix". InfoWorld. pp. 43–45. Retrieved 2016-02-25.
  41. ^ a b Flynn, Laurie (1995-04-24). "The Executive Computer". The New York Times. ISSN 0362-4331. Retrieved 2010-04-14.
  42. ^ "Santa Cruz Operation Ltd. to Offer Source for Xenix". InfoWorld. 1986-12-08. p. 33.
  43. ^ "California firm acquires Unix-systems leader". The Ottawa Citizen. Canadian Press. 1990-05-10. p. H8 – via Newspapers.com.
  44. ^ Lambert, Terry (2000-11-07). "Re: Microsoft Source (fwd)". Newsgroup: sol.lists.freebsd.chat. Usenet: 200011062350.QAA25774_usr08.primenet.com@ns.sol.net. Retrieved 2006-10-25.
  45. ^ . Microsoft. Archived from the original on 2005-04-27.
  46. ^ Pate 1996, p. 10
  47. ^ Gligor, Virgil D.; Chandersekaran, C. Sekar; Chapman, Robert S. (February 1987), "Design and Implementation of Secure Xenix", IEEE Transactions on Software Engineering, SE-13 (2): 208–221, doi:10.1109/tse.1987.232893, ISSN 0098-5589, S2CID 15376270
  48. ^ Jaeger, Trent (2008). Operating System Security. Synthesis Lectures on Information Security, Privacy, and Trust. Morgan & Claypool Publishers. ISBN 978-1-59829-212-1.
  49. ^ Lévénez, Éric (2011-05-01). "UNIX History". levenez.com. Retrieved 2011-05-18.

Further reading edit

  • Christian, Kaare (1984-05-29). "A UNIX to be Proud Of". PC Magazine: 165–172. ISSN 0888-8507.; review of the beta SCO Xenix on an XT
  • Twitty, William B. (1984). UNIX on the IBM PC. Prentice Hall. ISBN 978-0-13-939075-3. Covers and compares PC/IX, Xenix and VENIX.
  • Raskin, Robin; Christian, Kaare (August 1986). "Xenix System V: A multiuser answer for the AT?". PC Magazine: 253–266. ISSN 0888-8507.

External links edit

 
Wikimedia Commons has media related to Xenix.

January 01, 1970
xenix, discontinued, version, unix, operating, system, various, microcomputer, platforms, licensed, microsoft, from, corporation, late, 1970s, santa, cruz, operation, later, acquired, exclusive, rights, software, eventually, replaced, with, unix, known, opense. Xenix is a discontinued version of the Unix operating system for various microcomputer platforms licensed by Microsoft from AT amp 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 SCO OpenServer XenixXenix under BochsDeveloperMicrosoft SCO HCR LogicaOS familyUnix SysV Working stateHistoricSource modelClosed sourceInitial release1980 44 years ago 1980 Latest releaseSystem V Release 2 3 4 1991 33 years ago 1991 PlatformsPC XT x86 PDP 11 Z8001 68kKernel typeMonolithic kernelDefaultuser interfaceCommand line interfaceLicenseProprietarySucceeded bySCO UNIX OS 2 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 1 2 Microsoft chairman Bill Gates said at Unix Expo in 1996 that for a long time Microsoft had the highest volume AT amp T Unix license 3 Contents 1 History 2 Features 3 Trusted Xenix 4 See also 5 Notes 6 References 7 Further reading 8 External linksHistory editBell 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 4 purchased a license for Version 7 Unix from AT amp T in 1978 5 and announced on August 25 1980 that it would make the software available for the 16 bit microcomputer market 6 Because Microsoft was not able to license the Unix name itself 7 the company gave it an original name Microsoft called Xenix a universal operating environment 8 It did not sell Xenix directly to end users but licensed the software to OEMs such as IBM 9 Intel 10 Management Systems Development 11 Tandy Altos Computer SCO and Siemens SINIX which then ported it to their own proprietary computer architectures nbsp IBM Microsoft Xenix 1 00 on 5 inch floppy disk In 1981 Microsoft said the first version of Xenix was very close to the original Unix version 7 source on the PDP 11 and later versions were to incorporate its own fixes and improvements The company stated that it intended to port the operating system to the Zilog Z8000 series Digital LSI 11 Intel 8086 and 80286 Motorola 68000 and possibly numerous other processors and provide Microsoft s full line of system software products including BASIC and other languages 8 The first port was for the Z8001 16 bit processor the first customer ship was January 1981 for Central Data Corporation of Illinois 12 4 followed in March 1981 by Paradyne Corporation s Z8001 product 12 14 The first 8086 port was for the Altos Computer Systems non PC compatible 8600 series computers first customer ship date Q1 1982 note 1 12 3 13 14 15 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 16 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 12 9 note 2 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 17 and was the largest Unix vendor in 1984 18 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 12 17 19 There was also a port for IBM System 9000 20 SCO had initially worked on its own PDP 11 port of V7 called Dynix note 3 but then struck an agreement with Microsoft for joint development and technology exchange on Xenix in 1982 21 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 21 In doing so Microsoft gave HCR and Logica the rights to do Xenix ports and to license Xenix binary distributions in those territories 22 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 23 The Multiplan spreadsheet was released for it 24 In its 1983 OEM directory Microsoft said the difficulty in porting to the various 8086 and Z8000 based machines had been the lack of a standardized memory management unit and protection facilities Hardware manufacturers compensated by designing their own hardware but the ensuing complexity made it extremely difficult if not impossible for the very small manufacturer to develop a computer capable of supporting a system such as Xenix from scratch and the Xenix kernel must be custom tailored to each new hardware environment 12 Introduction A generally available port to the unmapped Intel 8086 8088 architecture was done by The Santa Cruz Operation around 1983 25 26 27 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 28 The later 286 version of Xenix used the integrated MMU present on this chip by running in 286 protected mode 29 The 286 Xenix was accompanied by new hardware from Xenix OEMs For example the Sperry PC IT an IBM PC AT clone was advertised as capable of supporting eight simultaneous dumb terminal users under this version While Xenix 2 0 was still based on Version 7 Unix 30 version 3 0 was upgraded to a Unix System III code base 12 9 31 32 a 1984 Intel manual for Xenix 286 noted that the Xenix kernel had about 10 000 lines at this time 10 1 7 It was followed by a System V R2 codebase in Xenix 5 0 a k a Xenix System V 33 Microsoft hopes that Xenix will become the preferred choice for software production and exchange the company stated in 1981 8 Microsoft referred to its own MS DOS as its single user single tasking operating system 34 and advised customers who wanted multiuser or multitasking support to buy Xenix 34 35 It planned 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 upwardly compatible with Xenix which Byte in 1983 described as the multi user MS DOS of the future 36 37 Microsoft s Chris Larson described MS DOS 2 0 s Xenix compatibility as the second most important feature 38 His company advertised DOS and Xenix together describing MS DOS 2 0 its single user OS as sharing features and system calls with Xenix the multi user multi tasking Unix derived operating system and promising easy porting between them 39 After the breakup of the Bell System in 1982 AT amp T started selling System V 40 Microsoft believing that it could not compete with Unix s developer decided to abandon Xenix The decision was not immediately transparent which led to the term vaporware 41 It agreed with IBM to develop OS 2 4 and the Xenix team together with the best MS DOS developers citation needed was assigned to that project In 1987 Microsoft transferred ownership of Xenix to SCO in an agreement that left Microsoft owning slightly less than 20 of SCO this amount prevented both companies from having to disclose the exact amount in the event of an SCO IPO And SCO would acquire both of the other companies that had Xenix rights 22 Logica s software products group in 1986 and HCR in 1990 42 43 When Microsoft eventually lost interest clarification needed in OS 2 as well the company based its further high end strategy on Windows NT In 1987 SCO ported Xenix to the 386 processor a 32 bit chip after securing knowledge from Microsoft insiders that Microsoft was no longer developing Xenix 41 Xenix System V Release 2 3 1 introduced support for i386 SCSI and TCP IP SCO s Xenix System V 386 was the first 32 bit operating system available on the market for the x86 CPU architecture Microsoft continued to use Xenix internally submitting a patch to support functionality in Unix to AT amp T in 1987 which trickled down to the code base of both Xenix and SCO Unix Microsoft is said to have used Xenix on Sun workstations and VAX minicomputers extensively within their company as late as 1988 44 All internal Microsoft email transport was done on Xenix based 68000 systems until 1995 1996 when the company moved to its own Exchange Server product 45 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 amp 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 46 Features editAside from its AT amp T Unix base Xenix incorporated elements from BSD notably the vi text editor and its supporting libraries termcap and curses 9 Its kernel featured some original extensions by Microsoft notably file locking and semaphores 9 10 1 12 while to the userland Microsoft added a visual shell for menu driven operation instead of the traditional UNIX shell 9 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 modems 9 OEMs often added further modifications to the Xenix system 9 10 Trusted Xenix editTrusted 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 47 It incorporated the Bell 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 DoD s Trusted Computer System Evaluation Criteria the second highest rating ever achieved by an evaluated operating system 48 Version 2 0 was released in January 1991 version 3 0 in April 1992 and version 4 0 in September 1993 49 It was still in use as late as 1995 See also editAT amp T 6300 Plus Concurrent DOS PC IX VenixNotes edit The Altos 8086 machines had a custom MMU which used 4K pages Intel also offered their own iRMX operating system as an alternative for these Unrelated to the later Dynix from Sequent Computer SystemsReferences edit Kelleher Joanne 1986 02 03 Corporate Unix A system struggles to earn its stripes Computerworld p 44 Leffler Samuel J McKusick Marshall Kirk Karels Michael J Quarterman John S October 1989 The Design and Implementation of the 4 3BSD UNIX Operating System Addison Wesley p 7 ISBN 0 201 06196 1 UNIX Expo Remarks by Bill Gates Microsoft 1996 10 09 Archived from the original on 2001 08 18 Retrieved 2013 09 09 a b Letwin Gordon 1995 08 17 What s happening to OS 2 Newsgroup comp os ms windows misc Usenet DDFvKo G4M lab lwpi com Retrieved 2013 11 06 Pate Steve D 1996 Unix Internals A Practical Approach Addison Wesley Professional ISBN 978 0 201 87721 2 p 9 Microsoft licensed Seventh Edition Unix from AT amp T in 1978 to produce the Xenix operating system initially for the PDP 11 The History of Microsoft 1980 Xenix variant information 2010 02 26 Archived from the original on 2013 12 19 In the late 1970s Microsoft licensed Unix source code from AT amp T which at the time was not licensing the name Unix a b c Greenberg Robert B June 1981 The Unix Operating System and the Xenix Standard Operating Environment Byte pp 248 264 a b c d e f Korn Philip A McAdaragh John P Tondo Clovis L 1985 Expanded personal computing power and capability IBM Systems Journal 24 1 26 36 doi 10 1147 sj 241 0026 a b c d Overview of the Xenix 286 Operating System PDF Intel Corporation November 1984 Xenix 286 is Intel s value added version of the Xenix operating system released by Microsoft Corporation Available Today BYTE advertisement October 1981 p 380 Retrieved 2016 03 16 a b c d e f g Microsoft Xenix Operating System OEM Directory May 1 1983 Part No OEM0091B Altos Unveils 16 Bit Micros With Unix 1M Byte Memory Computerworld The Newsweekly of Information Systems Management Computerworld 49 50 1981 11 23 ISSN 0010 4841 Halamka John 1983 11 07 Review Altos 586 InfoWorld 89 ISSN 0199 6649 Computerworld Computerworld The Newsweekly of Information Systems Management IDG Enterprise 77 1987 10 26 ISSN 0010 4841 Introduction to the System 86 360 and System 86 330A Microcomputer Sysetms PDF bitsavers Intel 1983 Retrieved 2022 11 30 Chin Kathy 1983 02 07 Radio Shack goes to Microsoft s Xenix for Model 16 micros InfoWorld p 3 Retrieved 2015 01 31 Bartimo Jim 1985 03 11 Tandy Revamps Product Line InfoWorld pp 28 29 Retrieved 2015 01 21 Gazelle II 16 bit Micro Computer PDF Seattle Computer Products Inc 1983 archived PDF from the original on 2022 08 11 BYTE Guide to the IBM PC fall 1984 p 61 a b Pate 1996 p 9 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 a b Isenberg Sara 2016 04 21 Watch A look back conversation with Doug Michels co founder of SCO Santa Cruz Tech Beat See around 10 45 mark of interview video Pate 1996 p 10 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 Photograph of Lisa Xenix Multiplan diskette JPEG Digital photography Postimg com Retrieved 2019 09 24 Hare John Bruno Thomas Thomas Dean 1984 Porting Xenix to the Unmapped 8086 Proceedings of the USENIX Winter Conference Washington D C USENIX Association SCO Company History Operating System Documentation Project Retrieved 2008 05 14 Barger Jorn Timeline of GNU Linux and Unix Retrieved 2008 05 14 Pate 1996 p 10 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 Microsoft Xenix 3 0 ready for 286 Archived January 7 2014 at the Wayback Machine Cutler Ellie et al 1994 SCO Unix in a Nutshell O Reilly Media Inc pp 312 ISBN 978 1 56592 037 8 Frisch AEleen 2002 Essential System Administration Tools and Techniques for Linux and Unix Administration O Reilly Media Inc p xiii ISBN 978 0 596 55049 3 Kent Allen Williams James G 1990 05 15 Artificial Intelligence to Vector SPate Model in Information Retrieval Encyclopedia of Computer Science and Technology Vol 22 Supplement 7 CRC Press pp 404 ISBN 978 0 8247 2272 2 Lapin Juraj E 1987 Portable C and Unix System Programming Pearson Education p 106 ISBN 978 0 13 686494 3 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 a b Taylor Roger Lemmons Phil July 1982 Upward Migration Part 2 A Comparison of CP M 86 and MS DOS BYTE p 330 Retrieved 2016 03 23 Swaine Michael 1982 08 23 MS DOS examining IBM PC s disk operating system InfoWorld p 24 Retrieved 2015 01 29 Morgan Chris January 1982 Of IBM Operating Systems and Rosetta Stones Byte p 6 Retrieved 2013 10 19 Fiedler Ryan October 1983 The Unix Tutorial Part 3 Unix in the Microcomputer Marketplace BYTE p 132 Retrieved 2015 01 30 Larson Chris November 1983 MS DOS 2 0 An Enhanced 16 Bit Operating System BYTE p 285 Retrieved 2016 03 19 Before you bet your business software on an OS look who s betting on MS DOS and Xenix InfoWorld advertisement 1983 06 27 p 44 Retrieved 2015 01 31 Shea Tom 1984 02 20 New developments may decide battle over Unix InfoWorld pp 43 45 Retrieved 2016 02 25 a b Flynn Laurie 1995 04 24 The Executive Computer The New York Times ISSN 0362 4331 Retrieved 2010 04 14 Santa Cruz Operation Ltd to Offer Source for Xenix InfoWorld 1986 12 08 p 33 California firm acquires Unix systems leader The Ottawa Citizen Canadian Press 1990 05 10 p H8 via Newspapers com Lambert Terry 2000 11 07 Re Microsoft Source fwd Newsgroup sol lists freebsd chat Usenet 200011062350 QAA25774 usr08 primenet com ns sol net Retrieved 2006 10 25 Microsoft s Migration to Microsoft Exchange Server The Evolution of Messaging within Microsoft Corporation Microsoft Archived from the original on 2005 04 27 Pate 1996 p 10 Gligor Virgil D Chandersekaran C Sekar Chapman Robert S February 1987 Design and Implementation of Secure Xenix IEEE Transactions on Software Engineering SE 13 2 208 221 doi 10 1109 tse 1987 232893 ISSN 0098 5589 S2CID 15376270 Jaeger Trent 2008 Operating System Security Synthesis Lectures on Information Security Privacy and Trust Morgan amp Claypool Publishers ISBN 978 1 59829 212 1 Levenez Eric 2011 05 01 UNIX History levenez com Retrieved 2011 05 18 Further reading editChristian Kaare 1984 05 29 A UNIX to be Proud Of PC Magazine 165 172 ISSN 0888 8507 review of the beta SCO Xenix on an XT Twitty William B 1984 UNIX on the IBM PC Prentice Hall ISBN 978 0 13 939075 3 Covers and compares PC IX Xenix and VENIX Raskin Robin Christian Kaare August 1986 Xenix System V A multiuser answer for the AT PC Magazine 253 266 ISSN 0888 8507 External links edit nbsp Wikimedia Commons has media related to Xenix SCO Xenix Archived from the original on 2010 01 23 Retrieved 2005 10 25 Xenix timeline Xenix documentation and books for Download Archived 2014 10 21 at the Wayback Machine Xenix man pages Unsorted Xenix images scans and photos at the Wayback Machine archived 3 September 2013 Intel Multibus System 320 for Xenix or iRMX86 Welcome to comp unix xenix sco v1 64 A conversation with Doug Michels co founder of SCO on YouTube https groups google com d msg comp sys tandy UbeLIMssHsE 9isYZrRW LgJ Retrieved from https en wikipedia org w index php title Xenix amp oldid 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