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Ms xenix
MS Xenix
developer Microsoft , SCO
License (s) Proprietary
Current  version 2.3.4 (386), 2.3.2 (286) (1991)
ancestry Unix
↳ UNIX System V
↳ Xenix
Architecture (s) x86 , 68k
Others today SCO OpenServer

Xenix is an operating system developed by Microsoft that is based on Unix. Microsoft did not use the name Unix because only the product was licensed without the naming rights of AT&T . It has been ported to the Apple Lisa , DEC VAX, and Intel 8086 . The major OEM providers included Acer , Tandy and SCO (which also took over the later development).


Microsoft Xenix

Microsoft Xenix was originally an Intel 8086 port from AT&T Unix Version 7 with some BSD extensions. On August 25, 1980, the first version of Xenix OS was released. Soon after, Xenix was available in different versions from manufacturers: Altos, Compaq , SCO and Tandy .

According to Microsoft's plans, Xenix was to become the standard operating system for PCs at the time. Nothing came of this, however, as it required a hard disk (cost around 10,000 DM at that time ) and 256 kByte RAM , but the IBM PCs were only delivered with 32 to 64 kByte RAM.

With the start of OS / 2 development, Microsoft lost interest in Xenix.


version publication Remarks
MS Xenix 1980

First Unix from Microsoft under license from AT&T

MS Xenix 3.0 1983

System III for 286 or 68000

MS Xenix 5.0 1985

System V for 286

OEM versions


IBM marketed in the early days, PC / ix Interactive as Unix - operating system for the PC. From 1985 there was then IBM PC-Xenix 1.0 for the AT computers, which was still based on Xenix System III . The later delivered PC Xenix 2.0 was already a Unix System V .


For the company's own Multibus systems System 86/380 and System 86 / 330A, in addition to iRMX 86, Intel Xenix 3.4 and later 3.5 were also offered.

Santa Cruz operation

Founded in 1979 by Larry and Doug Michels, the company was the most important supplier and also pushed technical development. The SCO Xenix 5.0 presented in 1983 was largely based on AT&T Unix System V Release 0 (SVR0). In 1987 Microsoft acquired 25% of the shares of SCO, in return SCO got all rights to Xenix.


The Sinix for the Intel platform was based on Xenix.


The Tandy 6000 systems were shipped with Tandy Xenix 5 . However, the 4000LX models later used SCO Xenix.

SCO Xenix

In 1983 the first Unix system for computers with Intel processors 8086 and 8088 , which was called SCO Xenix System V , was delivered. In 1985 Santa Cruz Operation ported Xenix to the Intel 80286 (product name: SCO Xenix 286) and in 1987 to the 80386 under the name SCO Xenix-386.

The last version was SCO Xenix 386 Release 2.3.4 from 1991, which was only offered for computers with Intel 386 or higher - also in a variant for microchannel machines. In addition to the Bourne Shell (sh) and C Shell (csh), the Kornshell (ksh) was now also included. The menu-driven visual shell (vsh) was intended for inexperienced users. For the connection to other computers, Micnet could be used via serial lines or UUCP . Ed and vi were available as text editors . The system administrator could use the menu-driven sysadmsh interface, for example, for user administration or data backup . Multiscreen allowed the use of several virtual consoles.

As early as 1989, SCO Unix was presented as a successor product, which was backwards compatible with Xenix and took over the device driver model from Xenix. The later system products OpenDesktop and OpenServer (also the current OpenServer 6), which are based on SCO Unix, also allow the execution of old Xenix programs.


version publication Remarks
XENIX 3.0 Release 1.0 Sep 1983
  • SCO Xenix System III with support for IBM XT
XENIX 3.0 Release 1.1 July 1984
  • SCO Xenix System III with support for IBM XT
Release 2.0 1984
  • Further development of SCO Xenix System V based on UNIX System V
Release 2.1.1 1985
  • Further development of the SCO Xenix 286 for Intel 80286
Release 2.1.3 1986
Release 2.2 1986
  • Porting from AT&T UNIX System V Release 2.2 to i386 , making SCO Xenix System V / 386 the first 32-bit operating system for x86 computers
Release 2.2.1 Feb 1988
Release 2.2.2 May 1988
Release 2.2.3 Late 1988
Release 2.3.0 Feb 1989
  • Based on AT&T UNIX System V Release 2.3
  • Improved hardware support, VGA
  • Support for streams
  • Support for 2 graphics cards
  • Execution of SCO Unix 3.2 COFF binary files
Release 2.3.1 1989
Release 2.3.2 July 1989
  • Improved drivers
  • also as an update (xnx137)
Release 2.3.3 1990
  • Update (xnx296a) - not an official release
Release 2.3.4 April 1991
  • Last published version

Further products

The SCO Xenix product line consisted of:

  • SCO Xenix 286/386 operating system
  • SCO Xenix System V Development System - development environment
  • SCO Xenix System V Text Processing System - word processing
  • SCO Xenix-NET - Microsoft network for Xenix systems
  • SCO TCP / IP - TCP / IP only available for Xenix 386
  • SCO NFS - NFS only available for Xenix 386
  • SCO uniPATH SNA-3270 - mainframe connectivity
  • SCO VP / ix - MS-DOS environment under Xenix 386
  • SCO MultiView - multitasking window environment
  • SCO Office Portfolio Suite - application package consisting of Lyrix, Professional, Integra, Manager
  • SCO FoxBASE + - dBASE -compatible database system
  • SCO Multiplan - Spreadsheet

Development tools supplied by Microsoft:

See also


  • Jean L. Yates: The Business Guide to the Xenix System . Addison-Wesley, 1984, ISBN 0-201-08847-9 , pp. 493 .
  • Sam D. Roberts: UNIX, XENIX & VENIX . Hofacker, Holzkirchen 1985, ISBN 3-88963-064-2 , p. 206 .
  • Lee Paul Clukey: Unix and Demystified Xenix . TAB Books, 1985, ISBN 0-8306-1874-0 , pp. 256 .
  • Martin L. Moore: Working with Xenix System V . Scott, Foresman, Glenview, Ill. 1986, ISBN 0-673-18080-8 .
  • Joanne Woodcock, Michael Halvorson: Xenix at work . Microsoft Press, Redmond, Wash. 1986, ISBN 0-914845-55-1 .
  • Christopher Morgan: Inside XENIX® . HW Sams, Indianapolis, IN 1986, ISBN 0-672-22445-3 .
  • Jürgen Fey: The XENIX operating system . Markt & Technik, 1987, ISBN 3-89090-135-2 , p. 300 .
  • Joanne Woodcock, Andreas Dripke: UNIX - XENIX: An introduction . Microsoft Press, Wiesbaden 1989, ISBN 3-528-04553-1 , pp. 404 .

Web links

Individual evidence

  1. SCO: Milestones in The History of The SCO Group 1979 through 1999. (No longer available online.) Formerly in the original ; accessed on January 30, 2009 .  ( Page no longer available , search in web archives )@1@ 2Template: Dead Link / www.sco.com
  2. http://wdb1.sco.com/kb/tasearch.print?taid=105683
  3. http://wdb1.sco.com/kb/tasearch.print?taid=106026