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Xenix on a 386

XENIX (the all-upper-case version of the name is the formal one, e.g. in contemporary Microsoft material; Xenix is the form usually used now) was Microsoft's port of AT&T UNIX; it was a portable operating system with ports to various platforms. It was based on v6, v7, SYSIII, and later SYSV.

XENIX was originally developed on a DEC Virtual Address Extension (VAX) running the Virtual Memory System (VMS) and a PDP-11 running UNIX V7, albeit now using Microsoft's own in-house minicomputers, and then converted into assembly language specific to the new 16-bit Motorola 68000 and Intel 8086 microprocessors. This put XENIX at the high end of the microcomputer market, which was still dominated by 8-bit machines, but well below the lowest end of the minicomputer market - "XENIX -- Microsoft Short-lived Love Affair with Unix "

Unfortunately, "Xenix even incorporated the elements of BSD and became the most widely installed base of any Unix variant. Talking about the different modifications of Xenix, it was ported to Zilog Z8001, Intel 8086, Tandy Corporation’s 68000 based computers, and even a variant for Apple Lisa."

Modifications to Western Electric v7 included those necessary to transport the UNIX system from the larger PDP-11 mini computer to the 16-bit microprocessors. Currently scheduled machines included the DEC LSI-11/23, Zilogs Z8001 and Z8002, Intel's 8086 and 286, and Motorola's MC68000. - Robert Greenburg, uSloth.

Because of the price of the OS, about $500USD for the OS, and $500USD for the developer tools, combined with cheap PC and compatibles, Xenix was the most widespread UNIX until the rise of Linux. Xenix due to its inherent multi-user capabilities became widespread in sales environments with POS (Point of Sales) terminals, and for scheduling systems commonly found in hotels and restaurants. Occasionally you can still find this setup still running on aging hardware.

With the rise of the IBM PC, it primarily became an x86 based OS. Xenix eventually became SCO Unix, then later SCO OpenServer, where it still languishes today.



Xenix supported the following platforms:

  • IBM 386 [386 GT] The 32bit ones will run on Qemu/Virtual PC ( Sometimes called 386AT )
  • IBM PS/2 [386 MC] This version was specifically for MCA computers with a 386 or higher CPU. ( Sometimes called 386PS )
  • SCO Announced Xenix for the Model 50(286), 60(286) and 80[Ran 386 MC], but its unknown if there are archives of it.
  • IBM 286 [286] - This version is now easy to find, but hard to run... It does not work on a 386.
  • IBM PC [8088 or x86] - This is 'easy' to find.

This is a list of version numbers for the various Architectures:

  • SysV 386 – 3.2, 4.2
  • 386 – 2.2.3b, 2.3.1, 2.3.2f, 2.3.4a, 2.3.4h ( SCO v2.2.3b, v2.3.2f, v2.3.4h)

*(You Plan to Install TCP/IP (XENIX.386 v2.3.4 only)

  • 286 – 2.1.3*, 2.2.1e, 2.2.3b, 2.3.2b, 2.3.2d ( SC0 v2.1.3, v2.2.1e, v2.2.3b, v2.3.2d)

*(Honey DanBer UUCP package v2.3.2 onward)

  • 8086 – 2.1.3* (SCO v2.1.3)
  • These are currently the only two that boot on pcjs's website.



  • PDP-11 - No versions of this exists online. There is a note that Xenix with Programmers console ran on a PDP-11/34. Xenix on PDP
  • Zilog Z8001 [c 1979] - I have only found sales literature that mentions this.*

* Note: This sounds like vaporware since neither the Onyx 1 nor the Commodore 900 ran Xenix


A quick list of a few software programs that were available on Xenix. I know the x86 platform was the most supported, I now know that some of these made it to the less popular 68000 platform.


Microsoft made several of their programs in the 1980's available on the Xenix platform. Microsoft Multiplan, and the BASIC Compiler.


"the base operating system does not include development tools such as a C compiler, but it does include the linker and, importantly, an assembler (which is needed to rebuild the configuration files). The assembler is, however, disguised to make it less obvious what it is by giving it a different name and that is what I have been trying to remember ever since I saw this post. Finally, this morning, it came to me. You should find that you have something called 'storel' (read it as 's-to-rel' as in 'something that transforms .s files into relocatable (ie .o) files' and the name becomes a little less obscure) on the system - I think that it lives in /bin. but it might be somewhere else such as /etc." (Source: here)


  • Autodesk AutoCAD 10i
  • Microsoft Multiplan (available on the Apple Lisa)
  • Microsoft Word v5.0
  • vi (Not really an application, but more of a torture device. May not be present on the x86 version, so ed will have to be used.)


  • Foxpro



  • SCO Professional
  • SCO Lyrix (available on the Apple Lisa)
  • SCO Integra
  • SCO Manager
  • SCO Multiview

* - SCO in this case refers to the original Santa Cruz Operation, and not the later SCO Group who bought the name and started the SCO/Linux lawsuits.

Getting this to run

The 8086 version of XENIX runs fine in an emulator.

Note: The 286 version of XENIX will only run on a 286 processor or a 286 processor emulator that handles the upper byte of the Global Descriptor byte 7, documented as reserved for use on a iAPX 386, by essentially ignoring it, and letting XENIX use it. A poor programming choice at best. (Now, that we know the publication dates of Intel's documentation (1982), we know they ignored the Intel documentation about the use of the upper byte of the descriptor words.. Details here)

User:Neozeed wrote about how to get it to run under QEMU 0.14.

A repository has a file, that when run, unpacks Qemu 0.14, and has a disk, that boots straight into Xenix 2.3.4/386; the uname -a does confirm both the platform and the version.

Also, there is: Xenix 2.3.4/386Backup

Another directory has the same file from a SCO Mega pack called: SCO Xenix 2.3.4 - preinstalled, run in Windows.

External links





Support Level Supplements for Xenix