Category Archives: Xenix

IBM XENIX: Two Steps Forward

There are reasons to revisit an old topic. Very old, considering that IBM Xenix 1.0 was released in 1984, well over 30 years ago. To recap, this version of Xenix is unique in that it runs only on 286 processors. It … Continue reading

Posted in 286, IBM, VirtualBox, Xenix | 13 Comments

Tales From the Xenix Crypt

What does Xenix have to do with the Enigma machine? Perhaps surprisingly, there is a clear connection… When reconstructing 386 Xenix 2.2.3, the libmdep.a library proved to be a particularly tough nut to crack. That is because it’s one of … Continue reading

Posted in SCO, Software Hacks, Xenix | 7 Comments

What a Coincidence

Timeline: Mid-1988: SCO 386 Xenix 2.2.3 is released 1996 (probably): Someone dumps the 386 Xenix 2.2.3 disks, but enough sectors are missing that the OS is impossible to install January 3rd, 2013: OS/2 Museum posts about the damaged Xenix dump February … Continue reading

Posted in PC history, Xenix | 1 Comment

Oldest Surviving 386 PC OS?

Four years ago, the Xenix 2.2.3 mystery cropped up (twice). The issue has been revisited and thanks to Michael Casadevall, an enthusiastic reader, came to a happy conclusion: 386 Xenix version 2.2.3 was finalized in late June 1988 (the newest … Continue reading

Posted in 386, Microsoft, SCO, UNIX, Xenix | 21 Comments

IBM XENIX 1.0 Incompatibility Details

Some time ago I wrote about IBM PC XENIX 1.0 and why it won’t work on 386 and later processors. Thanks to a kind reader, I’ve been able to analyze the object files used to link the kernel, and I believe … Continue reading

Posted in 286, 386, Microsoft, Xenix | 19 Comments

IBM XENIX: One Step Forward, One Step Back

A while ago I wrote about why IBM PC XENIX 1.0 can’t work on any CPU other than a 286. But not content to leave well enough alone, I attempted to patch this version of XENIX so that it would … Continue reading

Posted in 286, 386, IBM, VirtualBox, Xenix | 5 Comments

Forward Compatibility, Landmines

Several years ago, after attempting to get a very old 286 version of Xenix running in a VM, I concluded that it was probably incompatible with any 386 and later processor. Recently I revisited this issue and examined the problem … Continue reading

Posted in 286, Intel, Xenix | 29 Comments

The XENIX 2.2.3 Mystery, Continued

After pondering the strange TeleDisk images of SCO XENIX 386 2.2.3 (released in 1988) and not being able to make heads or tails of it, I decided it was time to simply restore the TeleDisk images onto actual floppies and … Continue reading

Posted in PC hardware, Xenix | 17 Comments

The XENIX 386 2.2.3 Mystery

On the Internets, one may find a package labeled as SCO XENIX 386 version 2.2.3 or similar, sometimes mislabeled as version 2.2.2. This is one of the very oldest operating systems designed for 386-based PC compatibles, released around June 1988 … Continue reading

Posted in 386, Xenix | 9 Comments

IBM PC XENIX

In 1984, IBM briefly flirted with XENIX, Microsoft’s variant of UNIX licensed from AT&T.  Around 1983-1984, Microsoft and Intel worked on porting XENIX to the 286 processor; Intel shipped XENIX with a number of its development systems in the mid-1980s. … Continue reading

Posted in IBM, Microsoft, Xenix | 25 Comments