Category Archives: Xenix

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 | 18 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 | 4 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 | 7 Comments


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

Xenix 286 in a VM

The fixes which were included in VirtualBox 4.0.8 happen to help not only OS/2 1.x but also Xenix. The 386 versions of Xenix 2.3.x (not necessarily older versions!) should install in a VM without trouble, but the 286 versions are … Continue reading

Posted in VirtualBox, Xenix | 8 Comments