Thanks to a friend and former co-worker, I was able to add a small collection of early Xenix distributions to the PCjs archives recently:
Notably, SCO Xenix 386 v2.2.3b is an original copy of what may be the oldest surviving 386-based PC operating system.
Previously, that honor went to (a reconstructed copy of) SCO Xenix 386 v2.2.3c, as explained in this series of OS/2 Museum posts:
Also see this series of SoylentNews posts:
There were older releases of SCO Xenix 386 (2.2.1 and 2.2.2), and there may also be older non-SCO releases out there, but until they surface, this is all we have.
Apr 2, 2018