Re: @misc. folks talking about Xenix ...
>> "Wasn't Xenix a Microsoft OS?"
> No. Xenix was actually ...
Originally it was sold as "Microsoft Xenix"*. SCO may have done the work but Microsoft paid them to do it. So it was "a Microsoft OS". Later, Microsoft sold it to SCO at which point it became SCO Xenix, was updated to System III as SCO UNIX and then was renamed SCO Open Server.
*Byte October 1983 (the UNIX isuuse) p151 has a Microsoft advert for MS-DOS and Xenix. (p475 has a Microsoft advert for their mouse).