On 1/7/2020 11:46 PM, Thomas Paulsen wrote:

Hell, Linux didn't exist at all till '91.
I think Xenix was more just a casualty of the Unix Wars.  The victors there
were SunOS/Solaris, AIX, and HP-UX.  There were a bunch more walking
wounded that never really achieved much market share.

'In the mid-to-late 1980s, XENIX was the most common UNIX variant, measured according to the number of machines on which it was installed.'
https://en.wikipedia.org/wiki/Xenix

Two other major vendors competing with Xenix were:
1. INTERACTIVE Systems Corp. (ISC) [founded in 1977] with PC/IX, and later IS/3, etc.
2. Santa Cruz Operation (SCO) [founded in 1979] with SCO UNIX, etc.
There were also a number of smaller players in this space.