The AIX for the PS/2 had a thing called the HFT which allowed you to
switch the VGA head between different virtual screens long before LINUX
came along.
I was using Xenix back on the 286, both on PCs and on an Intel 310
Multibus I system. The IBM Xenix I had on my 286 system (A real honest
to god IBM PC AT)
had the feature Mutliscreen (TM) which supproted nine terminals. This
was in 1984.
Amusingly we moved on to the 386 on a Multibus II system. We had
started with an Intel-done port of Interactive Systems’s (Hi, Heinz!)
product but it turns out Intel couldn’t provide (they claim they lost
it) the source of the Multibus II interfaces to allow us to upgrade to a
newer release so given the generic 386 IS/1 sources, I sat down and
rebuilt all the MB-II specific stuff. I really did like that bus, too
bad it didn’t catch on.
-Ron