can you run unix on Tandy 1000 SX's?

[Charles Hedrick]

I think the original IBM Unix, probably a Xenix version, ran on XT's.
(I certainly recall seeing it run on a machine here long before there
were 286's, so it had to have.)  Mark Williams software has a V7
derivative that they call Coherent.  I don't know much about it, but I
do know that it runs on the older processors (indeed I think it won't
run on a 286).  The reason Uport won't run on an XT is that it uses
protected mode.  This exists only on the 286 and 386.  It's impossible
to make a real multiprocess OS without using that feature, so Unix is
impossible on an XT.  So, you say, how about the two things I just
listed?  They use sort of smoke and mirrors.  As far as I know, they
work, but any process can walk all over any other's memory if they do
the wrong thing with the pointer registers..  In my opinion, this
means that the processes are not in any normal sense separate
processes.  Since Unix by definition has multiple processes, this
means that they aren't Unix.  But they may look, act, and smell enough
like Unix to be useful.