Date   : Tue, 07 Jun 1983 18:21:51-EDT
From   : rej@cornell
Subject: 68000 Unix systems

It is hard for me to believe that a 68000 cannot run Unix, because I
have used one that does.  A Callan Unistar-100 with half a meg performs
pretty well with one user.  It is definitely I/O bound, but still a nice
system.  It performs remarkably better than a VAX-11/780 at two in the
afternoon!

The Unistar runs Microsoft's V7 port, "with Berkeley enhancements".
Therefore, it performs swapping, not paging.  It uses the SUN board, so
I think that it has its own bipolar MMU.  As long as there is enough
memory to prevent paging, it performs pretty well.  256K is not enough to
load vi without swapping out csh, but 512K lets compiles and edits take
place in parallel.  A multi-user machine should definitely have even more
memory, although I think that you should probably just get more machines.
More memory would always be a good idea, since the lack of virtual memory
puts a hard limit on the size of programs.

The Unistar has 5 inch winchesters, which are usually not fast.  However, it
only seems to be three or four times slower than an unloaded VAX when doing
C compiles.  I haven't timed it real carefully, so perhaps it is even slower.
However, as I said, a Unistar-100 is definitely faster than a VAX at two in
the afternoon, with a few EMACS, a troff, and a large LISP program in progress.
On a personal computer, the speed of the computer is related only to your
demands on it, not your neighbors.

A Unistar-100 with 10 or 20 Meg disk and 512K is in the $10,000 range.
It probably won't run large LISP program until it has virtual memory, but
it will do most Unix jobs quite nicely.