I'm not convinced that it is a Datamaster. The screen is too small, and the
screen bezel the wrong shape; the trim is the wrong colour (ok, maybe it's
a BW
photo, but the trim on a System/23 isn't usually
that dark that I know of).
And, as I said, System/23 is 5322, not 5051 or any of the other model numbers
we've been seeing here :-)
Well, the model number at the first URL (Thanks Reuben) is 5120 - so which is
correct?
I agree that the "5051" looks very like a "5120" - far more than it
looks
like a
Datamaster.
So perhaps it is a 5110 derivative...
Philip.
I think Philip is right, look at item number 65 (IBM) it list as a 5110-3
http://www.davinsystems.com/pcmuseum/antiques.htm
Reuben