27 Mar
2026
27 Mar
'26
12:09 p.m.
The 1800 used the 1130's instruction set but from what I heard the CPU was
faster. (Integer multiply and divide in particular). And it had some other
differences, e.g. index registers were real registers, not the first three
locations of core. Also it had a couple more instructions, and the ability
to make sections of core readonly once initialized -- I believe this was
done with toggle switches rather than under software control. It's been a
while. From what I wrote on ibm1130.org/today, apparently at one time I
believed Mike Ross and Bob Rosenbloom have 1800's
I have never found a copy of MPX either as a distribution card set or disk
image. Would LOVE to have it so we can try it out on the ibm1130 simulator
in simh
Brian