The whole line of
20 years of IBM muscle computers is basically gone. The same is true
for the Burroughs and Univac machines of the same era.
It is MUCH worse for Burroughs and Univac. IBM was sold in such high numbers
that the probability of some surviving was higher. Both Burroughs and Univac
had an active "scorched earth" policies for systems in the field to keep
them out of the hands of resellers. I don't know of any Burroughs 5xxx/6xxx
systems or Univac 1100's that still exist.
John's Univac III is about the biggest old Univac system that I know of.
There is also a disproportionate number of large scientific computers that
have survived vs business systems. There much fewer in CHM's collection.