Bell Labs wrote and runs Unix internally on the Univac 1100 Series machines.
These range from medium scale (about PDP11/70) to 4-by multiprocessors that
really whip! It is apparently full Unix and runs quite well on top of the
rather crufty Os1100 exec in the same style that Eunice runs on VAX. They
are currently dealing with the lawyers about releasing it but the likelihood
is high that it will be out sometime in the near future. They seem very
pleased with it.