How were 32-bit minis built in the 70s/80?

[Dennis Boone]

 > Prime used 74181 chips for some of their CPUs.  I have a 150 CPU
 > board (1980, though it was likely a relatively minor rehash of an
 > older board), for example.

To extend this comment, I found 74S181 chips in the schematics for
Prime's first machines, the P100/P200/P300, with dates of 1972-73.

De