Maybe this should go to COFF but Adam I fear you are falling into a tap that is easy to fall into - old == unused

One of my favorite stores in the computer restoration community is from 5-10 years ago and the LCM+L in Seatle was restoring their CDC-6000 that they got From Purdue.   Core memory is difficult to get, so they made a card and physical module that could plug into their system that is both electrically and mechanically equivalent using modern semiconductors.   A few weeks later they announced that they had the system running and had built this module. They got approached by the USAF asking if they could get a copy of the design.  Seems, there was still a least one CDC-6600 running a particular critical application somewhere.

This is similar to the PDP-11s and Vaxen that are supposed to be still in the hydroelectric grid [a few years ago the was an ad for an RSX and VMS programmer to go to Canada running in the Boston newspapers - I know someone that did a small amount of consulting on that one].