In the 1980s I worked for a Cobol programmer (Tom wrote accounting software for Wang VS systems, I wrote the user manuals). (Just writing that sentence makes me feel old.) I recall that one of our clients was migrating from an even older system that used wire plug cards. Literally no one knew how they worked; if one wire came out of a card, good luck getting it back in the right place. At least Cobol is more comprehensible than that.
Apparently a company in Texas was still using the IBM 402 in 2012, which works just as you describe. Swappable trays of wired patch panels for programming:
As someone who often cannot repair my own breadboard projects if they come unplugged I understand this all too well. It might have been unfixable as soon as it was out of the builder’s short term memory.
