or, more succinctly, the fact sharing thread
so i used to work on a nuclear power station that is very very old, and has massive levels of control managed by computers and stuff like that from back when computers were difficult, big, and brand new. those machines and computers still need to be maintained, but the people and companies who made certain parts of the computers no longer make them, right - but the thing is you can’t replace them with new parts without a complete redesign.
so there is this bit of my old employer where they take the silicon chipsets, and strip them back, piece by piece and layer by layer, to map them out, so they can manufacture new ones. they reverse engineer the chips and parts for old computers.
but surely they could just buy some on the market right? well, no - there is no garuantee that these chips and boards are safe, real, and not comprimised. so the only way to replace the older stuff is to literally piece by piece strip it back with acid and x rays to find out how it was made, and then to bit by bit rebuild it.