Re: Old Shit
It's going to be the older the system the easier it is to keep going, just as with aeroplanes and racing cars.
Keeping an old spitfire or Lancaster flying - no problem, something just 10 years later such as the Vulcan - very difficult, 10 years later again such as Concorde - impossible.
Similarly with racing cars, any competent mechanic can keep an F1 car from the the early 20th century to the late 80s going, but after they started replying on bespoke ECUs you need a team of specialists from the originating manufacturer to even get them to start. By 2008 the FIA mandated a standard single ECU used by all F1 teams, but there are custom chassis and engine apps, and even if you know how the TAG-320 works, without access to the thousands of parameters which are loaded in, you aren't going to get very far.