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One of the things I've found is emulators that let you run the old code on new hardware. I've got Z80's, PDP11's and VAX systems running the old software without having to buy the old machines and tinker getting parts and chips and repairs. The biggest problem is legal access to the software.
Keeping old hardware running can be a chore and most of the parts can be hard to get...
Ebay is a good source of it at a reasonable price... but collectors are making old geek stuff the Beanie Babies of the 2000's.
Luckily, I've got my Z80 CP/M stuff with all the original software and can run it again on the emulators... as well as on the old Z80 boxes if I can get them started up again.
The Borland folks even put up old versions of Turbo Pascal on their site so you can run the old stuff today.