A friend exploring the joys of S100 bus computing said there are ways to re-purpose Rasberry Pi GPIO pins to emulate a few old bus technologies.
The airline industry are past masters at mothering old tech in, all those dot matrix printers at the gate have to be driven somehow, the old IBM mainframe links which drove them are being emulated by tn3270 style attachment boxes which can be driven over TCP/IP. (or something)
The software communicates with the card by directly reading and writing to I/O addresses of the card. No modern OS or virtualization would ever allow that. It's why you can't have sound in old MS-DOS games unless you boot DOS or Win9x, or emulate the complete system.
Its flaws are known - since a replacement might be worse, it's often the lesser evil.
E.g. eyetrackers used in psychology studies or tests often still require DOS, because the companies providing these systems don't want to build software that has the same timing capabilities in a newer operating system.
dsign•4h ago