S100 was also a widely used industrial bus. My first job out of college (1980s) was writing software for a machine tool where the controller was a custom s100 80186 motherboard and a bunch of ROM and static RAM s100 boards. We used a ton of static RAM (probably 4-6 64k boards, I can't remember exactly) that were battery backed up. You could power cycle the controller and just start back where you left off.