Early 80's. Second to last generation of machines that started with the B1700 in the early 70's 24, rotary switch, and row of paddles. B1700 -> B1800 -> B1900 (B1000) It's cool because there wasn't a single macroinstruction set. The operating system and every language had its own pagable microcode. Was saying on nerdnite last monday that Burroughs managed to come up with some really interesting architectures for a really boring segment of the computer industry (banking)