Computers up until the early 80s had "keys" to flip bits directly in memory, from the hobbyist Altair 8800 and its clones ( see the close up panel image at the

Computers up until the early 80s had "keys" to flip bits directly in memory, from the hobbyist Altair 8800 and its clones ( see the close up panel image at the bottom of http://www.vintage-computer.com/altair8800.shtml http://www.vintage-computer.com/altair8800.shtml ), the DEC PDP series ( http://home.earthlink.net/~n1be/pdp11/PDP11.html http://home.earthlink.net/~n1be/pdp11/PDP11.html ), Data General Nova... And back in ye old times, the legendary Seymour Cray cold-booted the CDC 1604 for the first time directly from the keys on the front panel before any OS or software existed to run on the machine.