[retrac]

Boot ROMs for the early PDP-11s could be pretty nifty in their own right though. This is the first version of I believe the RX01 floppy disk boot code. 32 sixteen-bit words: https://www.cca.org/blog/20120222-Diode-Matrix.shtml User-editable!

By the time of the PDP-11/34 things were much more integrated though. Mask IC ROMs. The front panel/interactive serial debugger were actually controlled by an Intel 8008 microprocessor. You needed a computer just to boot the computer even then.