On 2012-04-03, Dave Angel <d...@davea.name> wrote: > And I worked on a system where the microcode was in ROM, and > there was a "patch board" consisting of lots of diodes and some > EPROMs. The diodes were soldered into place to specfy the > instruction(s) to be patched, and the actual patches were in > the EPROMs, which were reusable. The diodes were the only > thing fast enough to "patch" the ROM, by responding more > quickly than the ROM. This was back when issuing a new ROM was > a very expensive proposition; there were masking charges, so > you couldn't reasonably do low quantities.
I worked on a system where the main interface to the system was poking and peeking numbers at memory addresses. -- Neil Cerutti -- http://mail.python.org/mailman/listinfo/python-list
