9 May
2012
9 May
'12
10:15 a.m.
Tom Uban wrote:
One note on the PDP-11/03 booting the VAX-11/780, the
PDP-11/03 first loads the microcode
into the VAX-11/780, thereby defining the machine's higher level of operating code,
then
a bootstrap to load from a particular hard disk or tape is run.
On an 11/780, the only microcode loaded by the 11/03 is patches or
diagnostics. The main microcode is in bipolar PROMs. There is only a
very small amount of microcode RAM in an 11/780, not enough to hold the
entire microcode.
The 11/785 uses RAM for the entire microcode, so it works as you described.