On 09/18/2015 08:45 AM, tony duell wrote:
As far as I know, the VAX11/730 (There is one next to me waiting for me to have
time
to restore it) has the microcode entirely in RAM. Classic PERQs (3 in the next
room) have
The PDP-11 console loads the microcode from disk then mostly just sits there
looking pretty whilst the VAX runs.
The 11/780 has a PDP11 to load the microcode (I think) but the 11/730 makes do
with an
8085. After booting I think that handles the console port still.
-tony
780's had a board of fixed microcode, and then a WCS board
was added in later revisions (and all machines in the field
had to be upgraded) to add some additional code to handle
added instructions used by the OS (at least for VMS, don't
know if BSD used it). The WCS microcode was in a file on
the LSI-11's floppy, and it was called in at a certain point
of the VMS boot sequence. That caused a line to print
during the boot. The typical dot matrix printer console on
the 780 was also connected to/through the LSI-11.
Jon
