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 most PDP-11s, the
microcode
is stored in ROMs or is hard wired.
--tom
On 5/9/12 12:08 AM, Ethan Dicks wrote:
On Tue, May 8, 2012 at 11:27 PM, B Degnan <billdeg
at degnanco.com> wrote:
You wrote:
"Mike Ross' exhibit consisted of a PDP 11/05 used to interface with
a PDP 15, in two racks. He demonstrated restoration techniques for
attendees. I am not sure exactly what you call this console, there is
no "PDP 15" on the panel, but I assume it's some kind of I/O device
that complements the (not pictured) PDP 11/05 used to presumably
bootstrap this thing."
That _is_ the PDP-15 front panel - if you look, there are 18 data bits.
The PDP-15 CPU was the large spread of M-series cards on the
backplane above this front panel. Its memory was in a black box below
(and not there for much of the weekend). The PDP-11/05 is self-contained
and does the same job as the PDP-11/03 in a VAX-11/780 or the PDP-11
in various models of PDP-10. In each case, the PDP-11 boots from its
own ROMs to start up enough code to feed the larger processor. In the
case of the VAX-11/780, the PDP-11/03 has one RX01 floppy drive. I
don't know what this PDP-11 uses, but there must be some local mass
storage that's part of the scheme.
Many I/O devices of the day did have blinkenlights indicators (usually installed
at the top of the rack), but not this many control switches.
-ethan