>Pete Turnbull wrote:
> Then I'm sure that your ROMs must have been changed at some point in
> the past. The 11/73 never had the same boot ROMs as an 11/83 unless it
> was upgraded (which was quite common).
Jerome Fine replies:
I agree!
> > So the dialogue for the PDP-11/73 and the PDP-11/83 can
> > be identical - it just depends on which version of the
> > EPROMs is being used.
> Of course. The dialogue is in the ROMs, after all, and people did
> upgrade them (to get the ability to boot newer devices, for example).
And DEC did as well, as far as I know since the upgrade
looks like an official DEC job.
However, the J11 chip was left at ver 04 since the crystal
was still only 15 MHz. And without the FPU, it could not
cause a problem.
> > All this discussion seems to point out that the PDP-11/73,
> > PDP-11/83 and PDP-11/93 boards were not identical
> I disagree -- I don't see anything to differentiate an 11/73 board from
> an 11/83 from an 11/84, except the clock and the boot ROMs. Sure,
> different revs of J11 were used. The original spec was for a 20MHz or
> 25MHz chip but it didn't meet the spec. Sure, there were FCOs and
> ECOs, but they applied to both 11/73 and 11/83 (and presumably 11/84).
> You've shown yourself exactly what I said, that if you use PMI memory,
> the system thinks it's an 11/83 and if you use non-PMI memory, it's an
> 11/73.
I failed to make my point so that it could be understood.
I was trying to say that within each board specification
(i.e. all PDP-11/73 quad boards as one of the 3 groups),
there were still variations. There were probably many
variations for the PDP-11/73 or the M8190-AB board
over the years while the boards in the PDP-11/93 group
might have had just a few. But, just saying an M8190-AB
is not sufficient to be able to determine exactly what was
present.
And that is quite a separate issue from whether or not
PMI memory was or was not used with the M8190-AB
or the M8190-AE boards. RT-11 would report both
of these boards as a PDP-11/73B Processor when the PMI
memory (or regular memory) was installed below the CPU.
If the PMI memory was installed above the CPU, RT-11
reported both boards as a PDP-11/83 Processor.
> > nor did they use the same J11 CPU chip all the time, although
> > the last 09 rev CPU chip that was used with the PDP-11/93
> > would probably work with all of the others, just NOT the
> > other way around with the early 04 rev CPU chips.
> Agreed.
I am almost positive we both agree on everything, just
that we sometimes get stuck when we define what we
mean - or at least I am sure I do!
However, perhaps there is one area where we each
tend to have our preference. Since I am an RT-11
software addict, I don't really care what hardware
is being used. In fact, the faster the better in most cases.
Some people like to hear the original fans turning and
are not comfortable with a system that runs 100 times
as fast as the original hardware.
Any finally, I just don't have your knowledge or ability
with fixing hardware. As such, the only thing I am able
to do is swap a board when the hardware does not work.
It would be great if everyone was able to fix a power
supply, but I have 2 BAD BA123 power supplies
that no one wants. This latter is a lament, DEFINITELY
NOT a criticism. I VERY MUCH ADMIRE
your ability to fix hardware!!!!!!!!!!!!!!!!!!!!!!!!!
Sincerely yours,
Jerome Fine
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Received on Sun Dec 14 2003 - 20:35:00 GMT