On Dec 14, 17:47, Jerome H. Fine wrote:
> >Pete Turnbull wrote:
>
> > No, not true. There are both dual and quad 11/73 (the quad being
an
> > 11/73-plus). The 11/73 was 15MHz, the 11/83 was always sold as
18MHz.
>
> Jerome Fine replies:
>
> While I have heard of a PDP-11/23 PLUS, I don't think
> that "PLUS" was ever applied to the PDP-11/73 boards.
I doubt it was an official designation, it's just what we (CFM) called
them if they were in BA11-N boxes. The microPDP-11/73 machines in BA23
boxes always used the quad board, or course, so we never needed to
distinguish.
> >From what I understand, for the PDP-11/23 boards, the
> "PLUS" could mean either the ability to address all 4 MBytes
> of memory with the dual M8186 boards (I understand that
> the original M8186 boards were able to address only 256
> KBytes) or that the quad M8189 board was being used.
"plus" specifically meant the quad board, with the on-board boot ROMs,
LTC and SLUs. All but the very first of revision of the dual boards
can also address 4MB.
> As for the PDP-11/73 boards, I had heard that some
> did have the 18 Mhz crystal, but that might also have
> been done privately. Megan Gentry just mentioned
> that she changed the crystal on her PDP-11/83 board
> to 20 MHz and it ran correctly.
As far as I know, all the ones sold as 11/83 were 18MHz, all the ones
sold as 11/73 were 15MHz.
> > So does the 11/73, though it's different.
>
> This answer was with respect to the boot ROMs. I have
> both a KDJ11-BB (M8190-AB) and a KDJ11-BF
> (M8190-AE). Aside from the 15 MHz vs the 18 MHz
> crystal, the fact that the latter also had the FPU chip
> was standard with the KDJ11-BF. But the rev number
> of the J11 chip on the KDJ11-AB is 04 and the EPROMs
> are version 395E5 / 396E5 which can also be the EPROMs
> for the KDJ11-BF. However, I understand that the J11
> rev number when an 18 MHz crystal is being used must
> be at least 08 and maybe 09.
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).
> 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).
> 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.
> 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.
--
Pete Peter Turnbull
Network Manager
University of York
Received on Sun Dec 14 2003 - 19:09:24 GMT