>Henk Gooijen wrote:
-----Oorspronkelijk bericht----- From: jwsmobile Sent: Friday, June
03, 2016 7:51 PM To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: PDP-11/94-E
On 6/3/2016 9:11 AM, Jerome H. Fine wrote:
>Rod Smallwood wrote:
>On 03/06/2016 16:43, Jerome H. Fine wrote:
<snip>
Hi its a KDJ11-B all memory on CPU board
Rod
I am very confused. Is your mention of memory on the CPU board
for the PDP-11/83 or the PDP-11/93? I thought that the PDP-11/83
never had memory on the CPU board (assuming that the cache is not
regarded as memory).
This aspect of the thread is probably no longer relevant, I just wanted
to note that PMI memory can be used with what most individuals would
consider to be a PDP-11/73 (naturally a quad) board and the PMI
aspect of the memory will be activated when the PMI memory is
installed ABOVE the CPU board.
Also when PMI memory is installed BELOW the backplane, it is then
used as normal Qbus memory in a Qbus system. I can't see anyone
doing that, but it is allowed.
Jerome Fine
I suspect it is using this board.
M7554-02-KDJ11-DB-WITH-1-5MB-MEMORY-ON-BOARD-USED
http://www.ebay.com/itm/161791207076
I am guessing the 1.5mb isn't cache, but is system memory on this board.
There is also the KDJ11-BF which has no memory on board. M8190-AE.
thanks
Jim
----
Nope, the M7554 is the PDP-11/53 CPU.
The 11/83 had its memory on the bus (either left or right of the module).
The 11/94 did NOT have memory on the bus, because *all* memory is
on the CPU module itself. Note that there are two versions of the 11/94.
One with 2 MB RAM and one with 4 MB RAM (all that can be addressed!).
The 2 MB version and the 4 MB version are identical, just half the RAM
chip
population is not placed. However, all through-hole pins are soldered so
the upgrade from 2 MB to 4 MB would be a real PITA, *if* you'd try it
at all!
- Henk
Thank you for the clarification. I knew that the PDP-11/53 held on board
memory, but I just could not remember that the last two digits were "53".
One other minor clarification that probably most remember, but maybe a few
individuals don't. The CPU boards for both the PDP-11/83 and the PDP-11/93
are almost always used in Qbus only systems. In very rare situations, a
Qnivertor
may also be present to support using the system with Unibus hardware,
but that
situation would be unusual.
The PDP-11/84 and PDP-11/94 use the identical CPU boards, but are
configured to include a Qnivertor (as Rod Smallwood mentions in another
post) and would rarely include any Qbus boards. In addition, for the
PDP-11/84, the PMI memory is different from the memory used in the
PDP-11/83 and there are probably no free Qbus slots for any additional
Qbus boards. For the PDP-11/94, there seems to be a couple of free slots
still available, but since they are not normal Qbus slots (they are
specifically
designed for the PMI memory used in the PDP-11/84 after all), standard
Qbus boards may not work correctly.
I just wanted to mention those aspects for PDP-11/83, PDP-11/93,
PDP-11/84 and PDP-11/94 users.
Please mention if I have made any mistakes in my description.
Jerome Fine
