More mystery recycler boards - DEC, Fujitsu(??), Cipher, Emulex
pete at dunnington.plus.com
Wed Sep 7 09:34:28 CDT 2016
On 07/09/2016 13:02, Noel Chiappa wrote:
>> From: Pete Turnbull
>> all microPDP-11/73 machines had an M8190. The M8192 was mostly sold
>> as an OEM board.
> That's so bizarre (although the "Supermicrosystems Handbook", which
> covers the 11/73, confirms it used the KDJ11-B).
As does the MicroPDP-11 Systems Maintenance Manual, the Micro-PDP-11
Handbook, some Micronotes, the MICRO/PDP-11 Technical Manual, the IPB, ...
> So the KDJ11-A
> (M8192) was not used in any 'PDP-11/xx'?
Unless DEC sold something like a PDP-11/73S in a BA11-S chassis (like a
PDP-11/23plus), it was only used for OEM systems and customer-fitted
> The other thing that makes no sense is that the KDJ11-B (M8190) has
> all that extra circuitry on it to support PMI, etc - all of which is
> unused in the 11/73 application! Why not just plug in a (presumably
> cheaper) M8192? In the /73 application, the two are basically
> equivalent. (OK, there are two built in serial lines on the M8190 -
> big whoop.) Both have 8KB caches (although the one in the M8190 has
> slightly fancier tagging, IIRC), etc, etc. Maybe it's the ROM (which
> the M8190 has, but not the M8192)?
Don't forget the LTC :-) All in all it saves a decent amount of
backplane space, makes field service easier, and follows DEC's attempts
to integrate as much as possible. Otherwise, you'd need an additional
bootstrap card such as an MRV11-D with -B2 boot ROMs, a DLVE1 (DLV11-JE)
for the SLUs, something with an LTC, and termination. That's at least
twice as many slots in a Q-Q backplane and four slots in Q-CD. A BDV11
wouldn't work as it doesn't have the ROM capability (well, one of mine
does but it's been seriously modified, well beyond the ECO for 22-bit
:-)). OK, you could use an MXV11-B with -B2 boot ROMs, but that's an
expensive way unless you just want a very small (and slower) system, and
you might still need termination.
And don't forget that DEC sold the microPDP-11/73 as a lower-cost
alternative to the microPDP-11/83 which didn't appear until slightly
later, or looking at it another way, as a fancier and faster
microPDP-11/23. The very first boards had some ASIC/J-11 problems that
meant they wouldn't work with an FPJ11, and the first J-11 CPUs wouldn't
run nearly as fast as intended so they were fitted with 15MHz crystals
(as-sold-by-DEC 11/83 systems have 18MHz crystals). I couldn't possibly
imply they were finding a way to sell the inferior parts. After that
it's probably all marketing differentiation.
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