[Simh] Simh Digest, Vol 198, Issue 16

[Johnny Billquist]

On 2020-07-10 19:16, Christian Gauger-Cosgrove wrote:
> On Fri, 10 Jul 2020 at 11:56, Tom Perrine <tom.perrine at gmail.com> wrote:
>>
>> Way back in the mid/late 80s we had a machine from ATT/Teradata which was a DB appliance.  It was a standalone rack about the size of an RA81, IIRC.  It claimed to have "single board PDP-11, a PDP-11/84" as the CPU.
>>
>> I had never heard of it before or since.  Was that a typo? Hype? Flat out wrong? Some sort of OEM thing?
>>
> The PDP-11/84, and PDP-11/94 for that matter, are the UNIBUS versions
> of the PDP-11/83 and PDP-11/93.

Correct.

> The processors and memories are the exact same as their QBUS
> equivalent (11/84 uses the KDJ11-B processor of the '83; '94 uses the
> KDJ11-E of the '93; the memories are thus the same MSV11 PMI modules
> as you'd find in an '83 or '93).

Except of course you don't find any memory modules in the 93/94, since 
all memory are on the CPU board.

> What makes them UNIBUS capable is the
> KTJ11 module at the very end of the (very short) Q22/CD backplane
> segment, which converts from Q22+PMI to UNIBUS (it's a hex module; AB
> being UNIBUS, CD+EF being Q22+PMI).

It also contains the Unibus map, and also can take the same boot proms 
you might otherwise find on an M9312.

   Johnny

-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol