[Simh] Simh Digest, Vol 198, Issue 16

[Christian Gauger-Cosgrove]

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.

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). 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).


Best regards,
Christian