On 2020-07-10 19:16, Christian Gauger-Cosgrove wrote:
On Fri, 10 Jul 2020 at 11:56, Tom Perrine <tom.perr...@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: b...@softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
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