North Star Horizon

From: Bill/Carolyn Pechter <>
Date: Sun May 17 03:53:16 1998

> <> PDP11/74,
> <
> <Did DEC ever market these, or were they (all four of them, or
> <whatever) just a last ditch effort to save the PDP-11/70 line?
> No, never marketed. Accoring to some they were built with existing
> parts. It was not persued because it would eclipse the vax and the
> 11/70 design was not emi/rfi complient and would be very difficult to
> make it so. At the time the 16 bit mini market was seen to be getting
> smaller in favor of the 32bit superminis.

Actually they were slightly different. (Different front panel,
cache memory and memory control, different backplane.) They were
pretty much the same old 11/70 cpu with CIS on em. KB11-AD=11/45,11/50
11/55 CPU. KB11-B,C=11/70 CPU, KB11-CM=11/74 CPU. I seem to remember
references to the KB11-E somewhere.

When AT&T needed the last available 11/70's for use in their
operations (SCAMOS, COSMOS etc) they bought every last one DEC could
supply. DEC was buying them up from customers on Vax trade-ins, refurbing
them and selling them to "the Telephone Company" so they could
avoid having to get them redesigned and rereleased with new FCC

DEC split up the remaining internal 11/74's and shipped them to regional
offices to use them as internal use only 11/70 replacements (ours was
the regional sales order processing RSTS/E 7.2 system. We just hoped
it would never die, because we had no spares for the beast beyond the
straight 11/70 spares kit.

> Allison

Does anyone know what the "Unicorn" system was. I hear it was an even
later 11 prototype using the what would later become the VAX 11/780
SBI as it's bus. My friend saw the theory of ops on the memory while
building the earliest 11/780's -- but no one has any references to a
Unicorn being created.

There was also the design of the Bluefish 11/68 follow up to the 11/60
and 11/74 (but that was never built).


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Received on Sun May 17 1998 - 03:53:16 BST

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