[TUHS] Research UNIX PDP 11/45

Noel Chiappa jnc at mercury.lcs.mit.edu
Tue Jul 18 08:32:43 AEST 2023

    > From: Henry Bent

    > What was the hardware configuration of the 11/45 that Research used to
    > implement early UNIX? .. I have found numerous references to it being
    > an early production 11/45, and I assume that it had an RK05, but I
    > cannot find any details about things like memory size and other
    > peripherals.

A good source is the Ken+Dennis picture:


and the caption which Dennis wrote for it.

The image is not quite definitive, because there are two machines in that
bank of racks: a PDP-11/20, and a PDP-11/45 (mostly hidden behind the
right-hand Teletype), and it's not possible to say which of the two machines
the various peripherals are attached to.

But it seems to have had two RK03's (and an RK11 somewhere to drive them) and
an RF11 (no idea how many RS11 drives it had at that point),; a TU56 (and a
TC11 somewhere to drive that), and a PC05 (with PC11 controller boards).
(There are pages for all these things here:


which include links to the DEC documentation on them.)

I'm doing more searching, through documents I recall having additional
crumbs; let me go ahead and send this, and there will be a lengthy addendum


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