Reproducing old machines with newer technology (Re: PDP-12 at the RICM)

Jay Jaeger cube1 at
Tue Jul 14 20:06:09 CDT 2015

The 12-bit computer that I "translated" originally had *independent* 1
micro-second clocks in each of four racks.  The processor derived a 3
micro-second clock from that, but also a second clock that was out of
phase with the CPU master clock, used to sync. signals coming in from
the other racks (which had 10 foot cables in between).

On 7/14/2015 7:04 PM, Eric Smith wrote:
> On Tue, Jul 14, 2015 at 3:28 PM, tony duell <ard at> wrote:
>> If you mean 6 different clock sources (i.e. clocks delayed from each other, etc) then that
>> is not typical of a 1970s minicomputer in my experience.
> IIRC, the KB11 processors used in the DEC 11/45 and 11/70 (and other
> related systems) used five "clocks delayed from each other" (more
> commonly known as clock phases). In my experience that was more common
> in 1970s computers than a single-phase clock.

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