Qbus split I&D?

Johnny Billquist bqt at update.uu.se
Tue Mar 17 07:34:31 CDT 2015

On 2015-03-17 01:10, Eric Smith wrote:
> Noel Chiappa wrote:
>> I have this dream of one day having an 11/45, with the Enable and the optional
>> cache.Now that would be a sweeet machine: most of the capability of an 11/70,
>> but a lot less power draw.
> The power draw of the 11/45 and 11/70 is almost the same, with the
> exception of the separate memory box(es), MJ11 core or MK11 MOS, for
> the 11/70. I'd *much* rather have an 11/70 with third-party memory
> than an 11/45 with any amount of third-party enhancements. The PEP70
> was a single-board memory that you could plug into an otherwise unused
> slot in the 11/70 CPU backplane, with a few extra wire-wrapped jumpers
> on the backplane, and plug in the four ribbon cables from the 11/70
> cache modules. The same vendor also offered an HC70 "HyperCache"
> option, which when used in conjunction with the PEP70, made all memory
> operate at cache speed.
> It would probably be difficult or impossible to obtain a PEP70 (with
> or without HC70) at this late date. The 11/70 memory bus (between the
> CPU and memory box) is quite simple, so it should be very easy for
> someone with reasonable hardware expertise to design and build a
> modern memory board for it, comparable to the PEP70.

I have from time to time played with the thought...
An 11/70 with the PEP70/HC70 combo would probably draw the same as an 
11/45. And you'd have a much sweeter machine.


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