36bit still in use ?

Rob Doyle radioengr at gmail.com
Sun Nov 30 17:53:48 CST 2014

On 11/28/2014 8:44 AM, Pontus Pihlgren wrote:
> On Fri, Nov 28, 2014 at 04:26:09PM +0100, Jacob Dahl Pind wrote:
>> <qoute>
>> Unfortunately I do not have much details. I was at the Living
>> Computer Museum and talked with RIch Alderson, who used to work at
>>  XKL. And he showed me a newer generation router from XKL, opened
>> up, at LCM. And they use a PDP-10 on a chip, and it was actually
>> running TOPS-20, and I could play around at the EXEC level in
>> there.
>> </quote> >

> The system refered to above is visible next to the TOAD-1 in this video
> clip, arround 30 seconds in.
> https://www.youtube.com/watch?v=We3BEaiz194
> I've know for a while that it's been a 36 bit machine under the hood but
> I was told that it is limited in some way, perhaps not a full pager. It
> would be fun to get some details. (And if you can get one for yourself
> of course).

Given that a PDP-10 only supports a virtual address space of 256 KW, and 
that the XKL-2 reports 256MW of memory (another post), it's got to have 
some kind of a pager.  The KS10 only supported 1 MW of memory,
and the biggest KL-10 only supported 4 MW (I think) of memory.

You can find the "TOAD-1 System Architecture Reference Manual" online. 
It describes the pager in detail.  I doubt that the XKL-2 is much different.

The pager is incompatible with any DEC hardware. It would have to be to
support that much memory.   I wouldn't call it 'limited'.


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