segmented memory models

[Steve Maddison]

2008/8/5 Brian L. Stuart <blstuart at bellsouth.net>:
>> And AFAIK there is no MMU for the PDP11/20 (the first PDP11
>
> Not as a product.  However, lo these many years ago (neigh
> on to 3 decades), I was shown an object that consisted of
> numerous DEC modules and told that it was one of three MMUs
> that had been built for the 11/20.

Probably doesn't count as a bona fide MMU, but I remember reading
something about an add-on for the 11/20 which did kernel/user memory
protection. IIRC it was called the KS11 and was some kind of special
order option, so there probably weren't that many made. Could it be
that that's what you were shown?

-- 
Steve Maddison
http://www.cosam.org/