RL02 version of UNIX6?

Josh Dersch derschjo at gmail.com
Fri Feb 3 15:07:57 CST 2017

On Fri, Feb 3, 2017 at 12:31 PM, Paul Koning <paulkoning at comcast.net> wrote:

> I'm not sure there is one.  DEC OS designers typically would assume that
> they are dealing with non-broken systems.  Systems with MMU all have EIS...

Is this actually true?  I've been working on getting my PDP-11/40 running
recently, and I don't recall anything in the documentation indicating that
an EIS was required if you had an MMU installed.  (On the other hand, the
MMU docs indicate that the Stack Limit Register must be installed if an MMU
is present, though I haven't looked into why this is the case).  For the
record, my system currently has the MMU, but lacks an EIS (still trying to
track one down).  It may be that DEC never shipped an MMU without an EIS in
an 11/40...

- Josh

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