3 Feb
2017
3 Feb
'17
8:31 p.m.
On Feb 3, 2017, at 3:25 PM, william degnan
<billdegnan at gmail.com> wrote:
On Fri, Feb 3, 2017 at 2:31 PM, Paul Koning <paulkoning at comcast.net> wrote:
Yes, on bitsavers. But John's comment reminds me that RSTS-11 V4A doesn't
support RL02. (Only RF11, RK11, RP11.) V4B may be different, I don't know.
with.
True. I meant to point out the main difference between RSTS-11 and
RSTS/E. The other difference is that it doesn't require EIS. Both follow
from the fact it was designed for the 11/20.
paul
So you're saying for a system with a MMU but no working EIS (removed for
now) and 64KW RAM (half populated M7891) you're suggesting which OS? I
still have to research the best options, RSX-11M?
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, so an OS that requires an
MMU would typically take advantage of EIS instructions. That's the case in RSTS/E,
for example.
OSs designed for non-MMU systems would also typically assume no EIS, because they were
intended for the entire PDP-11 family including 11/20 and the like.
In other words, if you don't have an EIS that works, you're likely to be limited
to no-MMU systems because those are likely to be the only ones whose authors avoided EIS
instructions.
There may be some mixed cases, an OS where the same basic system can be built for no-MMU
as well as MMU configs. If so, there might be a way to build an MMU=yes, EIS=no config.
Or it may come with EIS=no by default because some of its configs have to handle that and
it's easier to do it consistenly. Possibly RSX is such an OS; I don't know.
paul
On Feb 3, 2017, at 12:00 PM, Noel Chiappa <jnc
at mercury.lcs.mit.edu>
wrote:
From: Paul Koning
Another OS that would run on your machine (as
well as an 11/20) would
be RSTS-11 (V4, or I suppose V3 if you can find that)
I'd love to have an old RSTS-11, is there any variant around?
didn't use the MMU
Huh? He's got an MMU (I think): it's the EIS he's currently struggling