[HECnet] SIMH PDP-10 + Networking?

[Rob Jarratt]

-----Original Message-----
From: owner-hecnet at Update.UU.SE [mailto:owner-hecnet at Update.UU.SE]
On Behalf Of Cory Smelosky
Sent: 23 December 2012 18:17
To: hecnet at Update.UU.SE
Subject: Re: [HECnet] SIMH PDP-10 + Networking?


On 23 Dec 2012, at 13:14, "Rob Jarratt" <robert.jarratt at ntlworld.com>
wrote:



-----Original Message-----
From: owner-hecnet at Update.UU.SE [mailto:owner-
hecnet at Update.UU.SE]
On Behalf Of Paul_Koning at Dell.com
Sent: 23 December 2012 17:08
To: hecnet at Update.UU.SE
Subject: Re: [HECnet] SIMH PDP-10 + Networking?


On Dec 23, 2012, at 12:37 AM, John Wilson wrote:

From: <Paul_Koning at Dell.com>

FWIW, DMC and DMR are the same at the programmer level.

(Except for some trivial differences.)   My notes say the limit on
outstanding TX or RX buffers is 7 for DMC vs. 64 for DMR.   Also,
BSEL3 is a read/write reg that survives master clears on DMC but
gives diag completion status on DMR (which is how INIT.SYS tells them
apart).
And opcode 02 is HALTR on DMR and reserved on DMC.   Is there other
stuff?

I didn't know of those details, or other differences that matter to a
driver.
The way I've seen it done is that a DMC driver (7 buffers max) works
fine
for
DMR, and there wasn't any real reason to do DMR-specific things.

Indeed, I have seen the source for a VMS driver that works for both
DMC and DMR, there appear to be some tiny differences in there that I
don't recall, but they are similar enough to use the same driver.

So, my question still stands: If I add DMC11 to the SIMH KS10
emulation, is there anyone who can help me with getting TOPS-10 to
work with it, or if you know how to get TOPS-20 V4.1 to work with it
that
would be even better.

I can't help with writing drivers, but i'd be willing to help with
testing. I think
the documentation covers this configuration of DMC links.   I'm not the
best
with TOPS-10 or TOPS-20, but i'm learning.


Do you have any links to the relevant documentation?






They are somewhat different at the protocol level -- DMC uses an
older version of DDCMP and has some bugs in that implementation,
especially in the "high speed" (1 Mb/s) version.

Buggy WRT dealing with correct implementations, or buggy even
talking to each other?   Just curious (I have a pair of them around
here
somewhere).

Buggy in the sense of not being 100% compliant to the DDCMP spec as
written.   They talk fine to each other.   If you want to have another
DDCMP implementation talk to them, you have to be aware of those
details.   I
don't
remember them but can find them if needed -- they would be in the
NODVR (software DDCMP) RSTS/E driver sources.

	paul