[HECnet] SIMH PDP-10 + Networking?

[Cory Smelosky]

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.



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