[HECnet] Hecnet and DDCMP

[Mark Abene]

I don't recall offhand if the DECnet/E 2.0 tape image floating around
is compatible with RSTS/E v7.   Can anyone else comment?

On Thu, Jan 5, 2012 at 11:15 PM, Kevin Reynolds <tpresence at hotmail.com> wrote:
I have RSTS/E but its v7.

Kevin

Date: Thu, 5 Jan 2012 22:29:01 -0500

Subject: Re: [HECnet] Hecnet and DDCMP
From: phiber at phiber.com
To: hecnet at update.uu.se


Assuming Rob makes his patch to SIMH available, is there anyone on
HECnet willing to test peering with my RSTS/E setup?

On Wed, Jan 4, 2012 at 5:45 PM, Rob Jarratt <robert.jarratt at ntlworld.com>
wrote:
Yes, you are right, I do add a 2-byte length to the start of each buffer
that I send so that the other end can reassemble the buffer. Sorry, I
did
say this in an earlier draft of the email, but decided to leave it out
to
emphasise the simplicity of the implementation.

Regards

Rob

-----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: 04 January 2012 22:15
To: hecnet at Update.UU.SE
Subject: RE: [HECnet] Hecnet and DDCMP

I assume there has to be a bit more to it, because DDCMP is a packet
based
protocol (not a stream protocol as TCP is) and the higher layers rely
on
that.
So there presumably is some form of framing in the emulated data stream
to
indicate where the packet boundaries are.

         paul

-----Original Message-----
From: owner-hecnet at Update.UU.SE [mailto:owner-hecnet at Update.UU.SE]
On Behalf Of Rob Jarratt
Sent: Wednesday, January 04, 2012 5:11 PM
To: hecnet at Update.UU.SE
Subject: RE: [HECnet] Hecnet and DDCMP

All I do in SIMH is to take the data bytes each end wants to send to
the
other
end and send them over a socket, so I don't get involved with DDCMP
itself.
Both ends have to be SIMH for this to work. I don't do anything at the
actual
hardware level, although that would be nice. I think you can get
synchronous
serial cards for the PC but they are quite expensive.

Regards

Rob

-----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: 03 January 2012 21:18
To: hecnet at Update.UU.SE
Subject: RE: [HECnet] Hecnet and DDCMP

DMC-11 speaks DDCMP V3.1 (give or take some bugs in the "high speed"
version).   But that's sync only.   Depending on what you want to talk
to, a
DMC
(or its relatives DMR-11, DMP-11, or DMV-11) may not help; if the
other
end
speaks DDCMP over an async link (UART) then it won't work because the
character framing doesn't match.

That said, I wonder what it means to emulate a DMC-11.   You could
have
it speak DDCMP over a UART, or something else entirely.   If the
former
it
would
talk to another DDCMP node; if the latter it would not but it would
still
work
for tying one emulated DMC-11 to another.

If you want DDCMP, one approach is to get a copy of the spec, and
implement
what it says.   That works; it is how I implemented DDCMP support for
RSTS
V10
(based on an earlier version based on V9.6).   The protocol is quite
simple
and
the spec is well enough written that, if you do what it says, the
result
WILL
interoperate with hardware such as the DMR-11.   The only tricky one
is
the
DMC-11 because it has some undocumented bugs;   the main one I
remember
is that the high speed version can't handle back to back packets.   I
wish
I could
contribute the code   I wrote but I can't, for various reasons one of
them
is that
it's a RSTS device driver and written in 100% assembly language.

It would not be hard to do a version for other platforms; I once
looked at
a
Linux terminal protocol handler (forgot what that is called) that
could
hook
into DECnet/Linux.   Didn't get far enough on that, though.

      paul

-----Original Message-----
From: owner-hecnet at Update.UU.SE [mailto:owner-hecnet at Update.UU.SE]
On Behalf Of Mark Abene
Sent: Sunday, January 01, 2012 6:06 PM
To: hecnet at update.uu.se
Subject: Re: [HECnet] Hecnet and DDCMP

Jarratt, did you make this publicly available on the SIMH list?   It
would
be great
to have a DMC11 device emulated, since I insist on running RSTS/E v8
(for historical reasons... it was the last real RSTS before "the
pollution").
RSTS/E v8
doesn't have ethernet support, so the only way I could have DECnet is
via
a
(previously unemulated)
DMC11 interface.   Does yours work well?

-Mark

On Sun, Jan 1, 2012 at 3:23 AM, Jarratt RMA
<robert.jarratt at ntlworld.com>
wrote:
Working with a friend, I  have written a SIMH emulation of the DMC11
device, so you can do this with SIMH. It tunnels the bytes sent
to/from the device over a socket. We have used the SIMH emulation
to
connect my friend to HECnet over a (simulated) DMC11.

The bit I am not entirely sure about is to what extent this is
using
DDCMP as I don't have a full understanding of DDCMP.

Regards

Rob
On 31 December 2011 18:46, The Presence <tpresence at hotmail.com>
wrote:

Hey guys,

Has anyone worked out a mechanism to connect a node to hecnet
using
DDCMP?
  Perhaps some tunneling technology over IP, or virtualized serial?

Kevin