[HECnet] Hecnet and DDCMP

[Kevin Reynolds]

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
> >> > >
> >> > >
> >