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 >> > > >> > > >