[HECnet] Re: DECnet Phase V on VAX/VMS

On Mar 11, 2022, at 10:40 AM, Trevor Warwick <twarwick(a)gmail.com> wrote: I'm a recent joiner to HECnet, and wondered if anyone else has played around with Phase V software at all ? Obviously HECnet itself is a Phase IV network, but you can connect Phase V VAX endnodes using the Phase IV compatibility mode. All my systems are simulated with simh, and getting an Ethernet connection to work was very straightforward, there's just a bit more local configuration required than with Phase IV. However, I spent quite a few years at DEC working on VAX synchronous device drivers, so I was interested to see whether I could get a WAN connection going. The biggest issue was device support. DECnet-VAX Phase V doesn't support any of the older microcoded interfaces (DMC11, DMV11, KMX11 etc), and the later devices (DSV11, DSB32, DST32, etc) aren't supported by simh. The only intersection is actually the DUP/DPV11, where there was a new VMS driver (SEDRIVER) for Phase V, that replaces the individual protocol-specific drivers that were previously used with these devices. I've spent quite a long time this week dredging stuff out of memory from 30 years ago, and still failing to get a DPV11 link to come up, until I eventually realised that a) there are some significant differences between the DUP and DPV, and b) simh does not support the DPV properly (how is one supposed to know this?) ! So after changing my simulated microVAX into an 8600, and the DPV into a DUP, I've managed to get a DDCMP link to come up between this and a PyDecnet router. There still seem to be some rough edges, as it won't always come up until PyDecnet is bounced, and it's also a bit slow for interactive use, as if there's something that's only working on a retransmission, or timer expiry. Anyway, it's been a fun nostalgia exercise to get this far, I'll probably mess about with it some more. Let me know if you have any questions...