13 Mar
2023
13 Mar
'23
2:29 p.m.
On Mar 12, 2023, at 4:03 PM, Johnny Billquist
<bqt(a)softjar.se> wrote:
On 2023-03-12 20:34, Paul Koning wrote:
It seems pretty clear to me that whatever DECNET-8 spoke, it was capable of talking to
non-neighbour nodes
The SPD for DECNET-8 have a section about DECnet in general, where it is clearly stated
that NSP supports communication between non-adjacent nodes.
And looking through the code, I saw suggestions of this as well.
I just went back to the "decnet8.doc" file which is a DECnet for RTS-8 user
manual and internals document. Among other things, it describes the protocol (DDCMP and
NSP).
It's clearly Phase I, not Phase II, and the NSP protocol is different in significant
ways. It may be possible to deal with those differences. For example, Phase I has
"single message" service, which are encoded somewhat like ACK messages but using
flag bits that are reserved in the later NSP. If those aren't actually used by
DECnet/8 applications, that wouldn't need to be a problem.
And yes, there is a "route header". Unlike Phase II, it has node numbers rather
than node names. And I did see mention of it in nsp.pa suggesting that the implementation
has that support.
I don't know much about PDP-8 software, but if someone manages to get that code
running I'll take a stab at PyDECnet support for talking to it.
paul
...
Also it's not clear to me that DECnet-8 was ever actually "finished". I
don't think DEC ever got around to actually selling it, and I've never heard an
example of anyone getting it working.
Someone was doing some work on it, I
don't know how far that has come at this point.
Judging by some on-line documents, DECnet/8 was originally Phase I, and that is entirely
incompatible with later versions. The trouble is that it has a rather different NSP
protocol, so applications can't talk to Phase II or later. It would take an actual
NSP protocol translator to fit the two together.
It may be that there also exist Phase II DECnet/8 bits; if so those could be put onto
HECnet. Presumably they don't request intercept, so any communication to
non-neighbors would require Poor Man's Routing.