28 Oct
2021
28 Oct
'21
2:44 a.m.
The MCB is a phase-3 node. I guess T20 used the same stuff as T10
for the MCB, code is here:
http://pdp-10.trailing-edge.com/decnet_mcb_cusps_703a/index.html
It's RSX "based" so maybe Johnny could make it Phase-4?
On tops10 the problem with the MCB and DDCMP etc was solved with the
"DDP" device that made a line (sync or async) on a ANF10 DN87*
frontend a DDCPM device.
That way a Tops10 monitor that was phase-4 could speak sync/async
to another phase-4 node.
I sent the tapes and disk packs with MRC's 4.x and 5.x tops20
for 2020 to LCM.
The 4.x DECnet over DDCMP DUP/KMC for 2020 has reduced "segment size'
from 576 to 390 or something like that due to limited buffer space.
-p
----- Original Message -----
From: "tommytimesharing"
<tommytimesharing at gmail.com>
To: "hecnet" <hecnet at Update.UU.SE>
Sent: Wednesday, October 27, 2021 8:29:35 PM
Subject: Re: [HECnet] DECnet/Python
I had been wanting to put some DDCMP code back into
later versions of
Tops-20.? I don't believe it exists in 5, 6 or 7.? I'm not sure if it
made it into MRC's version of 5 for the KS and those sources have yet to
be recovered.
A KL class machine communicates with DECnet via the CI, the NI or a DTE,
which is a connection to a DN20.? A DN20 is a PDP-11 running DECnet (I
think it's MCB), but I believe you are limited to Phase III.? The last
time I was in that particular neck of the monitor woods, I believe I saw
that the Phase IV router code would not use a DN20 as a router.? I'm
pretty sure it would hand packets to to any node that the DN20 knew about.
It didn't look like it would be a big deal to remove that restriction to
the DN20, but my recollection was that they never spoke full Phase IV.
So I would need something simulating a 'smart' DN20.? Maybe a brilliant
DN20.
Or I could make the KMC/DUP look like a MASSBUS device, adapt the 4.2
UNIBUS based drivers to use that hardware paradigm and then simulate the
hardware and then graft the 4.2 DDCMP code to be another transport
option for the router.
For some very strange reason, this is my idea of fun.