Greetings!
 Mentioning pyDECnet might be a red herring, but that's what I'm using to connect to HECnet so I'm mentioning it. I'm trying to connect to Mark Matlock's RSX11M.COM (Static IP:216.177.191.101) and we are getting some weird errors.
 My pyDECnet circuit line looks like this - modeled after Supratim's circuit config that he sent me last year.:
circuit DDCMP-30-1 DDCMP tcp:60001:rsx11m.com:7728 --t3=15 --cost=9
 On Mark's side he has an RSX11M host as the area router and the connection for me is set up thusly:
MNC SET CIR IP-0-5 MODE DDCMP
MNC SET CIR IP-0-5 TCP HOST 0.0.0.0:0 PORT 7728
NCP SET CIR IP-0-5 STA ON
 The connection isn't working. Mark is seeing errors like this:
02:53:40 Â MLTNET - IP-0-5 Incoming packet size error (1541) from
     76.213.76.105:51354. Abort.
02:53:42 Â MLTNET - IP-0-5 Incoming packet size error (1541) from
     76.213.76.105:34404. Abort.
02:53:44 Â MLTNET - IP-0-5 Incoming packet size error (1541) from
     76.213.76.105:34412. Abort.
 The A17RTR node has what look to be the normal settings. the Segment buffer size is normal for DDCMP.
NCP>tell a17rtr show exe char
Node Volatile Characteristics as of 2-MAR-2026 09:35:20
Executor node = 17.1023 (A17RTR)
Identification          = THEMIS2 - A17RTR - DECnet/Python Area-17 Router at Saginaw, TX (DFW)
Management version      = V4.0.0
Software identification = DECnet/Python V1.1.0
Incoming timer          = 30
Outgoing timer          = 30
NSP version             = V4.0.0
Maximum links           = 4095
Delay factor            = 32
Delay weight            = 3
Inactivity timer        = 300
Retransmit factor       = 5
Routing version         = V2.0.0
Type                    = area
Maximum area            = 63
Area maximum cost       = 128
Area maximum hops       = 16
Segment buffer size     = 576
Does anyone know what causes the packet size to be bigger than normal? The ethernet interface on the pyDECnet host is set to 1500MTU as is my firewall/router.
 Where else can I look? I don't see anything in the pyDECnet documentation that talks about DDCMP packet size. Where else can I look?
Regards,
 John H. Reinhardt
On 2026-03-02 18:42, John H. Reinhardt wrote:
> On 3/2/2026 10:44 AM, Johnny Billquist wrote:
>> Hm. The command "MNC SET CIR IP-0-5 MODE DDCMP" should have given a
>> warning that this has been deprecated. In essence, it does nothing.
>>
>> All links are just multinet links, which is DDCMP, with a small header
>> to just get whole packets when using TCP.
>>
>> Â Johnny
>>
>
> That explains the "MLTNET" in Marks error log. So, if I set up the
> phDECnet circuit as a Multinet one is should work?
Sortof yes, but no.
The errors are because RSX is receiving packets without that multinet
header.
What I meant with the above was this:
.mnc set cir ip-0-3 mode ddcmp
MODE have been deprecated.
Please update any configuration scripts.
.
You should have gotten those errors in RSX when doing the command. But
yes, also, the fact that you set your PyDECnet side to talk DDCMP caused
the errors when receiving packets.
>> On 02/03/2026 17.38, Johnny Billquist wrote:
>>> I don't think I've ever tried that DDCMP mode. I don't even remember
>>> what it does...
>>>
>>> Why are you wanting to use it?
>>>
>>> Â Â Johnny
>>>
>
> Because that's what I was told needed to be done to connect to other
> HECnet nodes? Mark has several set up that way and so does Supratim.
Whoever said that is confused and wrong. Sorry. You need to set up
Multinet links.
Johnny
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt(a)softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
Hi,
Just needing to install stuff to a freshly installed VAXstation that’s on HECnet and don’t have many other options for file transfer at the moment..
Is there a VMS Freeware CD shared anywhere?
thx
jake
Some time ago in 2024, while I was writing the Tops-20 Finger Server,
Johnny and I collaborated on a finger specification for Finger over
DECnet. By 'collaborate', I mean I tried putting something together and
Johnny pointed out the mistakes and things iterated from there. It is
hopefully better than an RFC.
The major difference from the Internet specification is that the
protocol more closely aligns with a record orientated paradigm which is
more appropriate for DECnet applications. It can be told to do
otherwise and stream large buffers, but the default is for the
application to limit messages to line at time of no more than about 100
characters. I don't remember if I ever publicly announced availability,
but it can be found on VENTI2::DECNET-FINGER-SPECIFICATION.TXT for
anonymous NFT.
The Tops-20 Finger server itself was effectively complete enough last
year that I felt it appropriate to write a setup guide. It can be read
as a companion piece to the DECnet specification for more background
information on how to implement the protocol.
Further, and perhaps of more interest, it shows how to set up a network
service on Tops-20 without Operator capability, which makes the server
safer to run. Think of not using Administrator (on Windows), root (on
Ultrix), or SYS:, JACCT or [1,2] (on Tops-10) if you know what those
are. I don't know what the equivalent is on other DEC operating
systems. It can also be found on VENTI2::FNGSRV-SETUP.TXT.TXT for
anonymous NFT.
If there are other DECnet finger clients on HECnet than Johnny's or
mine, I would be delighted to hear about it. It's pretty trivial; you
open a connection to a remote host on object 117 (decimal) and send
either a carriage return, a line feed (which gets you the default full
system listing) or a user name followed by one of those two characters.Â
You then read responses and print them until the connection closes.Â
That's it. That's all.
Maybe a one or two line Python program? I could probably still do a
trivial BLISS Common client, but I don't recall having learned the
DECnet API for VMS. At Marlboro, the little Bliss work that I did was
for Tops-20 and Tops-10 and didn't do DECnet. Supposedly, it would have
been easy enough to run on VMS, but I never had the opportunity.
The only DECnet finger servers that are in full time production that I
am aware of are running on MIM:: and VENTI2::. TOMMYT:: runs it on an
experimental basis, but requires a monitor upgrade and reconfiguration
to do a full installation in order to go into production. I'll do that
later this year, I hope.
As we are preparing our relocation to Oregon, I have shut down my home network almost completely taking down all my HECNET nodes.
I expect them to be back online in May or June
Mike
Version 5.3(297)-5 incorporates additional features, enhancements and
fixes since the minor release of 5.3(277)-5 in 30-Aug-2024. These are as
listed below and can be identified in the source code with the edit
number as the prefix of a comment.
As a courtesy, it is being made available early to users of the HECnet
community prior to the tarball being posted on the Internet. It may be
anonymously NFT'ed from VENTI2::TOMMYT:<OINKY.K20MIT> and related
subdirectories.
The changes are briefly summarized below and are further described in
TOMMYT:<OINKY.K20MIT.DOCUMENTATION>KERMIT-20_V5_3_297-5-ANNOUNCEMENT.TXT.
Rich text is also available in .PDF and Microsoft .DOCX format.
Please email me any issues with FAL transfers off list and I will
investigate.
------------------------------------------------------------------------
[278] Modify DEFINE/SAVE to allow another terminal we've assigned
[279] If doing parity, show count of parity errors in STATUS if non-zero
[280] Catch an edge case of a missed parity substitution for a single
character
[281] When logging, do not issue an error message if not local
[282] Fix no blips when logging packets on a local terminal
[283] Specifically identify and log a time out packet, if logging
[284] PUSH [/CONTINUE /RECREATE /RESET (/KILL)]
[285] Rework capabilities when PUSH'ing
[286] Rework POP logic to handle the arcane case of being detached
[287] /NO-MACROS switch to SHOW (ALL) command
[288] Replace an unrolled LSH/IDPB loop with MOVSLJ.
[289] Fix fast multi-generation delete for server
[290] Move some more constants into CONST .PSECT
[291] Properly handle 30 bit one word global pointer in string error
processing
[292] Fix fast multi-generational delete for all wildcards
[293] Fix reporting for no Control-C capability
[294] Do an SFPTR% on every PMAP% in mapi:.
[295] Manage debugging of 36 bit transfers a little better
[296] Fix directory header which I subtly broke with [193]
[297] If no ^C, mention it on SHOW LINE
Kermit-20-Testing-Battery-5.3(297)-5 Updates
On 11/27/2025 3:45 AM, Terri Kennedy wrote:
> Â Dave says this is the first time he has been in the same
> room as a working 780. Yay! And a big shout out to all of
> the volunteers who have been working to get this system run-
> ning, with work starting all the way back in 2018!
>
Yay Dave! I have had the pleasure of knowing 3 different VAX-11/780 systems. The first was the one we got at Rose-Hulman over the summer of 1980 to supplement our PDP-11/70 and 11/45. I believe the 11/45 might have been traded in as part of the VAX purchase. Things are hazy. The other two were in 1983 when I went to work at DePauw University in Greencastle, IN, just up I-70 from Terre Haute and Rose. There were one each for the academic and administrative sides of the school. I was hired on the administrative side as one of the programmers to convert their BASIC PLUS 2 applications on their PDP-11/70 to VAX BASIC on the VAX-11.
--
John H. Reinhardt
I am pleased to announce that we at LSSM have just gotten our
VAX-11/780 up and running!
Now we have to clean up the debugging and repair mess, clean up the
cabling, arrange for a permanent system disk, etc, then we will declare
it an "operational exhibit". Once that's done, it will be on HECnet
whenever it's up and running.
Of course all are welcome to come to LSSM in person and run the
machine. (feel the rumble in the floor, etc)
-Dave
--
Dave McGuire, AK4HZ
New Kensington, PA
A few additions. Owen and I were working on it most recently; Matt
and Richard are not in town now. But both have put effort into it. A
lot of us have; this poor machine took a lot of work to get going.
You missed its initial troubles just before your first visit. We
picked up the machine that summer of 2017 and it was a MESS. From
memory, I hope I don't miss anything, here are the things we worked on
initially:
It had an FP785 installed; we removed it and installed baffles. (will
an FP785 even work in an 11/780??) We left the first power supply in
place in case we find an FP780 board set.
Three of its four power supplies needed bench work. The fourth was
fine. (We don't know the status of the FP780 power supply yet; we'll
look into that if we ever find an FP780.)
The console PDP-11/03 was missing, I built one from parts.
The backplane covers were missing and there were a few groups of
mashed pins. We straightened those, and found and installed the covers.
There was a UBA, but no Unibus chassis. We put together a BA11-K for
that. (We later found its original Unibus chassis.)
Later after Terri spent DAYS tediously combing out the huge mess of
board revisions (the previous owner kept swapping things around trying
to get it running) she got all that straightened out and then figured
out what WCS version we needed. Mike up at RICM was able to supply a
copy, but their disk imaging system was down so he just sent us the
whole box of disks. We imaged them and sent them back, and I pieced
together what should look like an original distribution 11/780 console disk.
This was a big thing for me personally too. All my life I've been a
"DEC guy"; I've had VAXen at home since I was 20 years old, which was 36
years ago, almost as long as I've had PDP-8s and PDP-11s. My first
"real" industry job was as an admin on a set of VAXen, one of which was
an 11/750. But until last night, I had never been in the same room as a
running 11/780. It hit me deeply and felt really, really good.
And it was fitting for Owen; he was at the console during the first
complete boot, and yesterday was his 65th birthday. A few of us took
him out for tasty Indian food right after that boot.
-Dave
On 11/27/25 04:45, Terri Kennedy wrote:
> On 2025-11-27 02:56, Keith Halewood wrote:
>> Great news. I hope you'll be publishing some pictures (perhaps before,
>> during after) of the restoration on the website?
>
> Â There aren't a lot of pictures (at least I didn't take many).
>
> Â A lot of it was just basic mechanical stuff - fixing a seized
> spindle and decayed drive belt on the floppy drive and then im-
> aging a number of floppies with the console software and a bunch
> of diagnostic discs. Dave did all of that.
>
> Â Then there was an interesting project to come up with outlet
> strips to plug all of the individual component AC power cords
> into, since there wasn't an L21-30R receptacle there at the time
> to plug the single "official" power cord into. This will be ad-
> dressed now that it is a functional exhibit.
>
> Â After reseating some cards, Dave and I were able to use a
> cheat I knew of to get past the console complaints about mis-
> matched hardware and we got the first ">>>" prompt in over a
> decade. At that point, "BOOT DU0" would actually go initialize
> the disk controller and turn on the port select on the drive,
> but not go past that point. At that point, we knew we at least
> had a VAX, although a very sick one.
>
> Â At that point, Dave imaged some other console discs and I
> then edited the contents using RT-11 on another system (the
> LSI-11/03 that controls the VAX runs a very modified version
> of RT-11).
>
> Â Next, there was an assortment of boards which were neither
> compatible with each other, nor with the console microcode.
> I discovered the Museum had nearly a complete 780 board set as
> well as some 785 boards, and spent several days with all of
> the boards and DEC's official "VAX-11/780 & VAX-11/782 Revis-
> ion Control" document to bring the system up to revision 8.B
> which is the newest 780 revision. I then spent a few more
> days weeding out bad boards.
>
> Â At that point, the system went from saying "Help me!" (see
> the first photo) to actually booting to the VMS version banner
> for the first time in many, many years (second photo) but then
> hanging.
>
> Â Dave, Owen, Richard and Matt P (apologies if I missed any-
> one, I'm doing this from memory) then discovered that I'd
> missed a bad board, which caused "console transit done" in-
> terrupts to not be seen by the VAX. This past evening, they
> got the 780 to boot, first NetBSD and then VMS. It is also
> now passing diagnostics.
>
> Â Now the work begins to neaten things up, get it the power
> cabling it wants, and configure the console floppy so that
> it can boot VMS, Ultrix-32 or NetBSD, depending on what sort
> of demo will be given.
>
> Â Dave says this is the first time he has been in the same
> room as a working 780. Yay! And a big shout out to all of
> the volunteers who have been working to get this system run-
> ning, with work starting all the way back in 2018!
>
> Â Th last picture is the inside of the 780 in all of its
> glory. It isn't on in this picture because the air baffles
> need to be in place in front of the cards to keep the CPU
> from overheating and going into thermal shutdown. So this
> picture was "posed" to show the board set, before putting
> all of the air baffles back in place.
>
> _______________________________________________
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> To unsubscribe send an email to hecnet-leave(a)lists.dfupdate.se
--
Dave McGuire, AK4HZ
New Kensington, PA
Hi folks, has anyone here used a Lantronix ETS-series or similar
terminal server for LAT connections to RSX? We're having a strange
problem at LSSM and could use some info.
Thanks,
-Dave
--
Dave McGuire, AK4HZ
New Kensington, PA