'Real' is an unfortunate word.
If by 'Real', you mean commercial applications that people pay
money for, then I wasn't aware of the DECnet market being very
large. I'd love to be contradicted on this...
That being said, I can truthfully say that if you are interested
in bullet-proof code, then the best thing you can do is a
port to another transport or platform and perform regression
tests.
I had code that ran on DOS for years that I ported to the protected mode under OS/2 1.3. This was more straightforward than it seems because the Microsoft C version 5 C compiler did just about all of the work and most assembler didn't need to change. Bugs came hurtling out because of edge cases that bumped into segment limits now enforced by hardware. I replaced malloc with direct calls to get exact segments sizes and more bugs showed up. And it was faster than using banked memory, which surprised us.
I'm finishing a transport addition to Kermit to use Tops-10 and
Tops-20 NRT's. Bugs have come flying out because of edge use
cases and recovery and it is now far more robust. This includes
it being a TCP/IP client to C-Kermit.
Same thing with MMAILR (SMTP) over DECnet.
Same thing with FTP over DECnet.
For hobbyist's some DEC OS's never came with a DEC sanctioned
TCP/IP stack. So if you don't have DECnet, you can't
realistically talk to Tops-10 and some others. Probably OS/8, maybe
RSTS and whatever version of RSX you have that Johnny has gotten
to. Others?
Talking to these old operating systems has been a gold mine for finding bugs in Tops-20, supporting CUSPs, Galaxy and DAP. This is nothing against those programmers, they just weren't given the time to fully productize some very interesting features.
I'd prefer to have DECnet in Linux for that reason. However, I
don't recall that I ever came across a very stable version of latd
and the client (whose name I've forgotten). Somebody on this list
worked on them I think.
I like that idea, although I do wonder how many "real" applications would really need, want, or even try to support DECnet directly in these modern times? For the terminal server case that I am initially interested in building, CTERM and a few network diagnostic tools would keep me very satisfied, Adding in some file transfer capabilities would be simply awesome.
It would be really useful even if some of these functions were only exposed through internal PyDECnet sub-commands instead of being available system-wide. I've been happily using PyDECnet for a couple of years, but I haven't yet upgraded to your new test releases, and I haven't kept up on what all is included in your future plans? Regardless, I suspect that any somewhat easier way to keep a version of DECnet running on Linux with even the minimal set of tools would be appreciated by many around here. How do you think the performance would be with CTERM written in Python?
On Tue, Aug 2, 2022 at 10:46 AM Paul Koning <paulkoning@comcast.net> wrote:
> On Aug 2, 2022, at 10:40 AM, Brian Angus <brian.angus@gmail.com> wrote:
>
> Hello,
>
> I'm not a programmer, at least not a very good one, and I'm quite happy to expose my ignorance in the effort to learn something new, so I was wondering how real this dependency is on having Linux kernel support for DECnet. We are quite able to put DECnet packets out on the wire using various user mode processes such as with our favourite emulator SimH. I currently run VAX DECnet on several linux boxes without any special or unusual kernel shenanigans using a simple TAP ethernet driver. I also use other non-IP based protocols such as LAT that do not require any special kernel mode modules, drivers or privileges.
>
> Wouldn't it be awesome if we could install a "simple" DECnet daemon on Linux and tweak the few user mode commands that we still use to point to that instead of the special kernel drivers that are needed today. This is probably just wishful thinking, but a very simple non-kernel DECnet implementation might help ensure its survival for a few more decades.
>
> I could well be completely wrong, but I thought I would ask anyway.
What kernel support gives you is the ability to use the standard "socket" kernel API to communicate using DECnet. User mode code means a different API.
Now if Linux were to add a way to create a user-mode back end to sockets, sort of like a socket analog to FUSE (file system in user mode), then you could do DECnet in user mode and still get sockets.
Hm... SUSE? (Oh well, that acronym is taken...)
paul
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