DECnet Isn't Dead

Ronald Dumsfeld writes "The odds of folks under the age of 25 on Slashdot having heard of DECnet are pretty slim. This article over at Datamation gives some insight into people who've not given up on it. Poke around and find the documentation for the OSI-compliant version, or download the Linux version of the older DECnet IV and bask in the Security Through Obscurity."

Comments

The implementation must be licensed.

[CyricZ]

The OpenVMS implementation of TCP/IP and DECnet must be licensed seperately from the operating system. That is what they mean. The OpenVMS TCP/IP implementation costs less than the OpenVMS DECnet implementation.

Re:TCP/IP license fees?

[UseTheSource]

The specification, yes... The implementation, no. Last I worked on VMS, there was no "built in" TCP/IP stack. This had to be added on after the fact, usually in the form of a closed-source, proprietary implementation. (i.e. MultiNet).

But OSI killed Decnet

[shoppa]

The coming of OSI and it's asinine 7-layer model stiltified DECnet in the 90's. I'm sure that being OSI-compliant was a big deal at the time, but nobody cares anymore. And other than crossing the t's and dotting the i's to meet some government spec at the time, nobody really wanted it.

Before OSI, DECnet was sleek, widespread, easy, and portable across many platforms.

After OSI compliance, it was sluggish, cantankerous, difficult, and verbose.

Ahhh, VMS and DrECknet

[YankeeInExile]

I remember having a heterogynous network with VMS w/ the CMU-TEK TCP/IP package and Sun 4 with DECNET. You could telnet to the Vax, or at the vax say

SET HOST SPARKY

.

Those who wished to mock VMS would say "VMS Only has two commands, SET and LOGOUT"

Sadly, SET was terribly overloaded ... SET DEFAULT was how you changed (among other things) your current working directory; logging into another host across the network was SET HOST; disabling traps in a .com file was SET NOON;

I loved VMS, not because it was a speedy lightweight OS (it was absolutely the opposite in every way) ; but it was the friendliest OS out there for the hard-core assembly language programmer, and the VAX has an architecture that makes programming in assembly a joy.

Linux Decnet

[OlRickDawson]

As a user of the linux decnet stack, I would say the Linux decnet stack works pretty well for talking to old VAXen. There are still places with old VAX computer embedded in equipment that would take millions to replace. The Navy is using Charon VAX http://www.softresint.com/charon-vax/ in some places to keep from having to replace the attached hardware. SIMH http://simh.trailing-edge.com/ works very well for emulating a vax, but is software only. A vax emulation running on SIMH on linux can talk decnet, and so can the linux machine it runs on. However, because DECNET sets the mac address as the decnet address, the Linux's decnet can't talk to the SIMH running on it. So, I had to put tcp/ip on the simulator to get them to talk. It would be nice if Linux's emulator could set it's mac address at runtime, and have several, so it could to the routing, and talk to the SIMH emulator, but it isn't possible now.

Re:Summary of tech advantages?

[whit3]

Excellent question! Piddling little things like performance
and does-my-router-know-it aside, the DECNet wasn't
just a protocol, it was an enhanced user experience.

Instead of just transferring files, you could refer to a
file on a foreign computer by name (a facility similar
to our DNS (domain name system)). The network access
was transparent.

So, every file open of "file" opened the file in your
current default directory.
Open "directory/file" and you can get the file in a subdirectory
Open "disk:directory/file" and you get the file on a specific
rooted filesystem (other disk drive, usually)
And, open "outofstate::disk:directory/file" and you have
access to any known node (other computer) whose disk
and directory are readable (permitted) through the network.

The beauty of it is, there's no need to recompile the program,
just to feed it the string (filename and other info all go into
the same OPEN command).

Everyone using the internet with named URLs (universal
resource locators) and DNS (domain name service) has
similar capabilities nowadays, but DECNet users had it
two decades ago. And they had it in ALL cases of file
access. You could tell the help utility to read
helpfiles from Stanford's SSRL physics lab, or tell the
print output to go to a teletype in Maine.

And DECNet used (originally) mainly LAT networking protocols,
not TCP/IP, because it predates the internet; I have a short
stack of LAT network boxes that don't know TCP/IP, but
they'd be hard to replace this week (and they're all 10base2 or
somesuch, which is another issue...). There's nothing
intrinsically LAT-based about the DECNET, it's just the
historically original pairing; I presume DECNet and TCP/IP
are mainly cooperative these days.