[Simh] VMS/VDE: Almost there

[Rich Alderson]

> From: Zachary Kline <zkline at speedpost.net>
> Date: Tue, 6 Oct 2015 09:42:36 -0700

> as far as DecNet goes, am I correct in assuming that it's mostly useful for
> connecting clusters? I'm learning VMS almost entirely on my own, never having
> been exposed to it during its heyday.

DECNET predates VMS.

Prior to the triumph of TCP+UDP/IP as the primary networking protocol suite
in the world, there were a number of alternatives for local and wide-area
networks, generally manufacturer-specific.  DECNET was just one such; others
included IBM's SNA, ARCNET, Banyan VINES, PARC Universal Packets (PUP), and
Chaosnet from the MIT AI Lab.  Then there were private protocols on private
networks, such as that created by CompuServe which used DEC-20s as routers
(later replaced with clone systems from System Concepts).

DECNET is available under RSX-11M and RSTS/E on PDP-11s, Tops-10 and TOPS-20
on PDP-10s, and under VMS (and possibly Ultrix, I don't remember for certain)
on VAXen, and on VMS follow-on systems.  It is as far as possible agnostic
about what kind of system it was running on or connecting to.

DECNET provides host connectivity (like telnet), file transfer (like ftp),
electronic mail (like smtp+{pop,imap}), data sharing (like nfs), and loosely
coupled clustering.  Digital actually believed that it should replace all of
the IP-based protocols, since it was actively engineered instead of being a
series of experiments (in Digital's view) that grew like Topsy; Digital tried
very hard to make it a real implementation of the ISO X.400 pipe dream^W^Wstandards.

And I'm speaking as someone who worked on the TCP/IP side of things when that
was still the wild and woolly frontier.

                                                                Rich