On Jul 15, 2016, at 10:08 AM, Mouse <mouse at
Rodents-Montreal.ORG> wrote:
DECnet might be totally integrated and awesome,
but it's also
proprietary, seldom used,
I think it is only semi-proprietary. I've seen open documentation that
at the time (I don't think I have it handy now) I thought was
sufficient to write an independent implementation, both for Ethernet
and for serial lines.
DECnet is open in the sense that anyone can see or reprint the specs, and implement the
protocols. Arguably it is pretty similar to the BSD license (the "with
attribution" variant). And the specs were written with sufficient care that
following them is, in general, sufficient to create an interoperable implementation. For
example, I implemented DDCMP for RSTS from the DDCMP spec, and "it just worked".
This, by the way, is quite rare in protocol specs; it certainly is not true for many
RFCs, and for one I know of it wasn't even considered a worthwhile goal by the
document editor!
The only ways in which DECnet is proprietary is that the development work was done by
Digital and not others. And the name (DECnet) was a trademark. (Then again, so is
"Linux".)
Actually, the "done by Digital" is true only through Phase III. In Phase IV,
you get Ethernet (developed by Digital, Intel, and Xerox), HDLC (developed by various
telcos based on earlier work by IBM), and perhaps other bits. And of course, in Phase V,
a whole lot of the machinery is from OSI, though that was very much a two-way street
(IS-IS came from Digital's work on Phase V routing, as did OSPF). Finally, even when
one organization did the detail work in a particular area, various algorithms and
inspiration came from other sources. Dijkstra's algorithm is a good example, of
course, but there are plenty of others. (The softlink loop detection algorithm in DECdns
is another example of a decades old algorithm put to good work in DECnet.)
paul