[ih] Early Unix networking

[craig at tereschau.net (Craig Partridge)]

On Mon, Oct 10, 2016 at 4:22 PM, Paul Ruizendaal <pnr at planet.nl> wrote:

>
>
> According to BBN Quarterly #28, late in 1982 Gurwitz changed the design
> from being run on a second kernel thread to being driven by software
> interrupts. The code appears to have been further developed and maintained
> by Gurwitz and Partridge as late as 1984. It is this evolved version that
> appears in the "deprecated" subdirectory in October 1985. Unfortunately,
> all the development between March 1982 and October 1985 on the "bbnnet"
> code is not covered by SCCS and also not included on the 4.1c and 4.2 BSD
> distribution tapes.
>
>
As I recall, the BBN code history is more complex post 1982.  It went
through several hands.

Rob Gurwitz moved from being programmer to project manager to, I think,
group manager between something
like 1981 and 1985.

By sometime in late 1982, Rob was the manager of the TCP/IP effort at BBN
and Dennis Rockwell, who had previously been a lead programmer in a group
at Duke doing UUCP/Netnews (I think that's right), was the
TCP/IP programmer.

Bob Walsh took over the code, still reporting to Gurwitz, in summer 1983.
By fall 1983, BBN found it needed someone to work with the Joy code in 4.1c
and hired me and taught me TCP/IP programming with Joy's code (rather than
the BBN code).  Sometime in 1985, I ended up helping Bob Walsh a little bit
in the 4.2 BBN TCP/IP code release, which was the BBN code rewritten to use
the socket interface rather /dev/tcp.  Sometime soon after Bob moved on to
other projects and Karen Lam was hired to work on the BBN TCP/IP (which
DARPA still funded).  Then Rob Gurwitz moved on and I was handed the
project and Karen reported to me and had moved to adding some features to
the Joy BSD code (I don't recall what).  Then Karen left and David Waitzman
replaced her and David worked on putting multicast into the Joy BSD code
with Steve Deering of Stanford.  After that, c. 1991?, the DARPA funding
finally ended.

Many details are likely not quite right here -- doing this from memory.

Two side notes:

* sometime during this period I recall seeing an insightful note from
Gurwitz about limitations of both the Joy and BBN TCP implementations in
Unix.  I'm hoping it was sent to DARPA and survives in a file somewhere.
The paragraph I remember best is a comment on the limitations of mbufs
(which apparently Gurwitz devised), which seemed prophetic (which is why I
remember it), when people sought to reduce the memory overheads during the
1990s.

* the Joy TCP was apparently a rewrite of the BBN TCP (vs. a from scratch
implementation).  As late as 1989, Berkeley would sometimes defend bugs in
the Joy TCP by observing they'd originated in the BBN TCP.

Thanks!

Craig


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