[ih] NCP and TCP implementations

Noel Chiappa jnc at mercury.lcs.mit.edu
Wed Jul 22 08:35:07 PDT 2020

    > From: Jack Haverty 

    > I used a PDP-10 (Tenex) to cross-compile for the 11/40 where Unix ran.
    > I don't think I had to do much if anything to make the Macro-11 code
    > able to assemble using the PDP-10 tools.

I think that may have been how the code was originally done, at SRI.

When we first got it at MIT, Dave assigned some Sikh guy whose name escapes
me to work with it, and he was working on it on LCS's Twenex, MIT-XX. I
assume he was using whatever SRI had been using to assemble it. (According to
sources I was just looking at, he seems to have added support for the
LCS Version I ring.)

When I startedworking with it, the DSSR (ex-Delphi) guys on the 4th floor at
Tech Sq had brought up a DEC Macro-11 (in Macro-11) under Unix V6; I
converted Jim's stuff (mostly MOS; more below) to assemble under that, and
that too was pretty much 'assemble and go'.

I never worked with the TCP - I did try and get the Port Expander working,
but because someone who shall remain nameless, but I'm sure knows who he is,
had done an analog hack on DM's ARPANet interface [something to do with
grounding on the DH differential interface, IIRC], our LSI-11 ARPANET
interfaces (the SRI design, that used a DRV11), which didn't include the
opto-isolators of the IMP DH interface, wouldn't talk to the DM one, so that
was the end of that!
    > It might be interesting to compare Jim's TCP with my Unix version to
    > see how much "common DNA" remained. My code is an old paper listing
    > though, so it won't be as simple as just running 'diff' on the two.

I'll grub around in the dusty catacombs of that file system, and find
the earliest version of the TCP, and put it up and send you the

    > From: Michael Greenwald

    > I think it may have been Charlie Hornig who you are thinking of? (he
    > did early work on the Multics TCP implementation for Dave.)

No, Charlie worked on it after Dave first got it running (e.g. for the
bakeoff as ISI, a vivid memory, with the lights in the hallways out); it was
Drew Mason who worked on it to begin with; more here:


It's _possible_ that Bob Mabee did some design work on it before he left LCS,
but Dave or Drew would be the only ones who'd know about that.


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