Announcing TCP/IP for RSX-11M-PLUS

Noel Chiappa jnc at
Wed Jan 14 13:02:55 CST 2015

    > From: Johnny Billquist

    > And tcp/ip already exists. At least on TOPS-20.

There are at least two TCP/IP's for PDP-10's - the other, written by Ken
Harrenstien, is the one for ITS. I'm not sure how closely related the TWENEX
one is the TENEX one done at BBN - I vaguely seem to recall that DEC re-wrote
it extensively, but I don't know much about that code.

    > From: Pontus Pihlgren

    > Do you mean to say that bytes are 8-bit wide on PDP-11? Why would
    > PDP-10 be so much harder?3

TCP/IP header fields are all multiples of 8 bits. So anytime you want to
read/write one on a PDP-10, you have to start LDB'ing and DPB'ing through
byte pointers/descriptors all over the place. Which I'm sure is no biggie for
most experienced PDP-10 coders, but it would drive me bonkers.


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