[TUHS] Unix NCP protocol stack for ARPANET

Lars Brinkhoff lars at nocrew.org
Mon Oct 25 19:26:05 AEST 2021

Clem Cole wrote:
> > Has any other NCP implementation for Unix survived?  From old host
> > tables I think there may have been some VAXen online before the
> > switch to TCP/IP.
> Hmmm... I find that interesting because Stan Smith and I wrote the
> original IP/TCP for the VAX in 1979/1980 when we were at Tektronix
> [...].  When Stan and I started that work, I had looked everywhere I
> could think to find an NCP implementation, and never found one.

That seems consistent with host tables I see.  According to those, there
were no VAXen on the ARPANET in 1980.  However, there were a a dozen or
so in mid 1981; mostly VMS.  (I'd also like to ask about NCP for VMS,
but this is TUHS.)

In early 1982 the number of VAXen has doubled, and out of those 10 are
running Unix including prominent sites like BBN, CCA, PURDUE, RAND, UCB.
Here's the rub.  Some hosts may have jumped the TCP/IP gun ahead of the
1/1 1983 flag day.  The host tables don't say.  Could it be that all
those VAXen were running experimental TCP/IP in January 1982?

> You tell me, but I was under the impression, that you folks at MIT did
> a ChaosNet interface, IIRC, so there may have been some sort of
> conversion on your LAN, but I really doubt there was a real NCP
> running.

The MIT host tables do show the Chaos networks, but I don't include
those in the count.

More information about the TUHS mailing list