[TUHS] Attempting To Build NOSC and BBN UNIXs + ARPANET code

Lars Brinkhoff lars at nocrew.org
Tue Oct 11 23:57:07 AEST 2022

Michael Casadevall wrote:
> From what I got the impression From the docs, very early ARPA, you had
> systems directly on the network, but most users had to dial into a
> specific terminal machine, which, based on the comments on the RFCs,
> was less than ideal

Sounds like a TIP, "Terminal IMP".  It was an IMP with double the amount
of memory.  In the upper half there was software to talk to a modem pool
for dial-in access to the network.  "Less than ideal", sure.  Modem
speeds were often 10-30 characters per second.  Much more fun to sit at
a video terminal next to the host.

> VHD I guess was more to get more hosts online?

In some cases there was an IMP which hooked up to some local hosts, but
they also wanted to connect a computer that not in the same building but
in the area.  That's when a VDH type interface was used.

> The BBN with TCP stack is a bit mislabeled: it still appears to
> support NCP, but none of the client apps are there, but its directly
> built off the NOSC stack.

That's very good.  I hope the NCP support there is in good shape.

> it's probably a fork from earlier in development. 79-80 timespawn
> would have been *very* early in TCP's life

TCP had been underway since 1973.  Experiments called "TCP bakeoffs"
started around 1979.

> > Pluribus IMP emulator,  anyone?
> I do actually wonder how hard that would be.

I'm not sure.  I have the impression the Pluribus computer isn't well

It might not be too hard to write an IMP replacement from scratch.

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