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

[Lars Brinkhoff <lars@nocrew.org>]

Michael Casadevall wrote:
> part of impio.c is cut off. However, this isn’t quite as bad as it
> sounds. For example, by kitbashing both the original v6 source code,
> and the later BBN TCP code, I was able to create a sys4.c that builds
> and links which should be close to the original. Furthermore, it is
> possible to use the “vdh” target instead of the imp target to at least
> try and get the code building.

Too bad about impio.c!  Maybe something can be extracted from the
unix.greg binary?  I see there's also the ACC interface, another
alternative to IMP11A.

> My guess is it's either deadlocked waiting for the IMP, or there’s
> something wrong with the build.

Since you don't have anything backing the hardware registers for the IMP
interface, it seems likely something will be upset.

> Furthermore, I do know that I can run some of the ARPA level utilities
> in MIT ITS on CHAOSNET, which will be an upcoming project, although
> that is going to be a dive in and of itself.

It's complicated.  Many of the utilities have parallels between the two,
and some work on both.  And there's a server to provide a gateway from
Chaosnet to Arpanet.  Give me a ping when you're looking into ITS.

> I know IMPs have been emulated, and even have successfully routed
> packets, so I’m also trying to figure out how much would still be
> necessary to actually recreate a minimal ARPA network?

Reviving the host software, like you are are doing, is one vital part of
it.  Another it adding emulators for various IMP interfaces.  I.e. you
will not get anywhere without adding one of IMP11A, ACC, or VDH to SIMH.

For adding other nodes to the network, PDP-10 hosts are your best bet.
There isn't much else left.