Replies inline

On Mon, Oct 10, 2022 at 3:48 PM Lars Brinkhoff <lars@nocrew.org> wrote:

> 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.
>
>
Well, there is an impio.c in the BBN TCP code which has #define NCPs, which
I used to rebuild the original impio.c; although this is very much a devil
in the
details situation.

I do need to do a readthrough for the VDH driver, which says its for "very
distant hosts".
I think that might be for the radio links to Hawaii and the UK? I vaguely
remember coming
across that term in my reading, but I'm drawing a blank ATM.

I did try to run the unix binaries in green and green47, but they seem to
be configured
for a RL0x drive of some sort; the driver is in the NOSC source, so it
might be possible
to get running, but without the host binaries, you'r enot going to get far.

> 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.
>
>
Well, I'm not sure if its trying to initialize the IMP on startup; there's
a userspace daemon,
ncpd which talks to the /dev nodes to do stuff; with network nodes showing
up as /dev/net/*host.

I did determine I at least seem to make it to sched() with my home cooked
kernel, but I can't even
start in single user mode.

Honestly, it reminds me of Plan 9 more than anything.


> > 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.
>
>
Will do. ITS feels like an extremely deep (if interesting) rabbithole :)


> > 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.
>
>
Yup, that's what I figured. I've been trying to evaluate how much survives
here, but
my general feeling is one of the UNIX stacks might be recoverable, plus the
ARPA
stuff in ITS. I don't know if a runnable build of TENEX has been archived,
or if ARPA
stuff for TOPS-10/20 survived.

I also want to look into System/360 and 370, but I get the sense none of
the mainframe stuff survived.

The other problem is of the surviving stacks, they all seem to be for the
later 96-bit leader,
I'm not certain if any of the IMP software that has been archived is new
enough to work with that.

That said, that isn't an insurmountable problem.
~ NCommander