[TUHS] PCS Munix kernel source

Paul Ruizendaal via TUHS tuhs at tuhs.org
Thu Aug 11 16:04:30 AEST 2022

> Message: 4
> Date: Wed, 10 Aug 2022 12:29:24 +0200
> From: Holger Veit <hveit01 at web.de>
> Subject: [TUHS] PCS Munix kernel source
> Hi all,
> I have uploaded the kernel source of 32 bit PCS MUNIX 1.2 to
> https://github.com/hveit01/pcs-munix.

Thank you for sharing this work, most impressive!

> MUNIX was an AT&T SVR3.x implementation ...

Are you sure? Could it perhaps be SVR2? (I don’t see any STREAMS stuff that one would expect for R3).

> The interesting feature of this kernel is the integration of the
> Newcastle Connection network

One of my interests is Unix (packet) networking 1975-1985 and that includes Newcastle Connection. I’ve so far not dived deep into this, but your work may be the trigger for some further investigation.

My understanding so far (from reading the paper a few years ago) is that Newcastle Connection works at the level of libc, substituting  system calls like open() and exec() with library routines that scan the path, and if it is a network path invokes user mode routines that use remote procedure calls to give the illusion of a networked kernel. I’ve briefly looked at the Git repo, but I do not see that structure in the code. Could you elaborate a bit more on how Newcastle Connection operates in this kernel? Happy to communicate off-list if it goes in too much detail.

I note that the repo Readme says that the kernel only does some basic IP networking as a carrier, but I also see some files in the tree that seem to implement a form of tcp (and that seem unrelated to the early Unix tcp/ip’s that I have seen so far). Or am I reading too much into these files?


Re-reading the Newcastle Connection paper also brought up some citations from Bell Labs work that seems to have been lost. There is a reference to “RIDE” which appears to be a system similar to Newcastle Connection. The RIDE paper is from 1979 and it mentions that RIDE is a Datakit re-implementation of earlier an earlier system that ran on Spider. Any recollections about these things among the TUHS readership?

The other citation is for J. C. Kaufeld and D. L. Russell, "Distributed UNIX System", in Workshop on Fundamental Issues in Distributed Computing, ACM SIGOPS and SIGPLAN (15-17 Dec. 1980). It seems contemporaneous with the Luderer/Marshall/Chu work on S/F-Unix. I could not find this paper so far. Here, too, any recollections about this distributed Unix among the TUHS readership?

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