Reply to post: Newcastle Connection, or Unix United

After four years, Rust-based Redox OS is nearly self-hosting

Peter Gathercole Silver badge

Newcastle Connection, or Unix United

Well, strictly speaking /../ was a super root with the other systems on the network seen as directories, so you would access files on system-B as /../system-B/usr/something, with the full file tree being available. You did need a common user and group space, of course, so the permissions would work properly.

I only saw the Newcastle Connection running using a Cambridge Ring in Claremont Tower, so I do not know how well it coped with multiple network types, but I there was a serial network driver as well.

The interesting thing about the Newcastle Connection was that it was a library only implementation, meaning that you did not have to make kernel changes to implement it, as long as you had a suitable network device in the kernel. You just needed to re-define the file handling library calls like open, close et. al., and ensure that you linked against the modified libraries in order to use it. If you had access to the source code of the libraries and commands linked against it (or even the pre-linked .o files and suitable libraries) you could add the facility to pretty much any implementation. I saw it on Bell Labs. Edition 7, BSD, Xenix/11 (Microsoft's port of Edition 7 for the PDP11), UniPlus, and I think Durham had it running against Ultrix/11.

I was needing some software for my PDP11, and I was helped by Dr. Lindsey Marshall who copied it from one system on the Cambridge Ring to a tape drive on another, by using a command like:

tar -cvf /../system-B/dev/rmt0 *

Because it honoured all device semantics, you could access devices on another system as devices, something that NFS took years to manage. Of course, AT&T's RFS available in R&D Unix could also do the same, something that I had fun playing around with it later when I was working at AT&T.

The Newcastle Connection was a very elegant system, but when I saw it, it was pretty much restricted to UNIX, although there as a project to write some client support for CP/M using a serial device as the network at Newcastle Polytechnic, but I don't think that the project was ever completed, although I was asked to add a serial driver to the PDP11 I looked after.

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