Date : Wed, 23 Nov 2005 15:10:39 +0000
From : Jules Richardson <julesrichardsonuk@...>
Subject: Re: Cambridge ring interface
Eelco Huininga wrote:
>
> In the Electron, BBC and Master memory map the area between &FC30 and
> &FC3F is reserved for the Cambridge Ring Interface. What was this
> interface used for?
I saw recently that CR was an Acorn design - but this was only in a passing
reference in an article and didn't give any details. Google turns this up:
http://en.wikipedia.org/wiki/Cambridge_Ring
... following the links suggest that it was presumably a joint project between
Acorn and Cambridge uni (I've only skimmed the data so far).
> From the sound of it I'd guess it's some sort of LAN
> interface for a network used at Cambridge university.
It's a complete transmission protocol, and at least in the UK was quite
popular at one time, particularly in academic places. I seem to recall it
having some desirable properties over other technologies around at the time
(like Ethernet and IBM Token Ring). Presumably because it's a token ring
design it stands up much better under load than Ethernet networks did too...
> Has anyone ever seen one of these, and is there any documentation still
> available?
My University (UKC down in Kent, UK) threw all of their CR equipment out in
the early 1990's. I *used* to have some of it but sadly scrapped it all for
useful bits quite a few years ago - I wish I'd kept it now as I don't know of
an operational CR network anywhere.
My recollection at UKC is that it was used as a high speed transport for
character data between terminals and servers, with terminals connecting via
concentrator units rather than hooking up direct (so I've never seen nor heard
of a BBC with a direct CR interface, for example)
I'd be interested to hear any information that you find out! I'll give a
couple of my hardware contacts within Cambridge uni a prod and see if they
know of anyone who can provide more details. (The name David Greaves on that
website sounds very familiar for some reason!)
cheers
Jules