hello

> I know I would need a star coupler to do anything useful with 
> this, right?

im not sure if you can hook two points up directly or if you really need 
the coupler. all a star coupler is is a few very fancy transformers in a 
shielded box. (it's really elegant how dec did that) 

> However, I'm not eager to run an HCS as I don't really want to 
> build a cluster around common storage. Instead, I was wondering 
> about other uses of the CI bus. I heard it is pretty impressive in
> terms of throughput, so would be a waste if it ended up unused. 
> 
> And since a 100-TP Ethernet card does not exit for VAXen, I wonder 
> whether one could use a CI bus as a data link layer for IP? Not 
> having any documentation about it I can't really say how, and not 
> even having a working machine (yet) it certainly is all theoretical. 
> But I wonder that this super CI link technology is not put to more 
> interesting use than just sharing mass storage (and if built with 
> RA80's one can hardly even speak of "mass" anymore :-).
> 
> So, I could imagine using CI as a link layer for IP just like 
> Ethernet. Anyone ever tried that or knows otherwise that it 
> cannot work? 

i dontknow that anyone did it, but i dont see why not. 

> 
> My CI interface has 4 connectors "A" and "B" for each 
> input "->0" and output "0->". Will one connection to a star
> coupler use all four of those or only two? How absolutely
> certain is it that one cannot make a direct link between two
> machines without a star coupler? Like you can make a direct
> link between two 10/100-TP ethernet ports with a crossover
> cable? One would simply cross the input connector of one machine 
> over to the output connector of another machine and vice versa.
> 
> Does one have access to the physical layer with the CI
> adapter cards or is one confined to the MSCP? I could imagine
> that the MSCP implementation of the CI controller has all kinds 
> of built-in autodetection features that would refuse a direct 
> link between computers, or even any communication between 
> computers on the data link and network layers. If so, it will 
> not work. If, however, there is a way to bypass the MSCP or 
> circumvent any auto-sanity-enforements, one could either implement 
> IP over raw CI data link or IP over MSCP.


its the other way around with MSCP: CI is a protocol, MSCP is run over CI 
much the way NFS is run over IP. my hat is off to whoever hacks in CI 
support, that will mean clean DSSI support, the use of DSSI for 
networking, etc (i am already imagining my VAXen doing ip over DSSI! 8-)
but it wont be a very easy job. I can xerox the appropriate parts of a 
couple manuals i have which tell about DSSI, and i have some 
documentation for unibus CI adapters, though not programming information,
which i'd gladly send you a copy of. Look in ultrix though, there is CI 
support there. 

> 
> insane thoughts?
> -Gunther

no, its a very real idea, just one that nobody has attempted yet. 
isildur