Hi,

while I'm waiting for material to get on with my VAX project I
have some time for musings. Don't want to keep anyone from doing
good work though :-)

I found a blue coax cable in the trash at work. Looked like new.
About 7 or 10 mm thick in a roll of 1 ft diameter. Probably about
5 ft long (all estimates.) It has an inward-threaded connector
at each end. I can actually screw those on my CI bus connectors. 
From what I heard, I imagined a CI cable being a big pipe of 
at least 1 inch diameter, was I wrong and I do have a CI cable?

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

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? 

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.

insane thoughts?
-Gunther


-- 
Gunther Schadow, M.D., Ph.D.                    gschadow@regenstrief.org
Medical Information Scientist      Regenstrief Institute for Health Care
Adjunct Assistant Professor        Indiana University School of Medicine
tel:1(317)630-7960                         http://aurora.regenstrief.org