[Simh] CI750 tech docs and VAX firmware

[Johnny Billquist]

On 2017-03-09 19:00, Paul Koning wrote:
>
>> On Mar 9, 2017, at 12:27 PM, Timothe Litt <litt at ieee.org> wrote:
>>
>> ..
>> With respect to an earlier question about CI emulation:  The best approach may be to emulate it as multicast ethernet.  Setup a couple of groups for each star coupler.  Each coupler supports up to 32 nodes.  For VMS, half o them hosts, half storage.  CI is a 50Mb/s (might be 70, but I remember 50 from the initial doc) CSMA/CD bus.
>
> 70 Mb/s is the number I always saw.

Me too.

>>  The cabling is redundant (A & B cables), so assign one MC group to each per star.  (Yes, there are DECnet drivers for on multiple OSs.  I think it was considered a multipoint medium with addresses related to (CI) node numbers rather than an ethernet (broadcast) - but it's been a while.)
>
> I don't think DECnet ever supported CI.  It certainly doesn't show up in the DECnet architecture specs anywhere.

It did support it. But if I remember right, it was kindof not really 
supported. The drivers existed, and was provided to customers, but I 
think VMS manuals mentioned it as some unsupported lines. I remember 
having tested it a little, and did get it to work.

Under Ultrix I also managed to get TCP/IP running over CI.

	Johnny

-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
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