[Coco] SCSISYS question
t.fadden at cox.net
Sat Sep 20 13:43:06 EDT 2008
Gene Heskett wrote:
>> As to your thread, I have everything in a pc case, so the cable is less
>> than 2 ft. It was split all the way. I had no terminators installed.
>> Having trouble with /h1 after reviving the coco, I ended up making a
>> cable as you describe with all 50 wires except at the controller. Wasn't
>> the problem, but I ended up with a better cable! ha ha ha the
>> connectors from the drive assy to the disk circuit board were corroded,
>> and after cleaning up all the drive cables I got it working again.
>> Term power should only supplied by one device on the chain. with 18in
>> cables no term power probably works.
> If you sacrifice enough virgins. True scsi is an open collector bus, and must
> have pullups in the form of terminations on each physical end of the cable.
> They try to match the cable impedance, absorbing the echos. The echo is an
> interchangeable term with vswr in the radio/tv business, and the less vswr
> the better.
Ha Ha Ha, I am not real up on the technical specifications only
speaking from 20 years of working with
scsi systems as a support engineer for Sun Microsystems. What is
correct/spec, and what you can get by
with are not always the same. :-)
>> Any hoo, any info you could provide as to getting scsisys2.2 would be
> I think the scsi driver now in Nitros9-3.2.8 is probably its equal if not
> better than 2.2. The advantage of 2.2 was supposedly enhanced speed, but
> even the original 1.1 could do a megaread in 13 seconds, where theoretical is
> 11 at the coco's clock speed. scsisys-2.2 to a Maxtor 7120s and myram to a 2
> meg disto kit can both do it in 11 seconds so there wasn't a huge difference.
I will look into this, up to now, I have not seen much for Disto 4in1
controllers with no multipak. And not
being intimate with the code, I wouldn't know just what to tweek to
make them work!
Thanks for the reply.
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