On Thursday 23 February 2006 21:35, Gene Heskett wrote:
>On Thursday 23 February 2006 16:18, Mike McCarty wrote:
>>bobgoodwin wrote:
>>> Mike McCarty wrote:
>>>> bobgoodwin wrote:
>>
>>[snip]
>>
>>>> If you use M/S jumpering on the drives, then in theory it doesn't
>>>> matter where you connect them.
>>>
>>> Except it appears to me that it matters as far as terminating the
>>> line properly is concerned. Ideally it would seem the termination
>>> should be at the far end where the master is connected to avoid the
>>> possibility of a mismatch at the end of the stub that would result
>>> if the slave is at the far end. How much ringing might occur and
>>> the severity of it's effect is an unknown? It would be interesting
>>> if I could get into the circuit and poke around with a scope probe
>>> ...
>>
>>Agreed.
>>
>>[snip]
>>
>>>>> I thought "cable select" cables had wires obviously crossed in
>>>>> the ribbon cable but that may not be true with this 80 wire
>>>>> ribbon?
>>>>
>>>> Not crossed. For CS, the drives have resistive pull-ups on them.
>>>> The MB pulls down one line. The wire to this line is *severed* as
>>>> the slave connector, so the "master" sees a high, while the
>>>> "slave" sees a low on this pin. (The MB may have a pull-up and the
>>>> drives a pull-down, I forget the polarity.)
>>>
>>> If the h/d manufacturer provided this explanation this thread would
>>> never have started. I would have never asked any questions. It
>>> appears
>>
>>Well, just how much of the interface should they document? Each pin?
>>Just the Cable Select pin?
>>
>>> that I probably have cable select which I will try here in a little
>>> while. The drives can be jumpered for CS and I have 80 wire ribbon
>>> cables so it appears that should work if I understand everything
>>> I've read here? It would be helpful if the user knew that he was
>>> dealing with a c/s cable, there is no mark apparently other than
>>> the fact that there are more wires than connector pins to tie them
>>> to?
>>
>>Color of the connectors. Usually non-CS cables use just one color
>>of connector, presumably because they can get better volume
>>prices that way. CS cables are supposed to use blue for the MB
>>connector, black for "master" and grey for "slave", IIRC.
>
>And someone else quoted the last two in reverse. Can someone PLEASE
> go get one of these friggin cables and settle the argument? Good
> color vision required of course :)
Ok I just took the place apart, and the only two cables I have that
MIGHT be CS cables came with an original promise 20267 raid card that I
was going to use at one time for a raid here. Those two cables are
blue for the card end and its keyed too, grey for the (s/b slave) next,
and black for the end (s/b master) one. But I gave that up when the
horror stories about the 20267 started surfaceing on lkml. I don't
know if all its bugs have been coded around now or not.
>>Mike
>>--
>>p="p=%c%s%c;main(){printf(p,34,p,34);}";main(){printf(p,34,p,34);}
>>This message made from 100% recycled bits.
>>You have found the bank of Larn.
>>I can explain it for you, but I can't understand it for you.
>>I speak only for myself, and I am unanimous in that!
>
>--
>Cheers, Gene
>People having trouble with vz bouncing email to me should add the word
>'online' between the 'verizon', and the dot which bypasses vz's
>stupid bounce rules. I do use spamassassin too. :-)
>Yahoo.com and AOL/TW attorneys please note, additions to the above
>message by Gene Heskett are:
>Copyright 2006 by Maurice Eugene Heskett, all rights reserved.
--
Cheers, Gene
People having trouble with vz bouncing email to me should add the word
'online' between the 'verizon', and the dot which bypasses vz's
stupid bounce rules. I do use spamassassin too. :-)
Yahoo.com and AOL/TW attorneys please note, additions to the above
message by Gene Heskett are:
Copyright 2006 by Maurice Eugene Heskett, all rights reserved.
