Hard drive cable question -

[bobgoodwin]

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.
>
> Mike

Ok, I jumpered the drives c/s and the computer can deal with that.  As 
long as the one set up for FC4 is on the master connector it boots and I 
can see the second drive.

The problem arose from the fact that I suspected an intermittent drive 
problem.  Apparently the failure was on the Windows drive while I was 
only using FC4 and MySql!  I ran smartctl and it indicated that both 
drives had a lot of use on them. One looked like more than four years 
power on time!  I assumed it was the bad drive and rep[laced it with 
another low time drive I had and then I began to have trouble.  The 
computer would not boot no matter what I tried.

Now I pulled the one I thought to be usable [but is bad, I just tried it 
again] and replaced it with the "bad" drive I had set aside and the 
computer will boot FC4 with that drive plugged into the c/s master 
connector.  Hwbrowser and fdisk show both drives.  So next to start over 
and install W2k on the other drive, I guess Windows will want to be the 
master and I will most likely wind up reinstalling FC4 with grub in the 
MBR on the Windows drive.

If nothing else I have learned something about configuring hd and their 
jumpers ...

The information has been helpful and appreciated.

BobG