Hard drive cable question -

[Gene Heskett]

On Wednesday 22 February 2006 19:12, Wolfgang Gill wrote:
>On Wed, 22 Feb 2006 18:48:24 -0500, bobgoodwin wrote
>
>> Does it matter which forty pin connector plugs into the master and
>> slave drives?
>>
>> I have come to the realization after struggling with some problems
>> that there are a lot more wires in the ribbon cable than there are
>> connector pins.
>>
>> I now see that Maxtor designates the connector at the end of the
>> cable as the "master" and the one just below it as the "slave."  I
>> presently have only one drive jumpered as master with FC4 running on
>> it and it ;doesn't seem to care which data cable connector is
>> attached to it, but when I put in the second drive, jumpered as
>> "slave" the computer won't boot.  I decided the drive was bad but
>> now I'm wondering? It may be the wrong connectors plugged into the
>> drives.
>>
>> I thought "cable select" cables had wires obviously crossed in the
>> ribbon cable but that may not be true with this 80 wire ribbon?
>>
>> Can someone clear this up for me.
>>
>> Thanks.
>>
>> Bob Goodwin   Zuni, Virginia
>
>Nope it doesn't matter. Drive selects are done with jumpers on the
> drive. All IDE 40/80 pin cables are straight through, so the drive
> itself govens whether it's master or slave. When I only have one
> drive, I use the middle connector, and hide the other one out of the
> way, to give me better casing air flow.

To do so is asking for data errors.  In the IDE system, its assumed that 
the drive jumpered as master will do the termination of the cable also, 
and to do that properly requires that it be on the end of the cable.  
Any cable hanging out the far end of the signal path is an electrical 
mirror, which if not loaded with the cables characteristic impedance 
with an ohmic load, will make the edge of the data signals ring badly, 
possibly corrupting the data.

This is in fact almost as critical as a scsi cable setup, where the 
common practice is to do it right, then sacrifice something to the gods 
just for insurance.

>Usually (Depending on brand of drive), the master drive is jumpered,
> and the slave drive isn't.
>
>Wolf
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>Open WebMail Project (http://openwebmail.org)

-- 
Cheers, Gene
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