Hard drive cable question -

Gene Heskett gene.heskett at verizon.net
Thu Feb 23 01:03:51 UTC 2006


On Wednesday 22 February 2006 18:48, 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.
>
Then you have an ata100 or faster cable.  And yes, in many cases, the 
drives position on the cable is important.  As in scsi systems, the 
last drive on the cable must assume that its job is to terminate the 
cable and try, by the termination enabled when is either jumpered as 
Master, or is in CS mode and the last drive, to absorb the echos from 
the signal transitions.  By playing mix and match, possibly with the 
drive thats functioning in master mode, on the middle connector, and a 
drive set as slave on the end connector, you are just asking for data 
integrity problems.  The signal edges under those conditions will ring 
like a bell causeing data errors galore.

Also, if the cable is a cable select cable, as evidenced by having a 
black connector on what should be the motherboard and, and 2 other 
colors are used for the other two connectors, then the drives should be 
jumpered for CS, and the master drive must be on the far end of the 
cable.

Also as a reference, these 80 pin cables should NEVER be turned end for 
end, as its only the black connector that is suppposed to be plugged 
into the motherboard that has the proper grounding connected to the 
alternate wires in that 80 conductor cable, thereby serving as 
interconductor shielding by haveing a grounded wire between each active 
wire, thereby reducing crosstalk by a considerable amount.

>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?

Untrue, that is used only rarely even in the scsi world.

>Can someone clear this up for me.
>
>Thanks.
>
>Bob Goodwin   Zuni, Virginia

-- 
Cheers, Gene
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