Gene Heskett wrote:
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
Ok, I'm glad I asked that question. It clears up some gaps in my
knowledge, I hadn't considered the effect of unterminated lines on fast
pulses but that would be a reason for always connecting both ends of the
cable, leaving one end free, using the center connection only would
leave a bunch of unterminated stubs which might cause some ringing.
I did not realize that alternate wires were grounded either ...
Anyway thanks to all.
Bob Goodwin
