[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]

Re: Hard drive cable question -



Mike McCarty wrote:

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.


If you have more wires than pins, you almost surely have a CABLE SELECT
cable. In fact, if your cable is less than five years old, you probably
have CS. Which end goes where depends on how you jumper your hard
drives.

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


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 ...


;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?


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 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?

Floppies have a "twist" in their cables, not hard drives.

Can someone clear this up for me.


HTH

Mike



[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]