On Fri, 28 Oct 2005 19:55:35 +0100, patrickp wrote:

On Thu, 27 Oct 2005 18:19:36 -0400, MCheu wrote:

The original 40 conductor IDE cables had full connections going to
both drive connectors. Those won't work with cable select.

The old 40 wire CS cables had a gap in conductor 28, between the two
drive connectors. The middle drive thus sees a connection and
declares itself master, and the one past the gap sees what looks like
a ground, so declares itself slave. That's how cable select works.
Yeah, I know, that's backwards from the normal master/slave
configuration -- keep reading before you nitpick.

Some were wired in a "Y" configuration, with a complete set of
connections going to the end drive (thus making it master) and a
branch leading to the middle connector. This middle branch had
conductor 28 broken, making the middle connector CS slave. This was
more in keeping with the traditional drive orientation.

Later cables were wired in the "Y" configuration but put the break
into the middle connector itself, so there was no external indication
that there was any difference between it and a "regular" cable. Since
pin28 is dedicated to cable select chores, it doesn't affect manual
master/slave configurations.

The 80 conductor cables are all supposed to be CS cables wired up in Y
configuration as described in that previous paragraph, so the
conductor 28 stuff should be invisible. However, it's conceivable
that someone could have just given a full connection to both
connectors. It wouldn't be the first time that I've seen an IDE cable
on the shelf that wasn't 100% conformant in some way (usually it's
just something silly like the colour of the connector plastic).

Actually, some 80 wire cables are wired with the centre connector as
master. I have a couple somwhere.

I was always told it was "best" to have the master at the end. No idea why.

--
http://www.petersparrots.com http://www.insanevideoclips.com http://www.petersphotos.com

Then there was the Eskimo girl who spent the night with her
boyfriend and next morning found she was six months pregnant.