"Arno Wagner" wrote in message
In comp.sys.ibm.pc.hardware.storage Timothy Daniels wrote:
"Arno Wagner" wrote:
glee wrote:
It is my understanding however (and the recommendation of the
manufacturers), that 40-pin, 80-wire IDE cables *do* require particular
devices to be attached to particular connectors on those cables, and that
the end connector *not* be left vacant. This is especially true in the
example given in the original post: using Cable Select.

In fact cable select is the only reason for this. There is no other
one. If you jumper the devices to slave/master you can have them in
arbitrary order, number and position on these cables.


You are correct that *on a single IDE channel*, the device arrangement
can be Master/Slave or Slave/Master or single Master or single Slave.
What is not allowed by the IDE controller, though, is Master/Master and
Slave/Slave on the same channel. But on different channels, you could
have ch.0 Master/ ch. 1 Master and ch. 0 Slave/ ch. 1 Slave and
ch. 0 Slave/Master/ch. 1 Master/Slave. The arrangement prohibited is
having the same jumpering for both devices on the same IDE channel,
i.e. on the same cable. That is imposed by the controller's need to be
able to tell the two devices apart which are on the same cable. I think
that's what you intended to express, but it wasn't clear.

Sorry.

Yes, that was what I wanted to say.

And that's what you said. Too stupid even to understand it's own ramblings.

Of course there is not physical interaction between multiple IDE busses /
channels (of which you incidentially can have more than two or only one).

Babble, babble, rant.


And the implications go farther: A Slave HD can be the "boot drive"
just as well as well as a Master HD. All that is required is that the HD
be at the head of the HD boot order. The default settings (or settings in
BIOSes which don't enable adjustment of the HD boot order) put the
Master on ch. 0 at the head of the HD boot order. But this can be
changed by readjustment of the HD boot order. Indeed, it's quite
legitimate to have the Slave on ch. 1 (the secondary IDE channel) be
the "boot drive".

Again true.

It is a start-up issue for the device detection only.

Nope. Device initialization at power-up or reset only.

Not for booting.

The Master is supposed to be detected first. Then the slave.

Completely irrelevant.

After that both are identical, except that they have different
select signals.

No they don't.

And yes, the BIOS is free to assign them any order wanted.

Arno