>I can't find anything in there saying that the drives in a master/slave >configuration "must" be physically positioned a certain way.

Here: I'll attach two pages from the ATA6 standards.

For the now standard 80W cable:


But for the 40W cable, oddly enough they still suggest connecting drives the other way around, probably cuz the interface speed is slow enough to tolerate it and it is more convenient for in-case connection of a CD/DVD drive (slave) and an internal hard disk on one cable.



-ml