I have no evidence why it should technically be that way either, but I can tell you it's not just a "second or third hand cable select misconception". It is specifically stated that way in all the drive literature that I've read about those 80 pin connectors.

Almost all cables are color-coded to help you remember the difference: the black connector for master, the grey one for slave, and the blue one for the motherboard. Some cables actually have the words "master" printed by the end connector, and "slave" by the middle one.

So there must be some reason why they go to this effort, and given that doesn't take very much effort to arrange your drives such that they can be plugged in this way, I've never really thought to question it. As to whether you don't lose performance the other way, I have no idea, but that would be interesting to know.

John

Further research led me to the same document that Mark quoted earlier. This is the ATA6 specification used by hard drive manufactures.

From my reading, the documents explicitly forbids single drive, Ultra DMA configurations with the master on the middle connector. See section 4.1, Cable configuration for this evidence. (You are using UDMA, mode 3, or greater, or you wouldn't have the problem above.) You have another drive on the end, so this is irrelevant.

The spec also mandates (section A.1.2, Mark's image above) that the Device 0 (master) connector be colored black and at the end of the cable and the slave be colored grey and placed in the center of the cable. No technical reason is given as to why, or whether it would work in a swapped two drive configuration like you have, but it is The Spec (tm).

In response to your question above, in the ATA spec, the term Device 0 is used as a synonym for master. This is given as definition 3.1.31 in the ATA spec listed above.

So according to the ATA spec, your current setup is incorrect and not guaranteed to work. However, I would guess that the standard of putting the master on the end arose from the problem people putting the master in the middle in single drive configurations, and labeling them this way just makes it easier. For me though, I'd rather just plug them in according to the standard and not worry about it.

John

Almost all cables are color-coded to help you remember the difference: the black connector for master, the grey one for slave, and the blue one for the motherboard. Some cables actually have the words "master" printed by the end connector, and "slave" by the middle one.

According to one of the articles I linked earlier, the reason for this marking scheme is to prevent someone from dangling that end connector "loose" in a single-drive configuration (which I *do* acknowledge and understand). Not because the device order is critical in a two-drive configuration.