Does USB external drive need Master/Slave/CS?

I have read a couple of reviews that say that a USB external drive should have the disk set as Master.
Why is this?
What difference does it make if it is set to Cable Select?
Will TrueImage have a problem if it's not set to Master?

 

I would follow the review's suggestion. The USB external drive is the only drive on the USB "cable", so it is the 'master'. When using cable select, the 80 connector cable in a IDE configuration determines by position on the IDE cable which connection is master (if it's connected at the end of the cable farther away from the MB connection) or slave (if it's connected to the middle connector out of the two connectors possible). The USB 'cable' has no such 'signal' capabilities to the Motherboard, and only has one signal path, so use the master jumper setting on the drive.

Allen

 

The enclosures that I've bought usually specify how to jumper the hard drive. As far as I can recall, all specified Master. As long as the manufacturer had a preferred setting, that's what I've used. Otherwise, I used Master.