[CentOS] Trying to understand USB HD configuration

I am trying to understand how my USB drive is setup in Centos 5.5 -- especially since I made a mistake of backing up to it when it was not turned on.

The USB drive is accessed as /media/disk. However, when I did a backup WITHOUT the drive turned on, the data was put into the directory, /media/disk.

Now, when I turn on the USB drive (it is self-mounted in 5.5), the USB drive has been assigned "disk-1" -- understood. What I am missing is the "table" that contains the information pointing to USB drive, disk-1. I would like to reset the table so that "disk" is the USB drive and delete the data that is now on my main drive.

Hopefully I have explained the situation properly.

Todd