I have actually noticed that it "walks" as you plug it in and remove it.
The first time you put it in FC2 will find it and mount it into /mnt/diskonkey and it will be on sda1. Then each time you remove it and add it it will move up one sda2 and so on. So after the first time you put it in and it mounts it you will have to reboot to get it to work again.
Rebooting isn't the best solution. It's easier to rmmod usb-storage.
It's better still to use updfstab and gnome disk mounter (or it's KDE equivalent). You can have a clean setup where users can mount and unmount from the desktop without fuss.
-Cam
-- camilo@xxxxxxxxxxxx <--
