Anonymous Reader writes "Ubuntu Linux (other Linux distro also able to save data on external USB hard disk or USB pen drive) has this nifty feature that allows saving both data and desktop settings on USB pen or USB hard disk.
'casper-cow' is a special label on an ext2/ext3 filesystem or partition. You need to use e2label command to assign the label on USB pen or hard disk drive. If this label found Ubuntu Linux will use the USB device to store desktop information as well as your data/applications. The idea is very simply, "you are able to carry your desktop anywhere, anytime"."