A term used for making a copy of a file incase the original becomes corrupt or deleted by mistake. Backup of important files is normally forgotten by Internet beginners who learn by experience of losing vital data. Backup of data can be done on any computer storage device such as floppy disks, hard drives, zip disks, rewritable cd's and more. It is a good idea to keep the backup data in a different location to the orignial data incase of theft ot fire.