A backup utility allows users to copy, or back up, selected files or an entire hard disk to another storage medium such as CD, DVD, external hard disk, tape, or USB flash drive. During the backup process, the backup utility monitors progress and alerts you if it needs additional discs or tapes. Many backup programs compress, or shrink the size of, files during the backup process. By compressing the files, the backup program requires less storage space for the backup files than for the original files. Because they are compressed, you usually cannot use backup files in their backed up form. In the event you need to use a backup file, a restore program reverses the process and returns backed up files to their original form. Backup utilities include restore programs. You should back up files and disks regularly in the event your originals are lost, damaged, or destroyed. Instead of backing up to a local disk storage device, some users opt to use online storage to back up their files. Online storage is a service on the Web that provides hard disk storage to computer users, usually for free or for a minimal monthly fee