Each file created on the computer is basically saved to the hard disk first. Now the file has been saved, but it is not safe. If a virus, a disk crash, a program error, or user error damages the file, it is gone. For scanned data, this may not be fatal, since the analog source is usually still available; but the time needed for rescanning can be considerable. In this case as well, backup is mandatory. Backup and management must be economical, simple, and effective. The more complicated the backup, the more likely it is to be neglected. Problems with backup can usually be traced to user error or infrequent use due to awkwardness.