backup types - technical definition

The selection of files for backup purposes. See LAN free backup.

Full Backup
Backs up all selected files.

Differential Backup
Backs up selected files that have been changed. This is used when only the latest version of a file is required.

Incremental Backup
Backs up selected files that have been changed; but if a file has been changed for the second or subsequent time since the last full backup, the file does not replace the already-backed-up file, rather it is appended to the backup medium. This is used when each revision of a file must be maintained.

Delta Backup
Similar to an incremental backup, but backs up only the actual data in the selected files that has changed, not the files themselves.