Media overwrite protection levels

Full - Overwrites scratch media, which are media that contain data you are willing to discard, and recyclable media, which are media that are associated with media sets and have expired overwrite protection periods.
Partial - Overwrites imported media, which are media that was created by another installation of Backup Exec or some other backup product, and overwrite scratch media.
None - Overwrites all media, including those that have current overwrite protection
periods (allocated media).