Symantec Backup Exec is an enterprise-level backup assistant application. It allows you to configure regular backups of data from single computers to entire server farms. Simply configure drives, media and data locations, and Backup Exec can run your jobs indefinitely, letting you know if any issues arise. Once your tape drive is set up in the application and you've created a job backing up your data, you must set up media, or tapes, in a media set. You direct your backup job to pull media from a certain set, so you have to make sure that a media set of that name exists.