Backup and Media Fundamentals
Information about backup history, backup devices, and media sets are stored in the system msdb database. This information is extremely useful in helping to understand and manage backups, such as to determine what databases and files have been backed up, what type of backups have been performed, and which backup sets are available for restore. Basic backup set and media set terminology are unchanged since SQL Server 2000, and the information in the backup history tables of both is similar, but with SQL Server 2005 there are some additional columns in the tables and one completely new table, called backupfilegroup.
The following system tables within the msdb system database store history information about backups: