Backups created in Microsoft® SQL Server™ 2000 and SQL Server version 7.0 are stored using the Microsoft Tape Format (MSTF). MSTF is not specific to tapes; it can also be used for backing up to either disks or named pipes. Each time a SQL Server backup is performed, it forms a backup set. This backup set is stored in an MSTF unit called a media. MSTF media can store backup sets from different software.
Using the MSTF format allows SQL Server to work with administrative utilities and products from other vendors that manage MSTF format backups. SQL Server backup sets can share media, such as MSTF tape drives, with backup sets from other server software. SQL Server does not compress its backup sets, but uses the compression provided on MSTF backup devices.