Digidesign does not qualify any one style of file back up.* CD-R, DVD-RAM, and Tape Backup are just a few of the options.- CD-R's are probably the most common method, however will only store approximately 650-700mb. Some are re-recordable.- DVD-RAM's can hold up to 5.2 gigs and are re-recordable.- Tape Backup systems (such as Mezzo) are capable of storing 40+ gigs and are re-recordable.You should never back up your audio in "Compression" mode. Use a "Native" mode. Any system that can backup/restore SDII or other compatible files will work. Check with manufacturers regarding their systems for capacity and other specifications.*Back up & restoration software & hardware will vary in their features, specifications, and results depending upon their speed, capacity, and error checking/correction capabilities.