RAID can work with IDE, SATA, or SCSI drives. It stands for Redundant Array of Inexpensive Disks. To use RAID, you have to have a controller, some types of which are now included on motherboards. It can be used for either performance or backup reasons. There are many different "levels" of RAID--the most common types are RAID 0, 1, 5, 10, and 0+1.