The RocketRAID 3522 is a Serial ATA (SATA) hardware RAID controller card that enables the Mac to drive a SATA-based RAID system. It features two mini Serial Attached SCSI (SAS) interfaces and supports connections for up to eight SATA II-equipped hard disk drives. RAID levels supported include 0, 1, 3, 5, 6, 10 and 50; you can also use the controller card to access a JBOD (Just a Bunch of Disks). The card also interfaces with eSATA and multilane interfaces.
The firmware update lets a 2006-era or newer Mac Pro or Xserve equipped with the card to boot from it. The card can boot to Mac OS X from a single drive or to a RAID 1 drive. It works in both Mac OS X v10.4 and 10.5.