Patent ID: 7406619

Claim:
A RAID system comprising: a host input/output circuit; a plurality of hard disk drives; a first RAID controller and a second RAID controller, each of said RAID controllers including a cache memory, and each of said RAID controllers electrically connected to said plurality of hard disk drives; in each of said RAID controllers, a processor electrically connected to said host input/output circuit and said cache memory; and a first serial attached SCSI (SAS) or serial ATA (SATA) (SAS/SATA) input/output (I/O) circuit associated with said first RAID controller, and a second SAS/SATA I/O circuit associated with said second RAID controller; wherein said first SAS/SATA I/O circuit includes a first SAS/SATA I/O chip having a first SAS/SATA I/O port and a second SAS/SATA I/O chip having a second SAS/SATA I/O port, and said second SAS/SATA I/O circuit includes a third SAS/SATA I/O chip having a third SAS/SATA I/O port and a fourth SAS/SATA I/O chip having a fourth SAS/SATA I/O port, and wherein said first SAS/SATA I/O port is connected to said third SAS/SATA I/O port and said second SAS/SATA I/O port is connected to said fourth SAS/SATA I/O port; wherein said plurality of disk drives includes a first plurality of hard disk drives and a second plurality of disk drives, each of said first SAS/SATA I/O chip and said third SAS/SATA I/O chip is connected to said first plurality of disk drives, and each of said second I/O chip and said fourth I/O chip is connected to said second plurality of hard disk drives.