A RAID system having a plurality of {HEAD ~ disk devices} and a RAID control device for controlling the plurality of disk devices, and storing same data in {TAIL ~ the plurality} of disk devices, the system comprising: 
A RAID system having a plurality of { HEAD ~ disk devices } and a RAID control device for controlling the plurality of disk devices , and storing same data in { TAIL ~ the plurality } of disk devices , the system comprising :
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH