The invention further includes a control unit, when there is no access from the host unit to the logical unit for a predetermined time, for determining the disk units corresponding to the logical unit based on information recorded in the management information recording device and performing power saving of {HEAD ~ power supply} for {TAIL ~ the disk units} 
for
The invention further includes a control unit , when there is no access from the host unit to the logical unit for a predetermined time , for determining the disk units corresponding to the logical unit based on information recorded in the management information recording device and performing power saving of { HEAD ~ power supply } for { TAIL ~ the disk units }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL