摘要 |
A controller determines whether data stored in a first storing area should be flushed to a second storing area or a third storing area. When flushing of data in a track unit from at least one of the first storing area and the second storing area unit to the third storing area unit is determined, the controller collects data included in the flushed data in the track unit from at least one of the first storing area and the second storing area including the storing area from which the flushing of the data is determined, merges the flushed data and the collected data, and writes the merged data in the third storing area. |