Patent ID: 7558937

Claim:
A disk array device comprising: a control part having a processor and a memory and controlling the disk array device; a plurality of disk devices storing data, the data being read/written by said control part, wherein the memory comprises: a system area managed by an operating system; a cache area serving as a cache memory to temporarily store input/output data; and a table area storing management/control information relating to the disk array device; wherein the memory is capable of setting a first area which is not in use in the cache area as the table area, using the first area, and resetting the first area as the cache area after use; and the memory is capable of setting a second area which is not in use in the table area as the cache area, using the second area, and resetting the second area as the table area after use, while the disk array device is in use; and wherein, when data unwritten to said disk device exists in part of the cache area to be allotted as the table area in response to an expansion request of the table area, priority write control of the data unwritten to said disk device is executed.