DISK STORAGE DEVICE

PROBLEM TO BE SOLVED: To improve the throughput and prolong the lifetime of a nonvolatile memory in a disk storage device which writes write data, in a disk storage medium with a head. SOLUTION: In writing processing in which a physical sector size of a disk medium (3) is the integral multiple of a size of a logical block, a control unit (14) detects that there is write data for which writing of partial logical block unit within the physical sector size is performed; stores the write data of partial logical block unit in the nonvolatile memory (12), and after storing the write data of a plurality of logical block units that match the physical sector size in the disk medium (3); reports a response to a host. Accordingly, the throughput and prolong the lifetime of the nonvolatile memory are prolonged. COPYRIGHT: (C)2010,JPO&INPIT