Patent ID: 7716412

Claim:
A data storage apparatus connected to a host apparatus, data stored in the data storage apparatus being accessed under the control of the host apparatus, the data storage apparatus comprising: a storage unit managed using a logical block address; a memory; a storage control unit configured to store a free area control table transmitted from the host apparatus in the storage unit, the free area control table storing information on a free area in the storage unit; an expanding unit configured to: (a) read out the free area control table stored in the storage unit; and (b) expand the free area control table in the memory; a data recording unit configured to record data transmitted from the host apparatus into a free area in the storage unit based on the free area control table expanded in the memory in response to a predetermined command transmitted from the host apparatus; a table updating unit configured to update the free area control table expanded in the memory after the data recording unit has completed a recording operation; a transmission unit configured to transmit to the host apparatus updated information included in the free area control table which has been updated by the updating unit; and a determination unit configured to determine whether a free area control table stored by the host apparatus is the same as said free area control table expanded in the memory, wherein when the determination unit determines that the free area control table stored by the host apparatus is not the same as the free area control table expanded in the memory, the transmission unit transmits to the host apparatus information included in the free area control table expanded in the memory.