Patent ID: 8402210

Claim:
A storage system comprising: a plurality of disk drives configured to store data sent from a computer; and a controller configured to control input/output of the data, wherein the controller appends data identification information to each of a plurality of logical data blocks corresponding to each of a plurality of a sectors that are physical storage regions in the plurality of the disk drives, wherein the data identification information indicates whether the data sent from the computer is stored in each of the plurality of blocks, and wherein the controller creates a parity logical data block P 0 , based on the plurality of logical data blocks, and creates parity part data identification information which indicates whether the data is stored in at least one sector in the plurality of sectors and appends the parity part data identification information to the parity logical data block, wherein, if the controller receives a format request, the controller stores unique data in at least one block of the plurality of logical data blocks, appends a guarantee code including a logical address and a longitudinal redundancy check to the at least one block, and configures the data identification information and the parity part data identification information to indicate that stored data is not sent from the computer, wherein the controller checks the parity part identification information, and wherein the controller determines whether to perform a storage function to the plurality of the logical data blocks by referring to a result of a check of the parity part data identification information.