Patent ID: 7444460

Claim:
A data storage device including a data storage unit and a control unit for controlling inputting and outputting of data to or from the data storage unit, wherein: the data storage unit is divided into blocks each including a plurality of pages each having a predetermined storage capacity, and the data storage unit includes a data area for storing user data and a management information area for storing management information including address information used to access the data area; in the management information area, file management information including address concatenation information associated with a data file stored in the data area is stored; and the control unit executes a process of writing updated file management information such that: previous file management information is retained in a page in one of two different blocks forming a block pair, and the updated file management information is written in a page in the other one of the two blocks of the block pair, wherein the block pair is assigned in advance at the same time interval and comprises an even block and an odd block, and wherein when previous file management information is written to the even block, updated file management information is written to the odd block, and wherein the even block and the odd block are then used alternately for storing updated file management information and previous file management information.