Abstract: It is provided a data storage device which reads data from and/or writes data to a memory medium, comprising: an acquisition unit for acquiring management information which is recorded by a predetermined form in said memory; and a controller for converting the management information into an another form. The controller rearranges the management information to convert the management information into another form, and also the controller restores the converted management information to the predetermined form according to a relationship between a first identifier recorded on the memory medium and a second identifier recorded in the data storage device. When, for example, the two identifiers match, the acquisition unit can acquire the management information, and the reading and writing of data is enabled.