Recording medium, the data processing apparatus and data processing method

A recording medium, in addition to the recording area of ​​the nonvolatile, host interface unit, a control unit, providing the update notification unit. Control unit with read and write data in the recording area, via the host interface unit provides data and update information recording area in the data processing device. In particular, the present invention is characterized in that for updating the update information of the update notification unit immediately before the data recording area is updated. And the value of the update notification unit to referable and updatable from a data processing device. Data processing device that holds the update information update notification unit, stored in the recording area data can be determined not to have been updated by the other data processing apparatus. By doing this, the effectiveness of the cache information it becomes possible to confirm, it becomes possible to confirm the validity of the index file.