Data storage device, method of storing data, and on-vehicle control apparatus

A data storage device that performs data storage control, comprising:

• a memory having a plurality of storage blocks each provided with an actual data area storing therein actual data, the memory being not able to overwrite data, and the memory erasing data in units of the storage blocks when the data are erased therefrom;
• and
• a memory control unit that performs control of at least one of writing and reading with respect to the memory, wherein
• a management data area storing therein management data for management is provided in the memory,
• the management data area is configured to be able to store therein writing-in-progress management data indicating that writing of actual data has started, validity management data indicating that the writing of the actual data has been completed, and pre-erasure management data indicating that stored actual data have been brought into an erasable state, and
• the memory control unit:
• when storage of actual data into a new storage block that is a new one of the storage blocks is performed,
• performs writing of the actual data into the new storage block after storing writing-in-progress management data into the management data area for the new storage block;
• after the writing of the actual data is completed, stores pre-erasure management data in the management data area for an old storage block that is the storage block where storage of the actual data used to be performed;
• thereafter stores validity management data in the management data area for the new storage block;
• determines a valid block having validity management data stored and no pre-erasure management data stored in the management data area thereof to be the storage block storing therein latest data;
• and
• determines, when the valid block is determined to not exist, a pre-erasure block having validity management data and pre-erasure management data stored in the management data area thereof to be the storage block storing therein the latest data.