FLASH memory is allocated to provide a data-storage device and management tables. The management tables may record logical-to-physical address mapping information in a hierarchical structure consisting of at least two levels. Further, in addition to the logical-to-physical address mapping information, the management tables may further provide a valid page count table and an invalid block record. The logical-to-physical address mapping information is updated after an update of the valid page count table is completed. The invalid block record is maintained based on the valid page count table.