Patent ID: 7818495

Claim:
A storage device equipped with one or more flash memory modules, wherein one or more said flash memory modules comprises: at least one flash memory chip for providing a storage area; and a controller for controlling the reading and writing of data from and into said at least one flash memory chip; and wherein said controller performs deduplication of eliminating duplicated data by storing a logical address of one or more corresponding logical unit memory areas in a prescribed management information storage area of a physical unit memory area defined in said storage area provided by said at least one flash memory chip, and executes a reclamation process of managing a use degree as the total number of said logical addresses stored in said prescribed management information storage area and a duplication degree as the number of valid logical addresses corresponding to said physical unit memory area for said physical unit memory area, and returns said physical unit memory area to an unused status when a difference of said use degree and said duplication degree exceeds a default value in said physical unit memory area.