Patent ID: 8819387

Claim:
A valid data identification method, adapted to a memory storage device having a rewritable non-volatile memory chip, wherein the rewritable non-volatile memory chip comprises a plurality of physical blocks, each of the physical blocks comprises a plurality of physical pages, each of the physical pages comprises a data bit area and a redundant bit area, and the physical blocks are grouped into at least a data area and a spare area, the valid data identification method comprising: configuring a plurality of logical blocks to be mapped to the physical blocks in the data area, wherein each of the logical blocks comprises a plurality of logical pages; receiving a data to be written by a host system into a specific logical page among the logical pages; selecting a substitute physical block and writing the data into a specific physical page in the substitute physical block, wherein the substitute physical block is selected from the spare area and mapped to the logical block corresponding to the specific logical page; recording an address of a physical page in which a previous data corresponding to the specific logical page is written into the specific physical page; identifying a first physical page among all the physical pages corresponding to the specific logical page, wherein an address of the first physical page is not recorded in the other physical pages corresponding to the specific logical page; and determining that a valid data of the specific logical page is written in the first physical page.