Patent ID: 7594062

Claim:
A method for managing a flash memory in which a mapping area, a data area and an alternative area are arranged sequentially therein, the method comprising: if changing of data of a data block recorded at an original address in the data area is requested, recording the data block having changed data in the alternative area and recording mapping information representing an address of the data block recorded in the alternative area in the mapping area; and if changing of data of the data block recorded in the alternative area is requested, recording a data block having changed data at the original address in the data area and deleting the mapping information representing the address of the data block recorded in the alternative area from the mapping area, wherein, if the mapping information on the data block exists in the mapping area, data is read from the data block in the alternative area, and if the mapping information on the data block does not exist in the mapping area, data is read from the data block at the original address in the data area.