Patent ID: 8711627

Claim:
A block selection method for a flash memory, comprising: dividing a flash memory into a plurality of great block groups, wherein each of the great block groups comprise a first number of blocks; dividing each of the great block groups into a plurality of block groups, wherein each of the block groups comprise a second number of blocks; recording scores corresponding to the blocks of the flash memory in a score table; recording a plurality of first extreme values of the scores corresponding to the blocks of each of the block groups, a plurality of second extreme values of the scores corresponding to the blocks of each of the great block groups, and a total extreme value of the scores corresponding to the blocks of the flash memory in an extreme value table; when the score of a target block selected from the blocks of the flash memory has been amended, comparing the amended score of the target block with the first extreme value corresponding to the block group comprising the target block to determine whether the first extreme value corresponding to the block group comprising the target block has been amended to be equal to the score of the target block, comparing the amended score of the target block with the second extreme value corresponding to the great block group comprising the target block to determine whether the second extreme value corresponding to the great block group comprising the target block has been amended to be equal to the score of the target block, and comparing the amended score of the target block with the total extreme value to determine whether the total extreme value has been amended to be equal to the score of the target block; and determining a victim block from the blocks of the flash memory according to the extreme value table.