| 摘要 |
PROBLEM TO BE SOLVED: To promptly execute data rewriting processing.SOLUTION: An update difference data creation device 20 executes: a step for, when an S byte of small data capacity and an L byte of large data capacity are available as block sizes, calculating a block quantity BN_S in update difference data when the block size is set at the S byte, and a block quantity BN_L in the update difference data when the block size is set at the L byte; a step for extracting disparity data on an S-byte basis when a formula, BN_S×(T_se+(T_bp×S/WS))<BN_L×(T_be+(T_bp×L/WS)), holds; and a step for creating the update difference data. BN_S represents the block quantity in the update difference data when the block size is set at the S byte, BN_L represents the block quantity in the update difference data when the block size is set at the L byte, T_se represents S-byte data erasing time of a flash memory, T_be represents L-byte data erasing time of the flash memory, T_bp represents per-word data writing time of the flash memory, and WS represents a per-word byte quantity. |
