| 摘要 |
PROBLEM TO BE SOLVED: To more accurately judge the propriety of use of a physical block based on the position of a memory cell in which an error is caused and error correcting capability, in the case of controlling defect of a flash memory. SOLUTION: Error control units 23a, 23b storing physical occurrence position information of an error caused at the time of read-out of data are prepared at a redundant part of a physical page by the number of bits which can be corrected by an error correcting code. When the number of positions being different physically of plural errors caused in the same physical page exceed the number of the prepared error control units 23a, 23b, it is judged as that uncorrectable obstacle is caused. Also, in constitution using a multi-level cell, when the total number of bits included in a memory cell corresponding to plural errors caused in the same physical page exceed the number of the prepared error control units 23a, 23b, it is judged as that uncorrectable obstacle is caused. |
