CONTROLLER OF NONVOLATILE MEMORY UNIT, MEMORY SYSTEM HAVING THE SAME CONTROLLER, AND CONTROL METHOD FOR NONVOLATILE MEMORY UNIT

摘要

PROBLEM TO BE SOLVED: To keep a nonvolatile memory unit normal even if write error occurs for some reason while the nonvolatile memory unit is written. SOLUTION: At the end of writing data to the nonvolatile memory unit 13, a controller 11 writes new management information (a conversion table 131 and an assignment table 132) reflecting the written data to an area different from the area of a memory unit 13 where the latest management information so far is saved and then writes an old management information flag while making it corresponding to the latest management information so far. Further, the controller 11 retrieves the latest normal management information from the memory unit 13 when the memory system 10 is initialized and restores the latest management information according to the normal old management information made to correspond to the old management information flag if the latest normal management information can not be found.