| 摘要 |
<p>PROBLEM TO BE SOLVED: To simply avoid a defect of a device comprising a defective storage element and to make this rewritable semiconductor memory usable. SOLUTION: A memory area consisting of plural memory cells of nonvolatility in the same size is divided into blocks, each consisting of a small aggregation of plural memory cells, and access is performed in this block unit. Address information (starting block addresses) of the 2nd blocks D which are nondefective is stored in the 1st blocks (a), (b), (c) and (d), and defect information about defects of the individual blocks of all the blocks excluding the singular or plural 1st block(s) is stored in the 2nd blocks D. By this constitution, at the time of starting up a system of using the nonvolatile semiconductor memory, the address information of a defect information storage area is extracted by each individual devices concerned, and by retrieving the defect information of the block in this defect information storage area at the time of accessing each block, the defect in this block is avoided to enable the memory to be used.</p> |
