| 摘要 |
A memory system includes a flash memory having a plurality of individually erasable physical blocks, table section for holding the relationship in correspondence between the logical blocks allocated by the allocation section and the physical blocks first counting and managing section for counting and managing write counts of the respective logical blocks, first classifying section for classifying the logical blocks into a plurality of groups on the basis of the respective write counts of the logical blocks, erasure section for erasing data in a physical block allocated to a logical block to produce a free physical block, second counting and managing section for counting and managing the erasure counts of the respective physical blocks, second classifying section for classifying the physical blocks into a plurality of groups on the basis of the respective erasure counts of the physical blocks, control section for allocating the respective logical blocks to the physical blocks; and managing section for managing free physical blocks which are not allocated to any logical blocks, wherein the allocation control section performs an exchanging process as required which comprises the steps of allocating a logical block belonging to a logical block group having a larger write count to a free physical block belonging to a physical block group having a smaller erasure count and allocating a logical block belonging to a logical block group having a smaller write count to a free physical block belonging to a logical block group having a larger erasure count, increasing the service life of the memory system by preventing requests from collecting in a particular sector.
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