1. A method of remapping stored data in a memory system that before said remapping comprises a first set of memory areas in said memory system that contain said data arranged in a first group of physical memory blocks that are each initially accessed by a first set of logical addresses supplied to said memory system, and that after said remapping comprises a second set of memory areas in said memory system that contain said data in a second group of physical memory blocks that are accessed by said first set of logical addresses, comprising the steps of: recording a first correspondence table that provides a means to relate said first set of logical addresses to said first group of physical memory blocks in said memory system; recording a second correspondence table that provides a means to relate a second set of logical addresses to said memory areas of both said first and second groups of physical memory blocks; removing selected physical memory blocks from said first group of physical memory blocks; adding selected physical memory blocks to form said second group of physical memory blocks; recording a third correspondence table that provides a means to relate said first set of logical addresses to said second group of physical memory blocks; mapping the physical addresses of said first group of physical memory blocks into a first map that records the relationship of said physical addresses of said first group of physical memory blocks with respect to logical addresses from said second correspondence table prior to recording said third correspondence table; mapping the physical addresses of said second group of physical memory blocks into a second map that records the relationship of said physical addresses of said second group of physical memory blocks with respect to logical addresses selected from said second correspondence table prior to recording said third correspondence table; and utilizing said first and second maps to perform said removing and said adding of physical memory blocks.