Method of data writing to and data reading from storage device and data storage system

Abstract

Reliability of stored data in a semiconductor storage device such as a flash memory is enhanced. There are provided (n+1) physical storage regions each having m data storage areas and for which data writing, data reading, data erasure, and the like are collectively performed. A sequence of data input from a supervisory host as write data are rearranged, and that sequence of data is split across the n physical storage regions, for storage. Error correction data for the sequence of datato data n split across the respective physical storage regions is stored in another (n+1)th physical storage region as data p. Error correction data pfor data (n+1) to datan, and error correction data pm for data ((m−1)n+1) to data mn are stored in the same manner. When abnormality is present in part or all of the data stored in a second physical storage region, for example, the data in the second physical storage region restored by error correction is stored in an alternative physical storage region, and the data in the second physical storage region are all erased.