Patent ID: 7231580

Claim:
An information storage device comprising: one or more semiconductor memories; an information processing part that, according to an operation program, reads data stored in the one or more semiconductor memories, writes data to the one or more semiconductor memories, and performs other operations; and a transfer processing part that, if read data read from the semiconductor memories contains minor a count of which is equal to or less than a predetermined count, corrects the minor errors and transfers the data, and if the read data contains major errors the count of which is more than the predetermined count, transfers the data without correcting the major errors, wherein the transfer processing part comprises: a management data creation part that creates management data used for data corrections from write data transferred from the outside; an error detection part that detects whether the read data contains error locations, based on the read data and the management data created by the management data creation part; and a first data correction and calculation part that, when errors are detected by the error detection part, calculates correction locations and correction data of the read data, and judges whether the read data contains major errors or minor errors, and wherein the information processing part, when the first data correction and calculation part judges that the read data contains minor errors, replaces the read data by the correction data in the correction locations thereof calculated by the first data correction and calculation part, and transfers the corrected data to the outside, and when the first data correction and calculation part judges that the read data contains major errors, transfers the read data to the outside without correcting the read data.