US Patent 7877668 Memory access system

When a host system outputs a read command to a memory controller, it measures a load count of a memory area on which a read access load is imposed. Then, when the host system judges that the load count of a memory area reaches a predetermined count, it causes the memory controller to perform an error detection on the memory area. Further, when the host system finds that an error occurs in the memory area, it causes the memory controller to perform an error correction on the memory area. This can avoid or reduce unintended rewriting due to repeated readouts.