DISK CONTROLLER

PROBLEM TO BE SOLVED: To perform the check code conversion of data stored in a disk device while permitting data access to the disk device during system operation concerning a disk controller having a function for converting an old check code into a new check code. SOLUTION: This disk controller 10 is provided with a check code conversion part 12 having a decision means for deciding whether or not a check code attached to data read from a disk device is an old check code or a new check code; a conversion means for converting the old check code into the new check code when the check code added to the read data is the old check code; and a means for writing the data to which the new check code is added in the disk device. The check code conversion part 12 is started as background processing or when the read request of data is made from a host device. COPYRIGHT: (C)2007,JPO&INPIT