| 摘要 |
PURPOSE:To practically prevent data from being erased even when a memory error whose automatic correction is impossible is generated by checking bit information, and when the bit information is a previously determined value, reading out data from a data saving magnetic disk device and storing the read data in a data storage part. CONSTITUTION:A main control part 13 receives a data updating command from a master device, updates data existing in an address specified by the command and sets up bit information indicating the updating in the data storage part 14. If an uncorrectable reading error is generated in the storage part 14 at the time of receiving a read command from the master device, the main control part 13 checks the bit information, and when the bit information is the previously determined value, reads out data existing in the address specified by the read command from an auxiliary storage device and stores the read data in the storage part 14 so as to transfer the stored data to the master device. Thereby even when a memory error whose automatic correction is impossible is generated, data can be practically prevented from being erased. |
