| 摘要 |
PURPOSE:To eliminate the need to copy the contents of a memory to a magnetic disk before the power source of a device is turned OFF and to easily make a recovery from a parity error even if the parity error occurs when data are read out of the memory. CONSTITUTION:Flags in a management table 100 are searched for to easily judge whether or not data in storage areas 101, 102-10n of the memory match data in paired storage area 201, 202-20n on the magnetic disk; when they match each other, the data are read out of the memory as they are, but when not, the data are copied from the storage areas on the magnetic disk to the memory temporarily and read out. When the data are copied, the flags are so set as to indicate the copying and then the data can continuously be read out of the memory unless there is new variation. The data are copied similarly even in the case of parity error occurrence during a read out of the memory, and a recovery from the parity error can be made. |
