| 摘要 |
PURPOSE:To perform high-reliability backup operation while using a low-reliability backup memory, such as a floppy disck, by restoring data by a data memory and the backup memory by turns. CONSTITUTION:According to a constant-time signal from an interval timer 5, etc., a CPU1 generates check sum data at constant intervals of time from the contents of a backup memory 12 which backs up an RAM data memory 3, and it is collated with previously stored check sum data. Then, if a check sum error is detected, data from the memory 3 are transferred via the CPU1 to the memory 12, whose contents are restored to correct data. Because of the system which restores the contents of the backup memory by the data memory, the memory backup device has high reliability even when a floppy disk or the like having relatively low reliability is used as the backup memory. |
