| 摘要 |
PURPOSE:To detect changing to data in a short time with a certain extent of high accuracy by allocating a checking area to at least a part of the continuous memory space and executing equally the checking to all memory elements for a memory block covered by using one memory element. CONSTITUTION:Before transferring to a back-up condition, the checking sum of areas 11a-1na which are a part of a memory area and an access is executed to all memory elements is calculated and the value is stored into a checking sum exclusive-use checking area. After transferring from the condition of back-up to the condition of ordinary action, the checking sum is obtained by the same method again, and when the value is coincident with the preserved checking sum value, all stored data stored in a memory system 1 are decided to be approximately correctly held. Thus, the changing to data in the memory system 1 can be detected in a short time and with a certain extent of high accuracy. |
