RAM value assurance device and RAM value guarantee program

摘要

PROBLEM TO BE SOLVED: To provide a RAM value guarantee device and a RAM value guarantee program that achieve assurance of a storage value of a RAM while controlling a storage capacity of the RAM.SOLUTION: A CPU executes steps of: using an OS to monitor an address shown by a program counter 6; when confirming that the address in the program counter 6 transits from a non-guarantee program area 9 to a guarantee program area 10, comparing data in a guarantee RAM area 12 with data in a backup RAM area 13; and when there is an inconsistency between the data, updating the data in the guarantee RAM area 12 with the data in the backup RAM area 13. A CPU 8 executes steps of: using the OS to monitor the address shown by the program counter 6; when confirming that the address in the program counter 6 transits from an update permission area 10a to an update permission area 10b, permitting update of a RAM_A group backup 13a right before the transition; updating data in the RAM_A group backup 13a with data in a RAM_A group 12a; and prohibiting the update of the RAM_A group backup 13a after the update processing.