| 摘要 |
PURPOSE:To recognize accurately abnormality of computers due to abnormal factors of not only hardware but also software, by providing a shared memory where operation states of respective computers are stored cyclically. CONSTITUTION:An operation state transition diagram for dual operation is stored in CPUs 1 and 2, and the operation state of its own system is stored in a shared memory assigned to respective systems cyclically. For the purpose of preventing both computers from destructing shared memory areas of systems of each other, read and write are permitted for the shared memory area of its own system, and only read is permitted for the shared memory area of the other system. CPUs 1 and 2 output calculation results to a dual system monitor device DSC, and the DSC compares and collates calculation results and outputs calculation results to a control object in case of coincidence. In case of discordance, abnormality is reported to CPUs of both systems, and each CPU receives this report to diagnose the system. |
