EQUIVALENCE DISCRIMINATING SYSTEM FOR DUPLEX VOLUME

PURPOSE:To discriminate the equivalence of the content of a duplex volume when a system is shut-off in the duplex system of a magnetic disk. CONSTITUTION:The system consists of a duplex input/output starting means 3 which invalidates an equivalence discrimination flag 9 which is corresponded at the time of receiving updation to a duplex volume 5 and which issues duplex output, a duplex input/output terminating means 4 which invalidates the equivalence discrimination flag 9 corresponded at the time of receiving the normal termination of original and auxiliary updation, a duplex volume updation judging means 2 discriminating updation input/output to the duplex volume and a duplex volume non-equivalence informing means 10 which refers to the equivalence discrimination flag 9 and displays a non-equivalent duplex volume. Since the equivalence of the duplex volume can be discriminated even if the system is shut-off, duplex restoration work can be made efficient.