Semiconductor disk apparatus having a semiconductor memory for a

Abstract

Each semiconductor memory module is divided into a plurality of access control units, and a service adapter copies the contents of the memory of the semiconductor memory module in which a memory error has occurred, to a spare semiconductor memory module one access control unit at a time. It is thus possible to evacuate the contents of the memory of the semiconductor memory module in which the memory error has occurred without stopping the semiconductor disk apparatus simply by adding the spare semiconductor disk apparatus. Since the copying operation is executed one access control unit at a time, a resource manager can conduct exclusive control also one access control unit at a time. A host apparatus therefore can access an access control unit portion which is not the object of copying even in the process of copying. In other words, the copying operation exerts no deleterious influence on the access of the host apparatus.