Patent ID: 7302606

Claim:
A fault tolerant control method for recovery of a fault in a storage apparatus that includes a channel connection system for connection to a host apparatus, a channel adapter for receiving a command from said host apparatus through said channel connection system, another channel connection system for connection to said host apparatus, another channel adapter for receiving a command from said host apparatus through said another channel connection system, a cache memory, connected to said channel adapter, for temporarily storing data to be sent to said host apparatus, another cache memory, connected to said another channel adapter, for temporarily storing data to be sent to said host apparatus, a shared memory, connected to said channel adapter, for storing data to control said data stored in said cache memory, another shared memory, connected to said another channel adapter, for storing data to control said data stored in said another cache memory, and wherein said channel adapter and said shared memory are connected to each other with a first plurality of connecting means, said channel adapter and said another shared memory are connected to each other with a second plurality of connecting means, said another channel adapter and said shared memory are connected to each other with a third plurality of connecting means, and said another channel adapter and said another shared memory are connected to each other with a fourth plurality of connecting means, comprising the steps of, if a fault occurs in access from said channel adapter or said another channel adapter to said shared memory or said another shared memory of said storage apparatus: accessing said shared memory or said another shared memory by use of whichever of said connecting means that was not used when said fault was generated; determining a fault location from a result of the accessing step; and isolating said fault location.