Patent ID: 8683001

Claim:
A computer system comprising: a storage device having a real volume on which data is stored; and a first switch that is connected to a host computer via a second switch, the first switch also connected to the storage device via a third switch, wherein the storage device includes: the real volume being associated with a virtual volume of a virtual storage configured in the first switch and provided to the host computer; and a port used by the host computer to access the real volume via the first switch, wherein the first switch includes: a plurality of port processors for sending/receiving data; a memory having a program stored therein; and a processing module for executing the program, wherein the memory stores: a port ID of the storage device; first information indicating whether or not the storage device has a port ID that is equivalent to a port ID of the virtual storage corresponding to the storage device; and second information indicating one or more attributes of a virtual process, the first and second information being associated with each other, wherein the program includes: a first process, when receiving an inquiry request concerning the storage device from the host computer, that judges whether or not the inquiry request is for the virtual storage based on the second information; a second process which, if the inquiry request is for the virtual storage, judges whether or not the port ID of the virtual storage is equivalent to the port ID of the storage device corresponding to the virtual storage based on the first information; and a third process which, if the port IDs are equivalent, sends an inquiry rejection to the host computer.