Patent ID: 7464188

Claim:
A computer coupled to a storage apparatus via a network, comprising: an I/O processing unit which issues an I/O request to the storage apparatus; an I/O command issuing unit which is coupled to the network and which receives said I/O request from the I/O processing unit and transmits said I/O request to the storage apparatus via the network; wherein: the I/O processing unit inputs a predetermined program identifier and a request address, generates, with a first function, one value to be used as a new address including said program identifier, and issues said I/O request using the new address, the I/O command issuing unit manages a table associating at least one said program identifier, at least one logical volume existing in said storage apparatus and at least one network address with each other, if said I/O request is an I/O request issued to one said logical volume existing in said storage apparatus that is prescribed to be a protected logical volume, a second function which receives as one input value said new request address and generates, in an operation inverse to that of said first function, said original request address and said program identifier as two output values, said table is searched for said at least one network address associated with said generated program identifier and said at least one logical volume indicated by said generated original request address, and a communication with said storage apparatus is carried out by using said at least one network address as an address of a transmission originator in order to issue an I/O command using said original request address.