Patent ID: 7373465

Claim:
A data processing system, which comprises a host processing apparatus, and a storage subsystem which is communicatively connected to said host processing apparatus and which has a plurality of logical devices for storing data, wherein: said host processing apparatus has a channel unit for notifying access requests for the respective logical devices to said storage subsystem, said storage subsystem has a control processor which controls access processing for the respective logical devices requested by said access request, in response to said access request notified from said host processing apparatus, when an access request is generated for a certain logical device, said channel unit of said host processing apparatus creates one or more channel command words corresponding to said access request, sets logical device identifying information for identifying said certain logical device in a first field, which size is configured as larger than a predetermined logical device address data size to accommodate a plurality of logical device address data therein, in at least one of said channel command words, creates one access request frame of a prescribed structure for each of said at least one channel command word, sets said at least one channel command word in a second field within said frame, and then sends said frame to said storage subsystem, and said control processor of said storage subsystem receives said frame sent from said host processing apparatus, receives said channel command word from said second field of said received frame, acquires said logical device identifying information from said first field of at least one of said received channel command words, specifies which logical device is to be accessed based on said acquired logical device identifying information, and then controls access processing for said certain logical device in accordance with said received channel command word.