Patent ID: 7243189

Claim:
A data processing system that is connected to a communication device, comprising: at least one computer; a program storage area that stores at least one computer program that is read by the at least one computer; a storage device that comprises a plurality of extents constituting subareas that are able to store data; and an attribute storage area for storing a plurality of access control attributes corresponding with the plurality of extents, wherein the access control attributes corresponding with the extents are access control attributes of a type that is selected from among a plurality of types of access control attributes; the plurality of types of access control attributes do not include an access control attribute signifying read prohibition but include an access control attribute signifying write permission, an access control attribute signifying read permission, and an access control attribute signifying write prohibition; and the at least one computer that reads the at least one computer program retrieves, when a write request is received from a communication device that transmits write target data and the write request, an access control attribute of a write-destination extent according to the write request from among the plurality of access control attributes, judges whether the access control attribute thus retrieved is an access control attribute signifying write prohibition, and controls whether the write target data is written to the write destination extent in accordance with the result of the judgment; and, when a read request for read target data is received from a communication device that transmits the read request, reads the read target data from a read source extent without retrieving the access control attribute of the read source extent according to the read request from among the plurality of access control attributes.