Data processing system and method

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 plurality of storage devices that store data;
• a plurality of extents provided in at least one storage device of the plurality of storage devices;
• a cache memory area that temporarily stores data that is exchanged between the storage devices and the communication device;
• a control memory area that stores information for controlling the exchange of the data;
• a first management area that stores a plurality of access control attributes that correspond with the plurality of extents respectively;
• and
• a second management area that stores, for each storage device, information on the existence of a write prohibition extent that indicates whether a write prohibition extent, which is an extent that corresponds with an access control attribute signifying write prohibition, is included in the plurality of extents,
• wherein the first management area exists in the storage device that comprises the plurality of extents;
• the second management area exists in at least one of the cache memory area and the control memory area;
• and
• the at least one computer that reads the at least one computer program:
• judges, when a write request is received from a communication device that transmits write target data and the write request, whether the write prohibition extent exists in a write-destination storage device by accessing the second management area and referencing information on the existence of the write prohibition extent that corresponds with the write-destination storage device according to the write request;
• and,
• when it is judged that the write prohibition extent exists in the write destination storage device, accesses the first management area that is provided in the write destination storage device, retrieves, from among the plurality of access control attributes, an access control attribute that corresponds with the write-destination extent among a plurality of extents provided in the write destination storage device, 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.

A data processing method in which there are a plurality of access control attributes each corresponding with a plurality of extents provided in a storage device, the access control attributes corresponding with the extents being access control attributes of a type that is selected from among a plurality of types of access control attributes and in which 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, comprising the steps of:

• receiving a write request from a host computer that transmits write target data and the write request;
• retrieving an access control attribute of a write destination extent according to the received write request from among a plurality of access control attributes that each correspond with a plurality of extents provided in the storage device;
• judging whether the access control attribute thus retrieved is an access control attribute signifying write prohibition;
• controlling whether the write target data is written to the write destination extent in accordance with the result of the judgment;
• receiving the read request from a host computer that transmits a read request for read target data;
• and
• reading the read target data from a read source extent without retrieving the access control attribute of the read source extent according to the received read request from among the plurality of access control attributes.

A data processing method, where in a plurality of extents provided in at least one storage device of the plurality of storage devices, a cache memory area that temporarily stores data that is exchanged between the storage devices and the communication device, a control memory area that stores information for controlling the exchange of the data, a first management area that stores a plurality of access control attributes that correspond with the plurality of extents respectively, and a second management area that stores, for each storage device, information on the existence of a write prohibition extent that indicates whether a write prohibition extent, which is an extent that corresponds with an access control attribute signifying write prohibition, is included in the plurality of extents, are provided;

• the first management area exists in the storage device that comprises the plurality of extents;
• the second management area exists in at least one of the cache memory area and the control memory area;
• when a write request is received from a communication device that transmits write target data and the write request, a judgment of whether the write prohibition extent exists in a write-destination storage device is performed by accessing the second management area and referencing information on the existence of the write prohibition extent that corresponds with the write-destination storage device according to the write request;
• and,
• when it is judged that the write prohibition extent exists in the write destination storage device, the first management area that is provided in the write destination storage device is accessed, an access control attribute that corresponds with a write-destination extent among a plurality of extents provided in the write destination storage device is retrieved from among the plurality of access control attributes, a judgment of whether the access control attribute thus retrieved is an access control attribute signifying write prohibition is performed, and control of whether the write target data is written to the write destination extent is performed in accordance with the result of the judgment.