Worm guarantee storage device employing block write inhibition information

A disk array system which stores data accessed by the computer, the disk array system comprising:

• a plurality of disk drives that store the data;
• a cache memory that temporarily stores the data which is transferred between the computer and the plurality of disk drives;
• and
• a control unit that controls an input/output of the data to/from the cache memory;
• wherein, when receiving a data write request from the computer, the control unit:
• refers to write inhibition information indicating whether a writing to a region divided into access unit lengths of the disk drive designated by the write request is possible, from the cache memory;
• and
• judges whether the writing of write data from the computer is possible, by using the write inhibition information;
• and
• wherein the control unit:
• divides the write data transferred from the computer into the predetermined data lengths;
• and
• stores the write inhibition information in a bitmap corresponding to each piece of data divided into the predetermined data lengths and stored in the cache memory.

A disk array system which stores data accessed by the computer, the disk array system comprising:

• a plurality of disk drives that store the data;
• a cache memory that temporarily stores the data which is transferred between the computer and the plurality of disk drives;
• and
• a control unit that controls an input/output of the data to/from the cache memory;
• wherein, when receiving a data write request from the computer, the control unit:
• refers to write inhibition information indicating whether a writing to a region divided into access unit lengths of the disk drive designated by the write request is possible, from the cache memory;
• and
• judges whether the writing of write data from the computer is possible, by using the write inhibition information;
• and
• wherein the control unit:
• divides the write data transferred from the computer into the predetermined data lengths;
• stores the write inhibition information in a bitmap corresponding to each piece of data divided into the predetermined data lengths and stored in the cache memory;
• compares a ratio of used write inhibition information and unused write inhibition information of the bitmap with a predetermined value;
• and
• if the ratio of the used write inhibition information and the unused write inhibition information is equal to or greater than the predetermined value, restructures a region in which the used write inhibition information is included to increase the ratio of the unused write inhibition information and the used write inhibition information.