Storage apparatus, and control method and control apparatus therefor

A method executed by a computer for controlling write operations to a storage medium, the method comprising:

• receiving second data with which the first data in the storage medium is to be updated;
• determining, upon reception of the second data, whether the received second data coincides with the first data, based on comparison data read out of the storage medium, when no copy of the first data is found in the cache memory;
• and
• determining not to write the second data into the storage medium when the second data is determined to coincide with the first data.

A storage apparatus comprising:

• a storage medium configured to store data;
• and
• a control apparatus configured to control write data operations to the storage medium, the control apparatus comprising
• a cache memory configured to store a temporary copy of first data written in the storage medium, and
• a processor configured to perform a procedure comprising
• receiving second data with which the first data in the storage medium is to be updated,
• determining, upon reception of the second data, whether the received second data coincides with the first data, based on comparison data read out of the storage medium, when no copy of the first data is found in the cache memory, and
• determining not to write the second data into the storage medium when the second data is determined to coincide with the first data.