Patent ID: 8250318

Claim:
A storage controller coupled to a host computer, comprising: a controller including an additional code length setting unit, a logical sub-block setting unit, and a logical block setting unit; and a plurality of storage devices; wherein the additional code length setting unit sets a length of a guarantee code in accordance with a performance request from the host computer, which includes transaction performance and sequential access performance, the logical sub-block setting unit sets a length of a logical sub-block in which an additional code containing the guarantee code is added to user data, the logical block setting unit creates a logical access block whose length is equal to the integral multiple of the length of a physical sub-block, the additional code length setting unit adds a pad data, whose data amount is a difference between the length of the logical access block and the integral multiple of the length of the logical sub-block, to the logical sub-block, and the controller processes an access to and from the storage devices in the length of the logical access block.