Patent ID: 7783922

Claim:
A storage controller which inputs/outputs data to/from a storage device in accordance with a request from a computer, comprising: a check data setting unit, which creates a first check data and second check data on the basis of a first data, and which associates the first check data with the first data and stores the associated first check data in a first storage area in which the first data is stored, and associates the second check data with a second data, which is associated to the first data, and stores the associated second check data in a second storage area; and a checking unit which, if the first data is read out from the first storage area, checks whether or not the first check data read out from the first storage area matches the second check data read out from the second storage area, and which, if the first check data matches the second check data, determines that the first data is correctly read out from the first storage area, and if the first check data and the second check data do not match, detects an occurrence of a failure, wherein the first check data and the second check data respectively comprise update sequence information, which shows an update sequence of the first data stored in the first storage area, and if the first check data and the second check data do not match, the checking unit compares the update sequence information inside the first check data with the update sequence information inside the second check data, determines whether one of the first data and the second date is older than the other, and determines that older data is incorrect data.