Abstract: According to one embodiment, a manufacturing method of a magnetic disk device including a magnetic disk that stores information, and two or more control devices is provided. The method includes acquiring power consumption of each of a plurality of control devices to be able to be included in the magnetic disk device; and selecting a combination of two or more control devices to reduce variation in total power consumption, on the basis of the acquired power consumption.

Abstract: According to one embodiment, a chien search device includes n operation units configured to perform exclusive-OR operations, for each of the coefficients. Further, the chien search device includes first register configured to hold operation results of a highest order operation unit, for each of the coefficients. Furthermore, the chien search device includes exclusive-OR operation unit configured to perform exclusive-OR operations of the results of the first exclusive-OR operations of the highest order operation unit, for each of the coefficients. Moreover, the chien search device includes second register configured to hold operation results of the exclusive-OR operation unit, for each of the coefficients. The respective operation units reduce the number of stages of exclusive-OR operations by using the second register values.

Abstract: According to one embodiment, a chien search device includes n operation units configured to perform exclusive-OR operations, for each coefficient. Further, the chien search device includes first register configured to hold operation results of the highest order operation unit, for each coefficient. Furthermore, the chien search device includes exclusive-OR operation unit configured to perform exclusive-OR operations of the operation results of the highest order operation unit, for each coefficient. Moreover, the chien search device includes second register configured to hold operation results of the exclusive-OR operation unit, for each coefficient. The respective operation units reduce the number of stages of exclusive-OR operations by using the second register values, which are obtained from the second register, and perform operations.