There is provided a method of making a high-melting metal powder which has high purity and excellent formability and, particularly, of a metal powder of spherical particles made of Ta, Ru, etc. The storage area network comprises a plurality of host data processors coupled to a virtualization engine, which is coupled to a plurality of physical storage media. A gain control function generation information modifying circuit 104 modifies gain control function generation information according to the cutoff amount.