DATA MULTIPLYING METHOD, INFORMATION PROCESSOR, AND STORAGE SUBSYSTEM

PROBLEM TO BE SOLVED: To enable data multiplication between a main and a subordinate disk subsystems by remote copying at low investment cost. SOLUTION: The main subsystem 3 and subordinate subsystem 5 perform data multiplication, the main subsystem 3 is connected to a CPU 1 through an interface cable 5, and the subordinate subsystem 5 is connected to the main subsystem 3 through an interface cable 4; and a channel interface control part 10 which controls a standard I/F for the CPU 1 and an IO interface control part 12 which performs writing indication, data transfer, response acceptance, etc., for the subordinate subsystem 5 through the standard I/F by behaving for the subordinate subsystem 5 like the CPU side of the standard I/F are provided on the side of the main subsystem 3, and the subordinate subsystem 5 may be a configuration for general purpose to be equipped with only a channel interface control part 11 for the standard I/F.