Patent ID: 7032128

Claim:
A method of changing over in a multiplex system including a first computer and a second computer each having a processing unit for monitoring a fault of said first computer and said second computer by transmitting and receiving a heart beat signal to and from each other, and a disk control unit for controlling a disk enabled a setting of an access right to one of said first and second computers, comprising the steps of: determining whether or not a detection result of said heart beat signal transmitted from said first computer satisfies a predetermined condition by said second computer; transmitting a request for monitoring said first computer to said disk control unit in accordance with the determination result; transmitting a request for transmitting said heart beat signal to said first computer by said disk control unit, when receiving said monitoring request; determining whether or not a detection result of said heart beat signal transmitted from said first computer satisfies a predetermined condition by said disk control unit; and when satisfying the predetermined condition, releasing an access right to said disk of said first computer by said disk control unit.