A manager transmits an I/O bus signal to an I/O bus manager in a computer at a predetermined point of time to inform the I/O bus manager of occurrence of an I/O bus fault. The I/O bus manager initializes an I/O bus and then informs a CPU in the computer of the I/O bus fault as an interruption to be processed by an OS operated by the CPU, whereby the OS can acquire the fault information after the interruption even in the case where an I/O bus fault occurs.