The system stores a storage address ADK1 of a page table element PEK1 that was being processed when a bus reset occurred, of page table elements of a page table specified by an ORB1. The system then reads out a storage address ADK2 of a page table element PEK2 having the same element number as PEK1, of page table elements of an ORB2 after the bus reset occurs, and restarts data transfer when ADK1 and ADK2 are the same. When the page table is absent, addresses DAD1 and DAD2 that are specified directly by the ORB1 and the ORB2 are compared. When data transfer is not be restarted but a command CMD1 of the ORB1 has already been issued to a device, the CMD1 is aborted.