An initiator has logical devices A, B and C. In the directory structure of the config ROM showing the unit structure, instance directories A, B and C are made; initiator unit directories 1, 2, and 3 are made under the respective instance directories A, B and C; and feature directories showing the functions provided by the respective logical devices are made under the initiator unit directories 1, 2, and 3. This structure allows the functions available from the initiator to be shown and allows the available functions to be known to another node such as a target device.