Input/output device and method of setting up identification information in input/output device

A method of setting up identification information in an input/output device comprising a plurality of device enclosures, units that are mounted on respective ones of said plurality of device enclosures, a table indicating a correspondence between an access object device, specified by an external device, and a corresponding unit, of said plurality of units, and

• a control unit that logically connects the external device with the corresponding unit, based on said table, wherein said method comprises:
• assigning, at power-on of the input/output device, to each of said device enclosures corresponding device enclosure identification information that does not overlap with device enclosure identification information assigned to another device enclosure;
• assigning a unique slot identification information for each of said device enclosures based on the assigned corresponding device enclosure identification information;
• assigning to each unit, mounted on one of said plurality of device enclosures, corresponding slot identification information based on the assigning the unique slot identification information for each of said device enclosures and that does not overlap with slot identification information assigned to another unit within said device enclosure;
• forming a plurality of single bit sequences each of which is determined by said corresponding slot identification information and said device enclosure identification information;
• and
• forming said table, at power-on of the input/output device after the enclosure identification information is assigned and after the unique slot identification information for each of said device enclosures is assigned, so as to specify a unit, in said input/output device, by respective unit identification information, each being a different one of the plurality of single bit sequences, and does not overlap with respective unit identification information of another unit in the input/output device.