PURPOSE: To improve the performance of an error processing method when an error occurs on an I/O device side in respect to an error processing method by a system provided with a channel device and 1st and 2nd intermediate devices for setting up the remote distance of an I/O interface for connecting plural I/O devices.

CONSTITUTION: The 2nd intermediate device 31 detecting an error generated on the I/O device side executes selective reset operation for selectively resetting an I/O device 2 held at an error state prior to the operation of the channel device 1, inputs information indicating the generation of the error to a queue generated from the 1st intermediate device 30, and then connects the I/O device 2 to the channel device 1 by RQI connection issued based upon a connection request from the device 2 to inform the generation of the error to the device 1 by 'disconnect in' (DISCIN) indicating the disconnection of the current connected state instead of the report of 'status in' (STI).