A data processing system having a channel processing device provided with an input/output device which requires input/output interrupt. The channel processing device responding to a request for input/output interrupt, propagating the request for input/output interrupt to a central processing unit, and reporting the state of the input/output device to the central processing unit. The channel processing device includes an interrupt detecting circuit which detects the request for input/output interrupt sent from the input/output device to the channel processing device, a status information detecting circuit which detects whether the status information sent from the input/output device to the channel processing unit together with the request for input output interrupt is a predetermined specified value, and a counting circuit which counts a predetermined constant time when the status information detecting circuit detects the predetermined specific value so that the request for input/output interrupt is sent to the central processing unit after the counting means counts the constant time.
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