INPUT/OUTPUT INTERRUPT SYSTEM

摘要

The system includes a CPU and an input/output device which requires an input/output interrupt. A channel progressing circuit responds to a request for input/output interrupt, propagates the request to the CPU and reports the state of the input/output device to the CPU. The channel progressing cirucit includes interrupt detecting circuitry which senses the request for input/output interrupt. Status information detecting circuitry senses whether status information sent from the input/output device to the channel progressing unit together with the request for input/output interrupt has a predetermined value. A counting device counts a predetermined constant time when the status information detecting circuitry senses the predetermined value.