COMPUTER COMMAND AND RESPONSE FOR DETERMINING THE STATE OF AN I/O OPERATION

摘要

A state of an input/output (I/O) operation in an I/O processing system is determined. A request for performing the I/O operation is received from an I/O operating system at a channel subsystem and forwarded to a control unit controlling an I/O device for executing the I/O operation. After a predetermined amount of time passes without receiving indication from the control unit that the I/O operation is completed, an interrogation request is received at the channel subsystem from the I/O operating system for determining the state of the I/O operation. An interrogation command is sent from the channel subsystem to the control unit. A response is received from the control unit, the response indicates a state of the I/O device executing the I/O operation, a state of the control unit controlling the I/O device executing the I/O operation, and the state of the I/O operation being executed.