Determining the state of an I/O operation
First Claim
1. A computer program product for determining a state of an input/output (I/O) operation in an I/O processing system, comprising:
- a tangible storage medium readable by a processing circuit and storing instructions for executing by the processing circuit for performing a method comprising;
receiving, at a channel subsystem, a request for performing the I/O operation from an I/O operating system, the request having an associated time period for completion of the I/O operation;
responsive to the request, forwarding a transport command control block (TCCB) from the channel subsystem to a control unit controlling an I/O device for executing the I/O operation, the TCCB including at least one device control word (DCW) and the TCCB being obtained by a location identified by a transport control word (TCW);
receiving, at the channel subsystem, an interrogation request from the I/O operating system at a point in time prior to the expiration of the associated time period and absent an indication from the control unit that the I/O operation is completed, the interrogation request for determining the state of the I/O operation, and the point in time within a threshold of the expiration of the associated time period;
responsive to receipt of the interrogation request at the channel subsystem, sending an interrogation command from the channel subsystem to the control unit to determine the state of the I/O operation; and
receiving, at the channel subsystem, a response from the control unit indicating the state of the I/O operation, wherein the response includes information indicating 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.
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Accused Products
Abstract
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.
168 Citations
20 Claims
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1. A computer program product for determining a state of an input/output (I/O) operation in an I/O processing system, comprising:
a tangible storage medium readable by a processing circuit and storing instructions for executing by the processing circuit for performing a method comprising; receiving, at a channel subsystem, a request for performing the I/O operation from an I/O operating system, the request having an associated time period for completion of the I/O operation; responsive to the request, forwarding a transport command control block (TCCB) from the channel subsystem to a control unit controlling an I/O device for executing the I/O operation, the TCCB including at least one device control word (DCW) and the TCCB being obtained by a location identified by a transport control word (TCW); receiving, at the channel subsystem, an interrogation request from the I/O operating system at a point in time prior to the expiration of the associated time period and absent an indication from the control unit that the I/O operation is completed, the interrogation request for determining the state of the I/O operation, and the point in time within a threshold of the expiration of the associated time period; responsive to receipt of the interrogation request at the channel subsystem, sending an interrogation command from the channel subsystem to the control unit to determine the state of the I/O operation; and receiving, at the channel subsystem, a response from the control unit indicating the state of the I/O operation, wherein the response includes information indicating 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. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An apparatus adapted for communicating with a control unit controlling an input/output (I/O) device for executing an I/O operation in an I/O processing system, the apparatus comprising:
a channel subsystem configured to communicate with an I/O operating system and the control unit, the channel subsystem configured to perform a method comprising; receiving a request for performing the I/O operation from the I/O operating system, the request having an associated time period for completion of the I/O operation; responsive to the request, forwarding a transport command control block (TCCB) to the control unit controlling the I/O device for executing the I/O operation, the TCCB including at least one device control word (DCW) and the TCCB being obtained by a location identified by a transport control word (TCW); receiving an interrogation request from the I/O operating system at a point in time prior to the expiration of the associated time period and absent an indication from the control unit that the I/O operation is completed, the interrogation request for determining a state of the I/O operation, and the point in time within a threshold of the expiration of the associated time period; responsive to receipt of the interrogation request, sending an interrogation command to the control unit to determine the state of the I/O operation; and receiving a response from the control unit indicating the state of the I/O operation, wherein the response includes information indicating 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. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A method for determining a state of an input/output (I/O) operation in an I/O processing system, comprising:
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receiving, at a channel subsystem, a request for performing the I/O operation from an I/O operating system, the request having an associated time period for completion of the I/O operation; responsive to the request, forwarding a transport command control block (TCCB) from the channel subsystem to a control unit controlling an I/O device for executing the I/O operation, the TCCB including at least one device control word (DCW) and the TCCB being obtained by a location identified by a transport control word (TCW); receiving, at the channel subsystem, an interrogation request from the I/O operating system at a point in time prior to the expiration of the associated time period and absent an indication from the control unit that the I/O operation is completed, the interrogation request for determining the state of the I/O operation, and the point in time within a threshold of the expiration of the associated time period; responsive to receipt of the interrogation request at the channel subsystem, sending an interrogation command from the channel subsystem to the control unit to determine the state of the I/O operation; and receiving, at the channel subsystem, a response from the control unit indicating the state of the I/O operation, wherein the response includes information indicating 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. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification