Processing of data to perform system changes in an input/output processing system

• US 8,214,562 B2
• Filed: 02/14/2008
• Issued: 07/03/2012
• Est. Priority Date: 02/14/2008
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Ricci, Louis W., Bendyk, Mark P., Carlson, Scott M., Casper, Daniel F., Flanagan, John R., Hathorn, Roger G., Huang, Catherine C., Kalos, Matthew J., Sittmann, Gustav E., Yudenfriend, Harry M., Craig, Matthew R., Holley, Bret W.
• Primary Examiner(s): Peyton, Tammara
• Assistant Examiner(s): YU, HENRY W
• Application Number:
  US12/031,042
• Publication Number:
  US 20090210561A1
• Time in Patent Office: 1,601 Days
• Field of Search: None
• US Class Current: 710/59
• CPC Class Codes: G06F 13/122 where hardware performs an I/O function other than control of data transfer

Abstract

A computer program product, an apparatus, and a method for processing communications between a target and an initiator an input/output processing system are provided. The computer program product includes a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method. The method includes: sending a message from the initiator to the target, the message requesting suspension of input/output operations between the initiator and the target for a period of time, the period of time being defined by the message; responsive to the message, suspending input/output operation messages for the period of time; performing a system change comprising at least one of: at least one update, a computer program installation, a recovery, and a change in operating parameters; and initiating new input/output operations after at least one of: expiration of the period of time and initiation of new input/output operations by the initiator.

Claims

1. A computer program product for processing communications between an initiator unit in network communication with a target unit in an input/output processing system, comprising a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising:

responsive to a communication determining that a selected protocol is supported by the initiator unit and the target unit, the selected protocol supporting suspension of input/output (I/O) operations, receiving by the target unit, a network message from the initiator unit, the network message requesting suspension of input/output operations between the initiator and the target for a period of time, the period of time being defined by the network message, the target unit and the initiator unit selected from one of a channel subsystem of a host computer system and a control unit capable of controlling an input/output (I/O) device;

responsive to the network message being received, suspending transmission of input/output operations to the initiator unit by the target unit for the defined period of time; and

responsive to expiration of the period of time, resuming transmission of input/output operations by the target unit.

2. The computer program product of claim 1, wherein the method further comprises, during the period of time, performing a system change consisting of at least one of an update, a computer program installation, a recovery operation, or a change in operating parameters.

3. The computer program product of claim 2, wherein the computer program installation is a firmware installation performed by a host computer system.

4. The computer program product of claim 2, wherein the change in operating parameters comprises a change between a first operating mode and a second operating mode of at least one of the target unit and the initiator unit.

5. The computer program product of claim 4, wherein the first operating mode uses a first protocol configured to support Channel Command Words (CCW), and the second operating mode uses a second protocol configured to support Transport Control Words (TCW).

6. The computer program product of claim 2, wherein the update is at least one of a code update and a code reload.

7. The computer program product of claim 2, wherein one of the target unit and the initiator unit is a channel subsystem of a host computer system, and another of the target unit and the initiator unit is a control unit capable of commanding and determining a status of an I/O device.

8. The computer program product of claim 7, wherein the recovery is a control unit recovery.

9. The computer program product of claim 2, wherein the network message is a Process Log-out (PRLO) message.

10. The computer program product of claim 9, wherein the initiator unit, prior to sending the PRLO message, performs at least one of:

sending at least one busy signal to the channel subsystem in response to at least one request for execution of an input/output operation, completing pending input/output operations, and terminating pending input/output operations.

11. The computer program product of claim 9, further comprising initiating a Process Log-in (PRLI) message after performing the system change.

12. The computer program product of claim 11, wherein initiating the PRLI message comprises:

sending an identification message from the target unit to the initiator unit to determine whether the initiator unit supports a PRLI/PRLO protocol; and

responsive to receiving an identification message response indicating that the initiator unit supports the PRLI/PRLO protocol, sending the PRLI message to the initiator unit.

24. The computer program product of claim 1, wherein the method further comprises the step of resuming transmission of input/output operations by the target unit responsive to a message from the initiator unit sent during the period of time.

27. The computer program product of claim 1, wherein the selected protocol is selected from at least one of a first protocol configured to support Channel Command Words (CCW) and a second protocol configured to support Transport Control Words (TCW).

13. An apparatus for processing communications in an input/output processing system, comprising:

a target unit in network communication with an initiator unit, the apparatus configured to perform;

responsive to a communication determining that a selected protocol is supported by the initiator unit and the target unit, the selected protocol supporting suspension of input/output (I/O) operations, receiving by the target unit, a network message from the initiator unit, the network message requesting suspension of input/output operations between the initiator and the target for a period of time, the period of time being defined by the network message, the target unit and the initiator unit selected from one of a channel subsystem of a host computer system and a control unit capable of controlling an input/output (I/O) device;

responsive to the network message being received, suspending transmission of input/output operations to the initiator unit by the target unit for the defined period of time; and

responsive to expiration of the period of time, resuming transmission of input/output operations by the target unit.

14. The apparatus of claim 13, wherein the apparatus further performs, during the period of time, a system change consisting of at least one of an update, a computer program installation, a recovery operation, or a change in operating parameters.

15. The apparatus of claim 14, wherein the computer program installation is a firmware installation performed by a host computer system.

16. The apparatus of claim 14, wherein the change in operating parameters comprises a change between a first operating mode and a second operating mode of at least one of the target unit and the initiator unit.

17. The apparatus of claim 14, wherein one of the target unit and the initiator unit is a channel subsystem of a host computer system, and another of the target unit and the initiator unit is a control unit capable of commanding and determining a status of an I/O device.

18. The apparatus of claim 14, wherein the network message is a Process Log-out (PRLO) message.

19. The apparatus of claim 14, further comprising initiating a Process Log-in (PRLI) message to establish the system change.

25. The apparatus of claim 13, wherein the apparatus is configured to further perform the step of resuming transmission of input/output operations by the target unit responsive to a message from the initiator unit sent during the period of time.

28. The apparatus of claim 13, wherein the selected protocol is selected from at least one of a first protocol configured to support Channel Command Words (CCW) and a second protocol configured to support Transport Control Words (TCW).

20. A method of processing communications between an initiator unit in network communication with a target unit in an input/output processing system, the method comprising:

responsive to a communication determining that a selected protocol is supported by the initiator unit and the target unit, the selected protocol supporting suspension of input/output (I/O) operations, receiving by the target unit, a network message from the initiator unit, the network message requesting suspension of input/output operations between the initiator and the target for a period of time, the period of time being defined by the network message, the target unit and the initiator unit selected from one of a channel subsystem of a host computer system and a control unit capable of controlling an input/output (I/O) device;

responsive to the network message being received, suspending transmission of input/output operations to the initiator unit by the target unit for the defined period of time; and

responsive to expiration of the period of time, resuming transmission of input/output operations by the target unit.

21. The method of claim 20, further comprising, during the period of time, performing a system change consisting of at least one of an update, a computer program installation, a recovery operation, or a change in operating parameters.

22. The method of claim 21, wherein one of the target unit and the initiator unit is a channel subsystem of a host computer system, and another of the target unit and the initiator unit is a control unit capable of commanding and determining a status of an I/O device.

23. The method of claim 21, wherein the network message is a Process Log-out (PRLO) message.

26. The method of claim 20, further comprising the step of resuming transmission of input/output operations by the target unit responsive to a message from the initiator unit sent during the period of time.

29. The method of claim 20, wherein the selected protocol is selected from at least one of a first protocol configured to support Channel Command Words (CCW) and a second protocol configured to support Transport Control Words (TCW).