PROCESSING OF DATA TO SUSPEND OPERATIONS IN AN INPUT/OUTPUT PROCESSING SYSTEM

• US 20090210564A1
• Filed: 07/29/2008
• Published: 08/20/2009
• Est. Priority Date: 02/14/2008
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Kalos, Matthew J., Yudenfriend, Harry M., Huang, Catherine C., Flanagan, John R., Ricci, Louis W., Carlson, Scott M., Bendyk, Mark P., Hathorn, Roger G., Sittmann, Gustav E., Casper, Daniel F.
• Granted Patent: US 7,856,511 B2
• Time in Patent Office: Days
• US Class Current: 710/6
• CPC Class Codes: G06F 13/124 where hardware is a sequential transfer control unit, e.g. microprocessor, peripheral processor or state-machine

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 between the initiator and 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; and responsive to the message, suspending input/output operation messages for the period of time.

Claims

1. A computer program product for processing communications between a target and an initiator 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:

sending a message between the initiator and 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; and

responsive to the message, suspending input/output operation messages for the period of time.

2. The computer program product of claim 1, wherein one of the target and the initiator is a channel subsystem of a host computer system, and another of the target and the initiator is a control unit capable of commanding and determining a status of an I/O device.

3. The computer program product of claim 2, wherein the message is initiated from the control unit, and the period of time is subject to a maximum period specified in a Process Log-in (PRLI) message sent by the channel.

4. The computer program product of claim 1, wherein the message is a Process Log-out (PRLO) message.

5. The computer program product of claim 1, wherein the message comprises a data setting in a field of the message that defines the period of time.

6. The computer program product of claim 1, wherein suspending comprises at least one of:

terminating input/output operations pending between the initiator and the target, completing input/output operations pending between the initiator and the target, and stopping input/output operation messages during the period of time.

7. The computer program product of claim 1, further comprising initiating new input/output operations after expiration of the period of time.

8. The computer program product of claim 2, wherein the message is initiated from the control unit, and the method further comprises initiating a login procedure between the channel and the control unit after expiration of the period of time.

9. The computer program product of claim 2, wherein the message is initiated from the channel subsystem, and the method further comprises sending unsolicited status messages to the channel subsystem after expiration of the period of time.

10. The computer program product of claim 1, wherein the message is initiated from the initiator, and the target initiates new input/output operations after at least one of:

initiation of new input/output operations by the initiator, and expiration of the period of time.

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

an initiator, and a target in communication with the initiator, the apparatus performing;

sending a message between the initiator and 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; and

responsive to the message, suspending input/output operation messages for the period of time.

12. The apparatus of claim 11, wherein one of the target and the initiator is a channel subsystem of a host computer system, and another of the target and the initiator is a control unit capable of commanding and determining a status of an I/O device.

13. The apparatus of claim 12, wherein the message is initiated from the control unit, and the period of time is subject to a maximum period specified in a Process Log-in (PRLI) message sent by the channel.

14. The apparatus of claim 11, wherein the message is a Process Log-out (PRLO) message.

15. The apparatus of claim 11, wherein suspending comprises at least one of:

terminating input/output operations pending between the initiator and the target, completing input/output operations pending between the initiator and the target, and initiating new input/output operations after expiration of the period of time.

16. The apparatus of claim 12, wherein the message is initiated from the control unit, and the method further comprises initiating a login procedure between the channel and the control unit after expiration of the period of time.

17. The apparatus of claim 12, wherein the message is initiated from the channel subsystem, and the method further comprises sending unsolicited status messages to the channel subsystem after expiration of the period of time.

18. The apparatus of claim 11, wherein the message is initiated from the initiator, and the target initiates new input/output operations after at least one of:

initiation of new input/output operations by the initiator, and expiration of the period of time.

19. A method of processing communications between an initiator and a target in an input/output processing system, the method comprising:

sending a message between the initiator and 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; and

responsive to the message, suspending input/output operation messages for the period of time.

20. The method of claim 19, wherein one of the target and the initiator is a channel subsystem of a host computer system, and another of the target and the initiator is a control unit capable of commanding and determining a status of an I/O device.