BI-DIRECTIONAL DATA TRANSFER WITHIN A SINGLE I/O OPERATION

• US 20090210581A1
• Filed: 02/14/2008
• 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., Huang, Catherine C., Flanagan, John R., Sittmann, Gustav E., Njoku, Ugochukwu C., Casper, Daniel F., Riedy, Dale F.
• Granted Patent: US 7,941,570 B2
• Time in Patent Office: Days
• US Class Current: 710/33
• CPC Class Codes: G06F 13/126 and has means for transferring I/O instructions and statuses between control unit and main processor
• CPC Class Codes: G06F 3/0613 in relation to throughput
• CPC Class Codes: G06F 3/0659 Command handling arrangements, e.g. command buffers, queues, command scheduling
• CPC Class Codes: G06F 3/0673 Single storage device

Abstract

An article of manufacture, apparatus, and a method for facilitating input/output (I/O) processing for an I/O operation at a host computer system configured for communication with a control unit. The method includes the host computer system obtaining a transport command word (TCW) for an I/O operation having both input and output data. The TCW specifies a location of the output data and a location for storing the input data. The host computer system forwards the I/O operation to the control unit for execution. The host computer system gathers the output data responsive to the location of the output data specified by the TCW, and then forwards the output data to the control unit for use in the execution of the I/O operation. The host computer system receives the input data from the control unit and stores the input data at the location specified by the TCW.

Claims

1. A computer program product for facilitating input/output (I/O) processing for an I/O operation at a host computer system configured for communication with a control unit, the computer program product comprising:

a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising;

the host computer system obtaining a transport command word (TCW) for an I/O operation having both input and output data, the TCW specifying a location of the output data, and a location for storing the input data;

the host computer system forwarding the I/O operation to the control unit for execution;

the host computer system gathering the output data responsive to the location of the output data specified by the TCW;

the host computer system forwarding the output data to the control unit for use in the execution of the I/O operation;

the host computer system receiving the input data from the control unit; and

the host computer system storing the input data at the location specified by the TCW for storing the input data.

2. The computer program product of claim 1 wherein the TCW further specifies a size of the output data, and the gathering the output data is further responsive to the size of the output data.

3. The computer program product of claim 1 wherein the I/O operation includes one or more commands to be executed by the I/O operation.

4. The computer program product of claim 1 wherein one or both of the location of the output data and the location for storing the input data are direct addresses.

5. The computer program product of claim 1 wherein one or both of the location of the output data and the location for storing the input data are indirect addresses.

6. The computer program product of claim 1 wherein the host computer system includes an I/O processing system and the method is performed by the I/O processing system.

7. The computer program product of claim 1 wherein the host computer system includes a channel subsystem and the method is performed by the channel subsystem.

8. The computer program product of claim 1 wherein the TCW is obtained from a host operating system.

9. A host computer system for providing bi-directional data transfer within a single I/O operation, comprising:

a host computer I/O subsystem comprising a channel adapter, the channel adapter in communication with a control unit, the host I/O subsystem performing a method comprising;

obtaining a TCW for an I/O operation having both input and output data, the TCW specifying a location of the output data and a location for storing the input data;

gathering the output data responsive to the location of the output data specified by the TCW;

forwarding the I/O operation and the output data and to the control unit for execution;

receiving the input data from the control unit; and

storing the input data at the location specified by the TCW for storing the input data.

10. The apparatus of claim 9 wherein the TCW further specifies a size of the output data, and the gathering the output data is further responsive to the size of the output data.

11. The apparatus of claim 9 wherein the I/O operation includes one or more commands to be executed by the I/O operation.

12. The apparatus of claim 9 wherein one or both of the location of the output data and the location for storing the input data are direct addresses.

13. The apparatus of claim 9 wherein one or both of the location of the output data and the location for storing the input data are indirect addresses.

14. The apparatus of claim 9 wherein the TCW is obtained from a host operating system.

15. A method for facilitating I/O processing for an I/O operation at a host computer system configured for communication with a control unit, the method comprising:

obtaining a TCW for an I/O operation having both input and output data, the TCW specifying a location of the output data and a location for storing the input data;

gathering the output data responsive to the location of the output data specified by the TCW;

forwarding the I/O operation and the output data to the control unit for execution;

receiving the input data from the control unit; and

storing the input data at the location specified by the TCW for storing the input data.

16. The method of claim 15 wherein the TCW further specifies a size of the output data, and the gathering the output data is further responsive to the size of the output data.

17. The method of claim 15 wherein the I/O operation includes one or more commands to be executed by the I/O operation.

18. The method of claim 15 wherein one or both of the location of the output data and the location for storing the input data are direct addresses.

19. The method of claim 15 wherein one or both of the location of the output data and the location for storing the input data are indirect addresses.

20. The method of claim 15 wherein the host computer system includes an I/O processing system and the method is performed by the I/O processing system.

21. The method of claim 15 wherein the host computer system includes a channel subsystem and the method is performed by the channel subsystem.

22. The method of claim 15 wherein the TCW is obtained from a host operating system.