Asynchronous command support for shared channels for a computer complex having multiple operating systems

• US 5,452,455 A
• Filed: 06/15/1992
• Issued: 09/19/1995
• Est. Priority Date: 06/15/1992
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Cwiakala, Richard, Hollar, David W., Brown, Miriam P., Wyman, Leslie W., Shapley, Charles E., Oakes, Kenneth J., Halma, Marten J., Marron, Assaf, Fredericks, Kenneth J., Hough, Roger E., John, Suzanne M., Mazurowski, James C.
• Primary Examiner(s): Kriess, Kevin A.
• Assistant Examiner(s): BUTLER, DENNIS
• Application Number:
  US07/898,977
• Time in Patent Office: 1,191 Days
• Field of Search: 395/650, 395/700, 395/275
• US Class Current: 713/100
• CPC Class Codes: G06F 13/10 Program control for peripheral devices G06F13/14 - G06F13/42 take precedence

Abstract

This invention involves reconfiguration support for shared I/O resources in a a computer electronic complex (CEC) supporting both shared and unshared I/O channels of the type described and claimed in U.S. patent application Ser. No. 07/898,867 (PO9-92-016) filed on the same day as the subject application and assigned to the same assignee as the subject application. Prior channel subsystem call (CHSC) instructions cannot execute when a channel is to be configured as shareable by plural operating systems in a CEC.

Claims

1. A method of reconfiguring an input/output subsystem shared by a plurality of control programs (OSs) in a computer electronic complex (CEC), each of said programs having a program identifier (IID), said method including the steps of:

providing a sharing set of input/output control blocks, each input/output control block of said sharing set including an input/output resource identifier for an input/output resource and a program identifier;

storing said sharing set of input/output control blocks in said computer electronic complex;

providing a configuration mask for establishing a reconfiguration of said input/output resource, said configuration mask including an image identifier field for identifying each of said plurality of programs;

setting said image identifier field to a state that specifies an image identifier of a program;

accessing said sharing set of input/output control blocks;

setting a field in said sharing set of control blocks that corresponds to said image identifier field that has been set in the previous setting step;

changing association of input/output resources in accordance with said configuration mask in each of said control blocks of said sharing set of input/output control blocks that have a field in the just previous setting step.

2. A method of reconfiguring as I/O subsystem of a computer electronic complex (CEC), as defined in claim 1, including the further step of:

changing a field in the control block of the sharing set to dis-associate the IID of the one field indicated in the configuration mask for the control block of the sharing set to reconfigure the input/output resource from the control program represented by the IID.

3. A method of reconfiguring an I/O subsystem of a computer electronic complex (CEC), as defined in claim 2, including the further step of

aborting the dis-associate operation in the step of claim 2 if the OS associated with the IID has the input/output resource currently in use.

4. A method of reconfiguring an I/O subsystem of a computer electronic complex (CEC), as defined in claim 1, further comprising the step of:

providing an I/O channel identifier of a physical channel to represent the I/O resource.

5. A method of reconfiguring an I/O subsystem of a computer electronic complex (CEC), as defined in claim 1, further comprising the step of:

providing an I/O device identifier of a physical device to represent the I/O resource.

6. A method of reconfiguring an I/O subsystem of a computer electronic complex (CEC), as defined in claim 2, further comprising the step of:

providing an I/O channel identifier of a physical channel to represent the I/O resource.

7. A method of reconfiguring an I/O subsystem of a computer electronic complex (CEC), as defined in claim 2, further comprising the step of:

providing an I/O device identifier of a physical device to represent the I/O resource.

8. A method of reconfiguring an I/O subsystem of a computer electronic complex (CEC) for sharably controlling an I/O resource, as defined in claim 1, further comprising the steps of:

partitioning CEC resources into a plurality of partitions in which any partition can contain an operating system, in which the different partitions are assigned different IID values associated with the OSs in the partitions; and

including all of the IIDs for the partitions containing operating systems in the set of IIDs.

9. A method of reconfiguring an I/O subsystem of a computer electronic complex (CEC) for sharably controlling an I/O resource as defined in claim 1, further comprising the steps of:

structuring the mask to contain a field for each IID currently represented in the CEC, and locating each field in the mask with one of the IID values associated with the field; and

setting at least one of the mask fields to a state that controls one or more settings in a control block assigned the IID associated with the field.

10. A method of reconfiguring an I/O subsystem of a computer electronic complex (CEC) for sharably controlling an I/O resource as defined in claim 1, the structuring step further comprising the step of:

structuring a single bit in the mask to represent each field associated with a respective IID.

11. A method of reconfiguring an I/O subsystem of a computer electronic complex (CEC) for sharably controlling an I/O resource as defined in claim 1, including the step of:

executing a configuration-change command to add sharing controls to an I/O configuration of the CEC for a shareable I/O resource as specified in a mask of a command request block (CRQB) of the command.

12. A method of reconfiguring an I/O subsystem of a computer electronic complex (CEC) for adding shareable an I/O resource as defined in claim 11, the executing step further comprising the step of:

making a sharing set of control blocks usable as the sharing controls for a shareable I/O resource specified in the CRQB.

13. A method of reconfiguring an I/O subsystem of a computer electronic complex (CEC) for adding shareable an I/O resource as defined in claim 12, the making step further comprising the steps of:

activating a spare field in each control block in a spare sharing set of control blocks (previously copied into the I/O subsystem in a disabled state); and

setting a candidate state in each control block of the sharing set as indicated by the command in order to configure the spare sharing set of control blocks into the I/O subsystem of the CEC.

14. A method of reconfiguring an I/O subsystem of a computer electronic complex (CEC) for sharably controlling an I/O resource as defined in claim 1, including the steps of:

executing a configuration-change command to add-modify existing sharing controls for a shareable I/O resource as specified in a mask of a command request block (CRQB) of the command; and

setting a candidate state in each control block of the sharing set as indicated by the command in order to provide a candidate state for any control block not previously set to a candidate state in a sharing set of an I/O configuration for a CEC.

15. A method of reconfiguring an I/O subsystem of a computer electronic complex (CEC) for sharably controlling an I/O resource as defined in claim 14, the executing step further comprising the step of:

executing by a program associated with a particular IID of a vary-on command specifying a shared resource having a candidate state to activate the shared control for the program to allow the program to use the resource without any intervening power-on reset of the CEC or the I/O subsystem.

16. A method of reconfiguring an I/O subsystem of a computer electronic complex (CEC) for add-modifying shareable an I/O resource as defined in claim 14, further comprising the steps of:

structuring a candidate access mask (CAM) provided with the add-modifying command to have a corresponding field for each IID currently represented in the CEC, each mask field being set to indicate a candidate or non-candidate state predetermined for corresponding control blocks in the sharing set; and

setting a candidate field in each control block of the sharing set to the state of a mask field located by the IID of the program associated with the respective control block in the sharing set.

17. A method of reconfiguring an I/O subsystem of a computer electronic complex (CEC) for sharably controlling an I/O resource as defined in claim 1, including the steps of:

executing a configuration-change command to delete-modify existing sharing controls for a shareable I/O resource as specified in a mask of a command request block (CRQB) of the command; and

setting a candidate state in each control block of the sharing set as indicated by the command in order to remove from candidate state any control block previously set to a candidate state or to an active state in a sharing set of an I/O configuration for a CEC.

18. A method of reconfiguring an I/O subsystem of a computer electronic complex (CEC) for delete-modifying a shareable I/O resource as defined in claim 17, the executing step further comprising the steps of:

structuring a non-candidate access mask (CAM) provided with the delete-modifying command to have a corresponding field for each IID currently represented in the CEC, each mask field being set to indicate a candidate or non-candidate state predetermined for corresponding control blocks in the sharing set; and

setting a candidate field in each control block of the sharing set to the state of a mask field located by the IID of the program associated with the respective control block in the sharing set to enable a control block previously in active or candidate state to be removed from the I/O configuration.

19. A method of reconfiguring an I/O subsystem of a computer electronic complex (CEC) for sharably controlling an I/O resource as defined in claim 1, further comprising the steps of:

specifying the I/O resource as a shared channel in a command having a special operation code and a channel identifier and a mask field for each control block in a sharing set for indicating the configuration states of the control blocks.

20. A method of reconfiguring an I/O subsystem of a computer electronic complex (CEC) for sharably controlling an I/O resource as defined in claim 1, further comprising the steps of:

specifying the I/O resource as a shared device in a command having a special operation code and a subchannel identifier and a mask field for each control block in a sharing set for indicating the configuration states of the control blocks.