Method and apparatus for coordination of client/server processes

• US 20030074483A1
• Filed: 05/28/2002
• Published: 04/17/2003
• Est. Priority Date: 09/25/1998
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Computer Incorporated (Apple Inc.)
• Inventors: Minow, Martin A.
• Granted Patent: US 7,233,972 B2
• Time in Patent Office: Days
• US Class Current: 719/315
• CPC Class Codes: G06F 9/466 Transaction processing
• CPC Class Codes: H04L 67/01 Protocols

Abstract

The invention provides for the coordination of client/server processes. One or more embodiments provide a completion object comprised of various states of completion of a client request. The completion object may be manipulated to transition from one state to another by both the client and server. The following states of completion may be provided: idle, ready, active, completing, completed, and acknowledged. In the idle state, the completion object is obtained by the client (by constructing a new object or retrieving an existing object that has been recycled). In the ready state, the request has been initialized but not yet issued to the server or I/O device. In the active state, the server processes the I/O request. In the completing state, the server has completed the I/O operations requested but has not yet stored the results. In the completed state, the server stores the results to be returned to the client and notifies the client. At the acknowledged state, the client examines the results, performs additional operations and frees up the completion object for use by another client request. Depending on the state of the completion object, a request to cancel the I/O operations may require varying actions. The completion object provides the ability to easily and quickly determine where in the completion process an I/O request is. Further, when a client request is canceled, the completion object provides the ability to easily identify the actions necessary to properly cancel the request.

Claims

1. A method for coordinating computer processes comprising:

obtaining an object with a first state associated with a first request;

transitioning said first state in said object to a second state.

2. The method of claim 1 further comprising notifying a computer process when said first request is complete.

3. The method of claim 1 wherein said first request may be terminated in said first state and said second state.

4. The method of claim 1 wherein said obtaining said object with said first state comprises obtaining a reference to an existing object.

5. The method of claim 1 wherein said transitioning is initiated by a client process.

6. The method of claim 1 wherein said transitioning is initiated by a server process.

7. The method of claim 1 wherein said first request is an I/O request.

8. The method of claim 1 further comprising:

determining if said first request conflicts with a second request; and

deleting said second request if a conflict exists.

9. A system comprising

a processor;

a memory coupled to said processor;

object code executed by said processor for coordinating computer processes;

said object code comprising;

a method obtaining an object with a first state associated with a first request; and

a method transitioning said first state in said object to a second state.

10. The system of claim 9, said object code further comprising a method notifying a computer process when said first request is complete.

11. The system of claim 9 wherein said first request may be terminated in said first state and said second state.

12. The system of claim 9 wherein said object code for a method obtaining said object with said first state comprises object code for a method obtaining a reference to an existing object.

13. The system of claim 9 wherein said method for transitioning is initiated by a client process.

14. The system of claim 9 wherein said method for transitioning is initiated by a server process.

15. The system of claim 9 wherein said first request is an I/O request.

16. The system of claim 9, said object code further comprising:

a method determining if said first request conflicts with a second request; and

a method deleting said second request if a conflict exists.

17. A computer program product comprising:

a computer usable medium having computer readable program code embodied therein for coordinating computer processes, said computer program product comprising;

computer readable code configured to cause said computer to obtain an object with a first state associated with a first request;

computer readable code configured to cause said computer to transition said first state in said object to a second state.

18. The computer program product of claim 17 further comprising computer readable program code configured to cause said computer to notify a computer process when said first request is complete.

19. The computer program product of claim 17 wherein said first request may be terminated in said first state and said second state.

20. The computer program product of claim 17 wherein said computer readable program code configured to cause a computer to obtain said object with said first state comprises computer readable program code configured to cause said computer to obtain a reference to an existing object.

21. The computer program product of claim 17 wherein said computer readable program code configured to cause a computer to transition is initiated by a client process.

22. The computer program product of claim 17 wherein said computer readable program code configured to cause a computer to transition is initiated by a server process.

23. The computer program product of claim 17 wherein said first request is an I/O request.

24. The computer program product of claim 17 further comprising:

computer readable program code configured to cause a computer to determine if said first request conflicts with a second request; and

computer readable program code configured to cause a computer to delete said second request if a conflict exists.

25. An apparatus for coordinating computer processes comprising:

means for obtaining an object with a first state associated with a first request; and

means for transitioning said first state in said object to a second state.

26. The apparatus of claim 25 further comprising means for notifying a computer process when said first request is complete.

27. The apparatus of claim 25 wherein said first request may be terminated in said first state and said second state.

28. The apparatus of claim 25 wherein said means for obtaining said object with said first state comprises means for obtaining a reference to an existing object.

29. The apparatus of claim 25 wherein said means for transitioning is initiated by a client process.

30. The apparatus of claim 25 wherein said means for transitioning is initiated by a server process.

31. The apparatus of claim 25 wherein said first request is an I/O request.

32. The apparatus of claim 25 further comprising:

means for determining if said first request conflicts with a second request; and

means for deleting said second request if a conflict exists.