Suspension and reinstatement of reference handles

• US 7,237,022 B1
• Filed: 06/29/2000
• Issued: 06/26/2007
• Est. Priority Date: 06/29/2000
• Status: Expired due to Fees

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Douceur, John R., Bernet, Yoram
• Primary Examiner(s): Cardone; Jason
• Assistant Examiner(s): Kianersi; Mitra
• Application Number:
  US09/608,341
• Time in Patent Office: 2,553 Days
• Field of Search: 709/200, 709/216, 709223-224, 709226-246, 709/218
• US Class Current: 709/224
• CPC Class Codes: G06F 9/52 Program synchronisation; Mutual exclusion, e.g. by means of semaphores

Abstract

A handle administration system is described in which software agents receive handles to various resources that they can use to obtain the resources. The described embodiments provide multiple states that can be assumed by the handles. An unassigned state is provided in which handles are not assigned to a particular resource, nor can they be dereferenced to obtain pointers to any resources. An assigned state is provided in which handles are assigned to a particular resource and can be dereferenced to obtain a pointer to the resource. A suspended state is provided in which the handles are assigned to a particular resource but cannot be dereferenced to obtain a pointer to that resource. Advantageously, a suspended handle can be reinstated to assume the assigned state. In one embodiment, the handle system is implemented by incorporating a suitable field in a handle database that is used to indicate that a handle is suspended. In another embodiment, no additional fields are necessary. Rather, handle values in the handle database are manipulated to indicate that a handle has been suspended. These manipulations can be easily undone to reinstate a handle. In the described embodiment, a three state handle system can be advantageously employed to implement a two-phase commit operation.

Claims

1. A resource management system configured to manage resources comprising:

one or more resources that can be consumed by one or more agents; and

a handle administrator configured to administer a handle system in which handles to the one or more resources are provided to the agents and can be dereferenced into pointers to the one or more resources, the handle system comprising more than two states for a handle, the states comprising;

an assigned state in which a handle is associated with a resource and can be dereferenced into a pointer to that resource;

an unassigned state in which the handle is not associated with a resource and cannot be dereferenced into a pointer to any resources; and

a suspended state in which the handle is associated with a resource but cannot be dereferenced into a pointer to any resources.

2. The resource management system of claim 1 further comprising one or more agents that are consumers of one or more resources.

3. The resource management system of claim 1, wherein the handles can be suspended from the assigned state to the suspended state.

4. The resource management system of claim 1, wherein the handles can be reinstated from the suspended state to the assigned state.

5. The resource management system of claim 1, wherein the handles can be released from the suspended state to the unassigned state.

6. The resource management system of claim 1, wherein the handles can be released from the suspended and the assigned states to the unassigned state.

7. A resource management method for managing resources comprising:

providing one or more resources that can be consumed by one or more agents; and

providing a handle administrator configured to administer a handle system in which handles to the one or more resources are provided to the agents and can be dereferenced into pointers to the one or more resources, the handle system comprising more than two states for a handle, the states comprising;

an assigned state in which a handle is associated with a resource and can be dereferenced into a pointer to that resource;

an unassigned state in which the handle is not associated with a resource and cannot be dereferenced into a pointer to any resources; and

a suspended state in which the handle is associated with a resource but cannot be dereferenced into a pointer to any resources.

8. The resource management method of claim 7 further comprising providing one or more agents that are consumers of one or more resources.

9. The resource management method of claim 7, wherein the handles can be suspended from the assigned state to the suspended state.

10. The resource management method of claim 7, wherein the handles can be reinstated from the suspended state to the assigned state.

11. The resource management method of claim 7, wherein the handles can be released from the suspended state to the unassigned state.

12. The resource management method of claim 7, wherein the handles can be released from the suspended and the assigned states to the unassigned state.