Exclusive use of peripheral devices

• US 6,466,982 B1
• Filed: 04/09/1999
• Issued: 10/15/2002
• Est. Priority Date: 04/09/1999
• Status: Active Grant

• Current Assignee: Oracle America, Inc. (Oracle Corporation)
• Original Assignee: Sun Microsystems Incorporated (Oracle Corporation)
• Inventors: Ruberg, Alan T.
• Primary Examiner(s): Follansbee, John A.
• Application Number:
  US09/289,796
• Time in Patent Office: 1,285 Days
• Field of Search: 709/227, 710/200
• US Class Current: 709/227
• CPC Class Codes: G06F 9/52 Program synchronisation; Mutual exclusion, e.g. by means of semaphores

Abstract

A method and apparatus for controlling the number of users that attempt to concurrently utilize a peripheral device in a network. In a network many users share various peripheral devices such as microphones, cameras, speakers, etc. In one or more embodiments of the invention, to prohibit the concurrent use of a peripheral device by multiple users, a locking mechanism is utilized. The locking mechanism allows a first user that requests access to a peripheral device to maintain an exclusive lock on that device. Once the first user has concluded using the peripheral device, the lock is released to permit another user to access the device. The locking mechanism is controlled by two protocols: the request and the grant protocols. These protocols establish the rules for exclusive access to network peripheral devices using a locking mechanism. A request includes parameters associated with the particular device, and a return address for the requesting terminal or program. The request is processed to verify the availability of the requested device and whether that device is capable to support the request based on the parameters specified. If these conditions are satisfied the request is granted. The grant protocol allows the requesting user to maintain a lock on the device for exclusive use, and monitors the locking mechanism in case of any failures. For example, if the lock on a device is not released after a user concludes the utilization of the device, the lock is released after a default period expires.

Claims

1. A method of limiting concurrent access by multiple programs to a device linked to a terminal in a computer network comprising:

accessing a first program on a server from a first terminal, wherein said server and said first terminal are connected to said computer network and wherein said first program is accessed by said first terminal through said server;

sending a request to use said device from said first terminal via said first program;

allocating a lock on said device by said first program if it is not in use by another program;

denying access by a second program to said device while said device is locked by said lock allocated by said first program; and

maintaining said lock for denying access, if said first terminal via said first program periodically submits further requests to use said device.

2. The method of claim 1, further comprising the step of directing data generated by said device to said first terminal via said first program, while said first program maintains said lock for denying accessing on said device.

3. The method of claim 1 further comprising the step of releasing said lock when no further requests have been submitted by said first program after a default time period expires.

4. The method of claim 1, further comprising the step of releasing said lock only when a terminal via said second program sends a request to use said device, if no further requests have been submitted by said first program after a default time period expires.

5. The method of claim 1, wherein said request includes device parameters for controlling said device.

6. The method of claim 5, wherein said first program is denied access to said device if said parameters are incompatible with said device.

7. The method of claim 5, wherein said parameters are modified if they are incompatible with said device.

8. The method of claim 1, wherein said first terminal requires said first program to access, lock, and use said device.

9. The method of claim 1, wherein said device is connected to a second terminal, wherein said second terminal is connected to said computer network, and wherein said first terminal via said first program access said device through said second terminal.

10. The method of claim 9, wherein said second program is located on said server and wherein said second program can only be accessed through said server.

11. The method of claim 1, wherein said server provides a computation service to said first terminal.

12. A computing system architecture comprising:

a server;

first and second terminals, having one or more devices, said first and second terminals interconnected through an interconnect fabric with one another and said server;

first and second programs located on said server, wherein said first terminal assessing said first program through said server and wherein said first terminal via said first program requesting access to said one or more devices;

said first program allocating a lock for denying access by said second program to at least one of said devices on said second terminal if it is not in use by said second program;

said first program maintaining said lock for denying access on said device, if said first terminal via said first program periodically submits further requests to use said device.

13. The computing system architecture of claim 12, wherein data generated by said device is directed to said first terminal via said first program, while said first program maintains said lock for denying access on said device.

14. The computing system architecture of claim 12 said lock is released when no further requests are submitted by said first program after a default time period expires.

15. The computing system architecture of claim 12, wherein said lock is released only when a terminal via second program sends a request to use said device, if no further requests are submitted by said first program after a default time period expires.

16. The computing system architecture of claim 12, wherein said request includes device parameters for controlling said device.

17. The computing system architecture of claim 16, wherein said first program is denied access to said device if said parameters are incompatible with said device.

18. The method of claim 16, wherein parameters are modified if they are incompatible with said device.

19. The computing system architecture of claim 16, wherein said first terminal requires said first program to access, lock, and use said device.

20. The computing system architecture of claim 12, wherein said server provides a computation service to said first terminal.

25. The computer program product of claim 12, wherein said request includes device parameters for controlling said device.

26. The computer program product of claim 25, wherein said first program is denied access to said device if said parameters are incompatible with said device.

27. The computer program product of claim 25, wherein parameters are modified if they are incompatible with said device.

21. A computer program product comprising:

a computer usable medium having computer readable program code embodied therein configured to limit concurrent access by multiple programs to a device linked to a terminal in a computer network;

said computer program product comprising;

computer readable code within a first terminal configured to cause said first terminal to access a first program on a server and to cause said first program to send a request to use said device, wherein said server and said first terminal are connected to said computer network and wherein said first program is accessed by said first terminal through said server;

computer readable code within said first program configured to cause a computer to allocate a lock on said device if it is not in use by another program;

computer readable code configured to cause a computer to deny access by a second program to said device while said device is locked by said lock allocated by said first program; and

computer readable code configured to cause a computer to maintain said lock for denying access, if said first terminal via said first program periodically sends further requests to use said device.

22. The computer program product of claim 21, further comprising computer readable code configured to cause a computer to direct data generated by said device to said first terminal via said first program, while said first program maintains said lock for denying access on said device.

23. The computer program product of claim 21 further comprising computer readable code configured to cause a computer to release said lock when no further requests are submitted by said first program after a default time period expires.

24. The computer program product of claim 21, further comprising computer readable code configured to cause a computer to release said lock only when a terminal via said second program sends a request to use said device, if no further requests are submitted by said first program after a default time period expires.

28. The computer program product of claim 21, wherein said first terminal requires said first program to access, lock, and use said device.

29. The computer program product of claim 21, wherein said device is connected to a second terminal, wherein said second terminal is connected to said computer network, and wherein said first terminal via said first program accesses said device through said second terminal.

30. The computer program product of claim 29, wherein said second program is located on said server and wherein said second program can only be accessed through said server.

31. The computer program product of claim 21, wherein said server provides a computation service to said first terminal.