System and method for providing opportunistic file access in a network environment

• US 5,978,802 A
• Filed: 05/05/1997
• Issued: 11/02/1999
• Est. Priority Date: 06/07/1995
• Status: Expired due to Term

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Hurvig, Hans
• Primary Examiner(s): Kulik, Paul V.
• Application Number:
  US08/851,370
• Time in Patent Office: 911 Days
• Field of Search: 707/8, 707/10, 395/726, 395/200.31, 395/200.33, 711/152, 711/135, 710/200, 709/203
• US Class Current: 710/200
• CPC Class Codes: G06F 12/0813 with a network or matrix configuration
• CPC Class Codes: G06F 12/0866 for peripheral storage systems, e.g. disk cache
• CPC Class Codes: G06F 16/10 File systems; File servers
• CPC Class Codes: G06F 2212/311 In host system
• CPC Class Codes: Y10S 707/959 Network
• CPC Class Codes: Y10S 707/99938 Concurrency, e.g. lock management in shared database

Abstract

A file allocation and management system for a multi-user network environment is disclosed. At least one server and two or more clients are disposed along the network in communicating via a request/response transfer protocol. Files directed for shared usage among the clients along the network are stored at the server. Each client is adapted to communicate with the server through a plurality of identifier sockets, wherein a first identifier socket is configured for bi-directional communication and a second identifier socket is configured for unidirectional communications initiated by the server. Files normally stored at the server, under appropriate circumstances may be temporarily stored in an internal cache or other memory at each client location, when the file is in use.

Claims

1. A method for managing file access in a computer system having a server process with a file directed for shared usage, a first and a second client processes, a first bi-directional communication channel between the first client process and the server, a second bi-directional communication channel between the second client process and the server, and a signaling channel between the server and the first and second client processes, the method comprising the steps of:

transmitting by the first client through the first communication channel a request to the server for the file;

transmitting by the server the file to the first client through the first communication channel;

notifying the first client by the server that the first client has an opportunistic lock on the file; and

sending by the server a message to the first client through the signaling channel that the client must relinquish the opportunistic access to the file.

2. A computer-readable medium having computer-executable instructions for performing the steps recited in claim 1.

3. The method of claim 1, further comprising the step of determining by the server whether the file is available to the client for opportunistic access;

and

wherein the sending by the server step is performed when the server determines that opportunistic access is no longer available.

4. The method of claim 3, further comprising the steps of:

transmitting by the first client through the first communication channel a notification request to the server that the first client is relinquishing access to the file;

determining by the server whether the relinquished file is available for opportunistic access by the second client; and

notifying the second client by the server through the second communication channel that the file is available for opportunistic access.

5. The method of claim 1, wherein the signaling channel is bi-directional between the first client and server.

6. A computer-readable medium having computer-executable instructions for performing the steps recited in claim 5.

7. The method of claim 1, wherein the first and second client processes have independent signaling channels from the server.

8. The method of claim 7, wherein the signaling channels between the server and the first and second clients are bi-directional.

9. A method for allocating and managing files in a multi-user network environment of the type having at least one server with a file directed for shared usage, and a plurality of clients interconnected with the server through a network link, each client having at least two identifier sockets, wherein a first identifier socket is configured for bi-directional communication between the client and the server and a second identifier socket is configured for communications initiated by the server, the method comprising the steps of:

transmitting by the client through said first identifier socket a request to the server for the file;

transmitting by the server the file to the requesting client through the first identifier socket;

notifying the client by the server whether the client has an opportunistic lock on the file or whether the file must be maintained at the server; and

sending by the server a message to the client through the second identifier socket that the client must relinquish the opportunistic access to the file.

10. The method of claim 9, wherein the second identifier socket is configured for bi-directional communications.

11. The method of claim 9, wherein the second identifier socket is configured for unidirectional communications.

12. The method of claim 11 further comprising the steps of:

transmitting by the client through the first identifier socket a notification request to the server that the client is relinquishing access to the file;

determining by the server whether the relinquished file is available for opportunistic access by a second client accessing the file; and

notifying the second client by the server through the second identifier socket of the second client that the file is available for opportunistic access.

13. The method of claim 11 further comprising the step of relinquishing by the client the opportunistic lock on the file by transmitting to the server any portions of the file that have been modified by the client.

14. The method of claim 11 wherein the step of determining whether the file is available to the client for opportunistic access includes the step of referencing an opportunistic file table maintained by the server comprising information related to which clients have open access to the file and whether the file is open for read-only or read-write access.

15. The method of claim 12 wherein the step of determining whether the file is available to a second client for opportunistic access includes the step of referencing an opportunistic file table maintained by the server comprising information related to which clients have open access to the file and whether the file is open for read-only or read-write access.

16. A computer-readable medium having computer-executable instructions for performing the steps for a method for allocating and managing files in a multi-user network environment of the type having at least one server with a file directed for shared usage, and a plurality of clients interconnected with the server through a network link, each client having at least two identifier sockets, wherein a first identifier socket is configured for bi-directional communication between the client and the server and a second identifier socket is configured for unidirectional communications initiated by the server, the method comprising the steps of:

transmitting by the client through said first identifier socket a request to the server for the file;

determining by the server whether the file is available to the client for opportunistic access;

transmitting by the server the file to the requesting client through the first identifier socket;

notifying the client by the server whether the client has an opportunistic lock on the file or whether the file must be maintained at the server; and

sending by the server a message to the client through the second identifier socket that the client must relinquish the opportunistic access to the file when the server determines that opportunistic access is no longer available.

17. The computer-readable medium of claim 16, further comprising computer-executable instructions for performing the steps of:

transmitting by the client through the first identifier socket a notification request to the server that the client is relinquishing access to the file;

determining by the server whether the relinquished file is available for opportunistic access by a second client accessing the file; and

notifying the second client by the server through the second identifier socket of the second client that the file is available for opportunistic access.

18. The computer-readable medium of claim 16, further comprising computer-executable instructions for performing the steps of relinquishing by the client the opportunistic lock on the file by transmitting to the server any portions of the file that have been modified by the client.

19. The computer-readable medium of claim 16, wherein the step of determining whether the file is available to the client for opportunistic access includes the step of referencing an opportunistic file table maintained by the server comprising information related to which clients have open access to the file and whether the file is open for read-only or read-write access.

20. The computer-readable medium of claim 17, wherein the step of determining whether the file is available to a second client for opportunistic access includes the step of referencing an opportunistic file table maintained by the server comprising information related to which clients have open access to the file and whether the file is open for read-only or read-write access.