File lock management in a distributed data processing system

Patent 5226159 Issued on July 6, 1993. Estimated Expiration Date:

June 4, 2012. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

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Inventors

Application

No. 893959 filed on 06/04/1992

US Classes:

707/8, Concurrency (e.g., lock management in shared database)710/200, ACCESS LOCKING711/152Memory access blocking

Examiners

Primary: Shaw, Gareth D.
Assistant: Chaki, Kakali

Attorney, Agent or Firm

Lefeve; Douglas H.

Foreign Patent References

0278312 EP. 01/13/1988

International Classes

G06F 013/00
G06F 012/16

Abstract

A distributed data processing system and method in which locks on a file are supported by a data structure that resides on either a client machine or on the file's server. When only a single client's processes are locking a file, the data structure can reside on that client. Whenever a plurality of client machines attempt to place locks on a file, the data structure is moved to the server; this forces the clients locking the file to communicate with the server when performing lock operations. When a client requests a lock from the server that cannot be granted because of an existing blocking lock, the client is informed that it should put the requesting process asleep awaiting a retry notification. When there is a change in the locks on the file that might allow such a client's now sleeping process to acquire the lock, the server sends a retry notice to the client. This awakens the sleeping process at the client, and the process then reattempts the lock operation by sending a message to the server.

Other References

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