File lock management in a distributed data processing system
US5226159A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 4, 1992 |
| Grant date | Jul 6, 1993 |
| Priority date | — |
| Expiry date | Jun 4, 2012 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S707/99938
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.