US 6,959,337 B2Granted

Networked system for assuring synchronous access to critical facilities

AssigneeHewlett-Packard Development Company, L.P.

InventorsRichard J. McLaughlin, Cynthia Sakaguchi, Farangis Aberg, Marcelo M. de Azevedo

Life of this patent

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Abstract

Maintenance of a network resource is regulated by providing a lock data area that indicates an ownership status of the network resource, and a lock server process to maintain the lock data area. A client that is to perform maintenance on the network resource sends a command to the lock server process to modify the lock data area to indicate ownership of the network resource by the particular client. In response, the lock server process sends a response indicating whether or not ownership of the network resource by the client has been established. If ownership is indicated, the client performs the maintenance on the network resource. If ownership is not indicated, the maintenance is not performed. Provision is made for retries, and also for forcing the lock if a current owner becomes moribund.

Claims16

Dependent claims

A networked computing system comprising:

A) a network resource that is to be maintained;
B) a lock data area indicating an ownership status of the network resource;
C) a lock server process for maintaining the lock data area;
D) a plurality of clients that are to perform maintenance on the network resource, a client being operative to:
i) send a command to the lock server process to modify the lock data area to indicate ownership of the network resource by the client;
ii) receive a response from the lock server process indicating whether or not ownership of the network resource by the client is indicated by the lock data area;
iii) perform maintenance on the network resource only if ownership of the network resource is indicated by the lock data area;
iv) if the response indicates that ownership of the network resource by the client is not indicated by the lock data area, the client is operative to:
a) set a retry interval timer;
and
b) upon expiry of the retry interval timer, send a further command to the lock server process to modify the lock data area to indicate ownership of the network resource by the client;
and
v) after at least two unsuccessful attempts to modify the lock data area to indicate ownership of the network resource by the client, the client is operative to:
a) determine, from lock owner viability data received from the lock server process, whether or not a current lock owner is viable;
and
b) if the current lock owner is not viable, send a command that is configured to establish the client as the lock owner notwithstanding that the client is not the current lock owner.

13 more elements

A client process for maintaining a network resource, authorization to maintain the network resource being indicated by the contents of a lock data area stored on the network resource, the client process being configured to:

send a first request to modify the lock data area to indicate that the client process is authorized to maintain the network resource;
receive a first response indicating whether or not the client process has successfully modified the lock data area to indicate that the client process is authorized to maintain the network resource;
and
send maintenance commands to the network resource only if the first response indicates successful modification of the lock data area;
wherein the client process is further configured to:
set a first retry interval timer if the first response indicates that the client process has not successfully modified the lock data area to indicate that the client process is authorized to maintain the network resource;
after the first retry interval timer expires, send a second request to modify the lock data area to indicate that the client process is authorized to maintain the network resource;
receive a second response indicating whether or not the client process has successfully modified the lock data area to indicate that the client process is authorized to maintain the network resource;
and
send maintenance commands to the network resource only if the second response indicates successful modification of the lock data area;
wherein the first response includes first viability data and the second response includes second viability data, the client process being configured to:
compare the first viability data with the second viability data;
based on the comparison, either set a second retry interval timer or send a third request to modify the lock data area, the third request being configured to ensure that the lock data area will be modified to indicate that the client process is authorized to maintain the network resource;
receive a third response indicating whether or not the client process has successfully modified the lock data area to indicate that the client process is authorized to maintain the network resource;
and
send maintenance commands to the network resource only if the third response indicates successful modification of the lock data area.

13 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/071,579Filed 8 Feb 2002 · us provisional application
Priority: 23 Apr 2001
Published: US 2002/0165929 A17 Nov 2002
Granted: 25 Oct 2005
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

H04L 41/0803
Configuration management of networks or network elements: configuration setting
H04L 41/0233
Standardisation; Integration: object-oriented techniques, for representation of network management data, e.g. common object request broker…
Y10S 707/99938
Database or file accessing: concurrency, e.g. lock management in shared database
H04L
Digital communication