Robert D Curran

US Patent:

20050262143, Nov 24, 2005

Filed:

May 21, 2004

Appl. No.:

10/851812

Inventors:

Sudhir Rao - Portland OR, US
Myung Bae - Pleasant Valley NY, US
Thomas Clark - Gresham OR, US
Douglas Griffith - Apex NC, US
Roger Haskin - Morgan Hill CA, US
Shah Rezaul Islam - Tucson AZ, US
Felipe Knop - Lagrangeville NY, US
Soumitra Sarkar - Cary NC, US
Frank Schmuck - Campbell CA, US
Theodore Vojnovich - Cary NC, US
Yi Zhou - Pittsburgh PA, US
Robert Curran - West Hurley NY, US

International Classification:

G06F017/30

US Classification:

707104100

Abstract:

The acquisition of a lock among nodes of a divided cluster is disclosed. A method is performable by each of at least one node of the cluster. A node waits for a delay corresponding to its identifier. The node asserts intent to acquire the lock by writing its identifier to X and Y variables where another node has failed to acquire the lock. The node waits for another node to acquire the lock where the other node has written to X, and proceeds where Y remains equal to its own identifier. The node waits for another node to acquire the lock where the other node has written to a Z variable, and writes its own identifier to Z and proceeds where the other node has failed. The node writes a value to Y indicating that it is acquiring the lock, and maintains acquisition by periodically writing to Z.

US Patent:

20110258306, Oct 20, 2011

Filed:

Jun 25, 2011

Appl. No.:

13/168952

Inventors:

Sudhir G. Rao - Beaverton OR, US
Myung M. Bae - Pleasant Valley NY, US
Thomas K. Clark - Gresham OR, US
Douglas Griffith - Apex NC, US
Roger L. Haskin - Morgan Hill CA, US
Shah Mohammad Rezaul Islam - Cary NC, US
Felipe Knop - Lagrangeville NY, US
Soumitra Sarkar - Cary NC, US
Frank B. Schmuck - Campbell CA, US
Theodore B. Vojnovich - Cary NC, US
Yi Zhou - Pittsburgh PA, US
Robert Curran - West Hurley NY, US

International Classification:

G06F 15/173

US Classification:

709223

Abstract:

The acquisition of a lock among nodes of a divided cluster is disclosed. A method is performable by each of at least one node of the cluster. A node waits for a delay corresponding to its identifier. The node asserts intent to acquire the lock by writing its identifier to X and Y variables where another node has failed to acquire the lock. The node waits for another node to acquire the lock where the other node has written to X, and proceeds where Y remains equal to its own identifier. The node waits for another node to acquire the lock where the other node has written to a Z variable, and writes its own identifier to Z and proceeds where the other node has failed. The node writes a value to Y indicating that it is acquiring the lock, and maintains acquisition by periodically writing to Z.