24/06/2005 - Controller General of Patents, Designs, and Trade Marks

(21) Application No. 1223/DEL/2001 A (22) Date of filing of Application: 05/12/2001
(54) Title of the invention: METHOD AND SYSTEM FOR CONTROLLING ACCESS TO DATA IN
SHARED DISK PARALLEL DATA FILE
(51) International Classification 7 :
G06F 17/30
(30) Priority Data :
(31) Document No.:09/737,393
(32) Date : 15/12/2000
(33) Name of convention country : U.S.A.
(66) Filed U/s 5(2) : NIL
(61) Patent of addition to application No. :
NA
(62) Filed on : NA
(63) Divisional to Application No. :NIL
(64) Filed on : NA
Total Pages: 18
(57) Abstract:
(71) Name of the applicant:
International Business Machine Corporation,
Address of the Applicant:
Armonk, New York 10504 U.S.A.
(72) Name of the Inventor:
WANG–KNOP Kuei–Yu;
CURRAN Robert Johan;
KANDANAI Radha Rani;
The system for controlling access to data in a shared disk parallel data file comprising
means (6.1, 6.8, 6.3) to determine communication failure to one node in a two node system, means
(6.1, 6.8) to determine whether said failed node has been enabled for a single node quorum
operation, and means (6.1, 6.8, 6.5) to fence data access from said failed node, upon detection of a
single node enabled status.
The system is provided for continuing node operations in quorum–based protocls. This is
particulary valuable in the situation in which a group of nodes comprises only two nodes and in
which communications to a node is lost. Provision is made for adding additional status indications
to each node indicating whether or not it is enabled for single–node quorum operation. Provision is
also made for identifying one node as a primary node and another node as a secondary node for
time–out response purposes.
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