Patent ID: 8196018

Claim:
A method for performing parity checking in a disk array environment in which each parity stripe across a plurality of disk drives has an associated first and second parity value, the method comprising the steps of: verifying the associated first parity value for each of a plurality of data values; if the respective first parity value is in error, then analyzing first and second error values respectively associated with first and second parity equations; and based on the analysis, determining if one of the plurality of disk drives is faulty, wherein determining if one of the plurality of disk drives is faulty includes: determining as a first condition if the first error value and the second error value are either both non-zero or both zero; determining as a second condition if the first and second error values indicate a valid disk index for one of the plurality of disk drives; and determining as a third condition if the valid disk index is the same for error values associated with a plurality of parity stripes.