Method and means for encoding and rebuilding data contents of up to two unavailable DASDs in an array of DASDs
February 11, 2011. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3685016 System for recovering data stored in failed memory unit Plural channel error correcting methods and means using adaptive reallocation of redundant channels among groups of channels Methods and means for simultaneously correcting several channels in error in a parallel multi channel data system using continuously modifiable syndromes and selective generation of internal channel pointers Schilling-Manela forward error correction and detection code method and apparatus Disk drive memory File system for a plurality of storage classes Skewed XOR data storage process File-based redundant parity protection in a parallel computing system Patent #: 5130992 InventorsApplicationNo. 653596 filed on 02/11/1991US Classes:714/6, Redundant stored data accessed (e.g., duplicated data, error correction coded data, or other parity-type data)714/755Double encoding codes (e.g., product, concatenated)ExaminersPrimary: Baker, Stephen M.Attorney, Agent or FirmInternational ClassesG06F 011/10G11B 020/18 AbstractA method and means for encoding data written onto an array of M synchronous DASDs and for rebuilding onto spare DASD array capacity when up to two array DASD fail. Data is mapped into the DASD array using an (M-1)*M data array as the storage model where M is a prime number. Pairs of simple parities are recursively encoded over data in respective diagonal major and intersecting row major order array directions. The encoding traverse covering a topologically cylindrical path. Rebuilding data upon unavailability of no more than two DASDs merely requires accessing the data array and repeating the encoding step where the diagonals are oppositely sloped and writing the rebuilt array back to onto M DASDs inclusive of the spare capacity.Other References
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