(54) APPARATUS AND METHOD FOR RECONSTRUCTING DATA USING CROSSPARITY STRIPES ON STORAGE MEDIA
(75) Inventor: James Prescott Hughes, Lino Lakes,
(73) Assignee: Storage Technology Corporation,
Louisville, CO (US) ( * ) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 0 days.
(21) Appl. No.: 09/490,258
(22) Filed: Jan. 24, 2000 (51) Int. Cl.7 ......................... .. G06F 11/00; G06F 12/00 (52) U.S. Cl. ............. .. 714/804; 711/114 (58) Field of Search ............................... .. 714/701, 702, 714/804, 723, 766, 711, 770; 711/114 (56) References Cited U.S. PATENT DOCUMENTS 4,201,976 A 5/1980 Patel ......................... .. 371/50 5,351,246 A * 9/1994 Blaum et al. ................ .. 714/6 5,537,567 A 7/1996 Galbraith et al. 5,579,475 A 11/1996 Blaum et al. 5,523,595 A 4/1997 Bailey 5,805,788 A * 9/1998 Johnson .................... .. 711/114 5,812,753 A * 9/1998 Chiariotti ...... .. 714/54 5,862,158 A * 1/1999 Baylor et al. . . . . . . .. 714/6 5,884,098 A * 3/1999 Mason, Jr. ..... .. 710/1 6,092,215 A * 7/2000 Hodges et al. . 711/114 6,138,201 A * 10/2000 Rebalski ..... .. 711/111 6,223,300 B1 * 4/2001 Gotoh ...................... .. 711/114
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Tape group parity protection Johnson, T.; Prabhakar, S. Mass Storage Systems, 1999. 16th IEEE Symposium on , 1999 pp.: 72-79.*
On variable scope of parity protection in disk arrays by Franaszek, P.A.; Robinson, J .T. Computers, IEEE Transactions on , vol.: 46 Issue: 2 , Feb. 1997 pp.: 234-240.* Redundant optical storage using DVD-RAM library— Tanabe et al. NTT Integrated Inf. & Energy Syst. Labs., Tokyo, Japan: Mass Storage Systems, 1999. 16th IEEE Symposium on, On pp.: 80-87 Mar. 15-18, 1999 San Diego, CA, USA.*
Patel; Adaptive Cross-Parity (AXP) Code For a High-Density Magnetic Tape System; IBM J . Res. Develop.; Vol 29, No 6, Nov. 1985; pp 546-526.
Primary Examiner—Phung M. Chung
Assistant Examiner—Cynthia Britt
(74) Attorney, Agent, 0r Firm—Carstens, Yee & Cahoon, L.L.P.
An apparatus and method for reconstructing missing data using cross-parity stripes on a storage medium is provided. The apparatus and method may operate on data symbols having sizes greater than a data bit. The apparatus and method makes use of a plurality of parity stripes for reconstructing missing data stripes. The parity symbol values in the parity stripes are used as a basis for determining the value of the missing data symbol in a data stripe. A correction matrix is shifted along the data stripes, correcting missing data symbols as it is shifted. The correction is performed from the outside data stripes toWards the inner data stripes to thereby use previously reconstructed data symbols to reconstruct other missing data symbols.
28 Claims, 6 Drawing Sheets
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