Patent
1994-12-06
1997-09-23
Beausoliel, Jr., Robert W.
G06F 1100
Patent
active
056713495
ABSTRACT:
The present invention provides a system of hardware and software that combine to form a redundant array of disk drives. This array provides a double means of redundancy that can reconstruct data from two simultaneously failed disks. The double redundancy means is implemented by two separate algorithms, DRR1 and DRR2. DRR1 takes the exclusive-or of all the commercial data and stores the result as redundancy data. DRR2 is similar to the algorithm described in Patel's article. As an additional feature, the implementation of DRR1 and DRR2 in the present invention is flexible enough to support either on-the-fly or read-modify-write level operation. Although both algorithms are in the prior art, the present invention improves on the run-time and space requirements of the algorithm. This improvement arises because of a novel relationship, discussed below, that exist between the individual T.sup.1 matrices and their column vectors that allows for a savings in computing the mapping of the commercial data to the redundancy data. This unique relationship is incorporated into the present systems hardware and software.
REFERENCES:
patent: 4494234 (1985-01-01), Patel
patent: 4504948 (1985-03-01), Patel
patent: 4525838 (1985-07-01), Patel
patent: 4706250 (1987-11-01), Patel
patent: 4775978 (1988-10-01), Hartness
patent: 4870643 (1989-09-01), Bultman et al.
patent: 4914656 (1990-04-01), Dunphy, Jr. et al.
patent: 4942579 (1990-07-01), Goodlander et al.
Patel, "Two-level coding for error control in magnetic disk storage products", IBM J. Res. Dev., vol. 33, No. 4, pp. 470-484 Jul. 1989.
Chen, "Symbol Error-Correcting Codes for Computer Memory Systems", IEEE Trans. on Computers, vol. 41, No. 2, pp. 252-256 Feb. 1992.
Kaneda et al., "Single Byte Error Correcting--Double Byte Error Detecting Codes for Memory Systems", IEEE, 41-46 Oct. 1980.
Bossen, "b-Adjacent Erro Correction", IBM J. Res. Dev., pp. 402-408 Jul. 1970.
"Two-Level Coding for Error Control in Magnetic Disk Storage Products," by Patel, published by IBM, San Jose. Date unknown.
"Failure Correction Techniques for Large Disk Arrays," by Gibson, et al. University of California at Berkeley, 1989, ACM.
Hashemi Ebrahim
Schulze Martin E.
Beausoliel, Jr. Robert W.
Elmore Stephen C.
Hitachi Computer Products (America ), Inc.
LandOfFree
Apparatus and method for providing data redundancy and reconstru does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus and method for providing data redundancy and reconstru, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus and method for providing data redundancy and reconstru will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1941618