The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 27, 1994
Filed:
Jan. 03, 1994
Miguel M Blaum, San Jose, CA (US);
Ron M Roth, San Jose, CA (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method and means for coding an (M-1).times.M data array written onto an array of M synchronous recording paths and for rebuilding and writing onto spare recording path capacity when up to a preselected number R of array DASDs fail, or one DASD becomes erroneous and up to R-2 fail. Data is mapped into the parallel paths using an (M-1).times.M data and parity block array as the storage model where M is a prime number and each block extent is uniform and at least one bit in length. The (M-1).times.M data and parity block array is encoded to include zero XOR sums along a traverses of slopes 0, 1, 2, . . . , P-1, extended cyclically over said data array. Rebuilding data and parity blocks is occasioned upon unavailability of no more than R less than or equal to P recording path failures, or one recording path in error and up to R-2 recording path failures. This includes calculating XOR-sums along the traversed paths of P-1 slopes, cyclic and linear shifts and XOR operations, recovering the unavailable DASDs by means of iterative solution of a set of recursions, and finally writing the rebuilt array back to onto M recording paths inclusive of any spare paths.