Encoding and rebuilding data for a DASD array.

摘要

An (M-1)xM data array can be rebuilt from an array of M DASDs when up to R DASDs fail, where M is a prime number, the data array being encoded to include zero XOR sums along traverses of slopes 0, 1, 2, ..., R-1, extended cyclically over the data array. The rebuilding includes calculating XOR-sums along the traversed paths of R 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.