A disk controller includes memory that is accessible by both a
microprocessor and hardware parity logic. Parity-related operations are
identified by scenario, and parity coefficient subsets are stored in a
memory table for each different parity-related calculation scenario. To
perform a particular parity-related operation, the microprocessor
determines the operation's scenario and identifies the corresponding
coefficient subset. The hardware parity logic is then instructed to
perform the appropriate parity computation, using the identified
coefficient subset.