IMPROVED STORAGE UNIT GENERATION OF REDUNDANCY INFORMATION IN A REDUNDANT STORAGE ARRAY SYSTEM

摘要

A redundant array based data storage system used in computer systems for reducing the amount of time required to modify data records stored in the redundant array. The storage system reduces the number of transmissions between a storage unit within the redundant array and the array controller by incorporating a parity storage unit which is programmed to perform operations necessary to the calculation of a "parity code" which is used for error detection and correction. By integrating the redundancy information generation into the storage unit used to store the parity information, the number of transmissions between various component parts of the system is reduced, and so the amount of time required to perform a "read-modify-write" operation is reduced. Disk-type parity units having more than one read/write head are used to further increase the performance of the storage system by reducing the disk rotational latency time.