Abstract: A disk drive array with a controller which provides: dynamic remapping for grown defects in the disk drives, multi-thread request processing with a variable number of forkings, defect tracking with both logical and physical lists, guarded writes of less than a full stripe optimized by selectably using the redundancy to limit the number of sectors involved, association of multiple operations with a single disk request in order to facilitate error handling, use of an access hiatus as indication of further opportunity to rebuild data in background, and scatter/scatter (bidirectional scatter/gather) operations.