Method and means for reducing device contention by random accessing and partial track staging of records according to a first DASD format but device mapped according to a second DASD format

摘要

A staging method and means for both device read and update write operations in which messages and commands between a storage subsystem and a fixed-block formatted RAID array emulating a variable-length record (CKD) formatted device for both read and write operations are evaluated to ascertain whether the record addressing was random and truly in record mode. If they are in that mode, then partial track staging by the RAID array control from the fixed-block formatted HDDs to a subsystem cache or the like would reduce device contention by reading and staging less than full track.