When an amount of write data instructed by an upper-level system is small, a plurality of disk units are accessed individually and data split in sectors is written therein (Level 5 RAID). When an amount of write data instructed by the upper-level system is large, the plurality of disk units are accessed...http://www.google.de/patents/US5666511?utm_source=gb-gplus-sharePatent US5666511 - Deadlock suppressing schemes in a raid system
