A disk drive array data storage subsystem maps between virtual and physical data storage devices and schedules the writing of data to these devices. The data storage subsystem functions as a conventional large form factor disk drive memory, using a plurality of redundancy groups, each containing n+m...http://www.google.de/patents/US5371882?utm_source=gb-gplus-sharePatent US5371882 - Spare disk drive replacement scheduling system for a disk drive array data storage subsystem
