A computer network comprises a number of storage controllers, each coupled to one of a plurality of storage arrays, each storage array including at least one mass storage device. Each storage controller may be coupled to at least one host processing system and to at least one other storage controller...http://www.google.com/patents/US6073209?utm_source=gb-gplus-sharePatent US6073209 - Data storage controller providing multiple hosts with access to multiple storage subsystems
