Data processing apparatus including a selectively resettable peripheral system.

摘要

The disclosed embodiment of a selectively resetable multiple device peripheral system, addressed logically by a host system (11), includes direct access storage devices (DASD) (18) which are connected to the host via a cache. (40). Each device can be independently addressed by any one of a plurality of addresses (16; 17), also termed logical devices and exposures (17). Since operations between DASD and cache are combined for all of the independent logical devices, resetting operations related to one independent logical device can inadvertently interfere with operations of another independent logical device. To maintain data integrity, a programmed controller accommodates logical device independence by using queues and control blocks relating to the DASD and logical devices, respectively scanning for interference of reset with non selected logical devices and forcing false completion on each such interfered with operation, including elimination from queues.