Patent ID: 6101588
Filing Date: 2000-08-08
Classification: G06F

Abstract:
A mass storage subsystem for use in a digital data processing system, the digital data processing system also including at least one host computer for generating access requests, the mass storage subsystem comprising:A. a data storage subsystem including at least one data storage device, the data storage device including at least one logical data store for storing at least one data item;B. a cache memory including a plurality of cache slots for caching data items from respective logical data stores provided thereto by said data storage subsystemC. a plurality of cache locks each for use in regulating access to an associated one of said cache slots;D. a device lock for regulating access to all of the cache slots caching data items from respective logical data stores of said at least one data storage device; andE. a host adapter for receiving access requests from said host computer, the host adapter being responsive to each respective access request to initially determine whether it holds the device lock associated with the data storage device containing the data item to be accessed in response to the respective access request, the host adapter, in response to a negative determination, determining whether the logical data store containing the data item to be accessed is cached in said at least one cache slot and, if so, using the slot lock associated therewith to control access thereby to the data item to be accessed regardless of the condition of the device lock.