Abstract: A redundant data storage system is provided comprising a first controller with top-level control of a first memory space and a second controller with top-level control of a second memory space different than the first memory space. The system is adapted for asynchronously reflectively writing state information by the first controller to the second memory space; alternatively the system is adapted for asynchronously reflectively writing state information by the second controller to the first memory space. A method is provided for operating the redundant data storage system by resolving any inconsistency between the existing state information and a modified state information associated with a state information change request, and for switching control in the redundant data storage system between the controllers.

Abstract: Apparatus and associated method that stores first metadata only at the same addressable storage location of a computer readable medium as that where associated first user data is stored, and afterward satisfies a read request for the first user data by retrieving the first user data from the addressable location of the computer readable medium where the first metadata is stored if the first metadata has a first value, and by reconstructing the first user data from other metadata stored at another addressable location of the computer readable medium than where the first metadata is stored if the first metadata has a second value.

Abstract: An apparatus and associated method are provided for performing a storage transaction associated with a network I/O command by employing an ASIC having an interconnect selectively coupling a plurality of dedicated purpose function controllers in the ASIC to a policy processor via a list manager in the ASIC communicating on a peripheral device bus to which the policy processor is connected.

Abstract: A redundant data storage system is provided comprising a first controller with top-level control of a first memory space and a second controller with top-level control of a second memory space different than the first memory space. The system is adapted for asynchronously reflectively writing state information by the first controller to the second memory space; alternatively the system is adapted for asynchronously reflectively writing state information by the second controller to the first memory space. A method is provided for operating the redundant data storage system by resolving any inconsistency between the existing state information and a modified state information associated with a state information change request, and for switching control in the redundant data storage system between the controllers.

Abstract: Apparatus and associated method that stores first metadata only at the same addressable storage location of a computer readable medium as that where associated first user data is stored, and afterward satisfies a read request for the first user data by retrieving the first user data from the addressable location of the computer readable medium where the first metadata is stored if the first metadata has a first value, and by reconstructing the first user data from other metadata stored at another addressable location of the computer readable medium than where the first metadata is stored if the first metadata has a second value.

Abstract: A method is provided for storing and retrieving data in a network-attached data storage device by a cooperatively multitasking real time operating system configured to execute datapath routines and a general purpose operating system kernel configured to communicate with the network.

Abstract: A data storage subsystem in a distributed storage system having a plurality of predictive failure analyzing data storage devices. The subsystem furthermore has a circuit that is responsive to a predicted failure indication by a data storage device in relation to predetermined rules stored in memory for deterministically initiating a preventive recovery either by a data recovery procedure in the data storage device or by a fault tolerance storage arrangement in the subsystem.

Abstract: An apparatus and associated method are provided for performing a storage transaction associated with a network I/O command by employing an ASIC having an interconnect selectively coupling a plurality of dedicated purpose function controllers in the ASIC to a policy processor via a list manager in the ASIC communicating on a peripheral device bus to which the policy processor is connected.