Abstract: A system is employed to maintain persistent operation information for implementation on persistent data. Bitmaps are created to track outstanding persistent operations. Should a volume of information became inaccessible, the bitmaps are evaluated to determine if outstanding persistent operations exist and, if so, these outstanding operations are performed before the volume is integrated into the logical memory space. Additionally, operation-in-progress bitmaps are utilized to indicate that persistent data within a volume is being modified.

Abstract: A hydraulic fluid storage apparatus for a transmission has a main sump and a secondary sump. The secondary sump is connected with the main sump through a restricted flow passage. The fluid within the main sump is subjected to centrifugal forces by rotating components within the transmission, such that at high speeds and high levels in the main sump, the restricted passage is closed by a centrifugal dam thereby resulting in fluid storage within the secondary sump. The fluid storage in the secondary sump returning to the main sump when the speed of the rotating components is reduced.

Abstract: A clutch assembly includes a hub with a hub friction surface and an inner surface that cooperate to define a cavity. A damper member is situated within the cavity and is in contact with the hub friction surface. The damper member is rotatable with respect to the hub so that relative movement between the damper ring and the hub friction surface results in energy absorption and dissipation to minimize unwanted clutch vibration. The damper ring is located inside the clutch hub so that it does not adversely affect transmission packaging. The clutch assembly preferably includes a member configured to direct lubricant along an inner diameter of the damper member so that it subsequently flows between the damper ring and the hub friction surface and through holes in the hub to lubricate clutch plates.

Abstract: A ring seal has an annular body and a radially inwardly extending tab member. The tab member is effectively associated or combined with a slot formed in a shaft or other rotating object to prevent rotation of the seal relative to the rotating member. The ring seal has two sides of sealing surfaces, which are annular, and one radially outer circumferential sealing surface.

Abstract: A data storage control unit is coupled to one or more host devices and to one or more physical storage units. Data is stored in one of the storage units and, for data integrity, copied to another storage unit. An updated state of the copy process (metadata) is maintained and updated in metadata tracks in a memory of the storage controller and periodically destaged to corresponding metadata tracks of a storage unit. If the copy process is interrupted, such as by a power failure, an error handling routine commences. Track state fields associated with each in-memory metadata track are initialized to an ‘invalid’ state and background staging of metadata tracks from the storage unit to the memory. After a track is staged, the associated track state field is changed to a ‘valid’ state. If a request is received to access a track of copy state data and the track has been staged (as indicated by the state of the associated track state field), the track is accessed.

Abstract: A vibration damper apparatus has two substantially freely rotatable inertia members disposed within a rotatable hub. Each of the members has a wide semi-cylindrical portion and a narrow semi-cylindrical portion with the wide portion of the first damper member being axially aligned with the narrow portion of the other damper member.

Abstract: Methods, systems, computer program products and methods for deploying computing infrastructure for clearing metadata in a storage subsystem. The method includes identifying one or more metadata tracks to clear, receiving a request from a client to clear the identified tracks, quiescing any active processes, clearing the identified tracks and resuming the quiesced processes. The request may be a single request operable to clear all metadata tracks. Alternatively, target volumes having metadata tracks to be cleared are identified and a request is received from a client for each target volume. A dynamic function list may also be created for each target volume, the list including list of functions in which the target volume is associated. After active processes are quiesced, each function in the dynamic function list of each target volume is invoked whereby the metadata tracks are cleared. The quiesced processes are then resumed.

Abstract: Methods, systems, computer program products and methods for deploying computing infrastructure for managing metadata in a storage subsystem are provided. A first metadata track is staged from disk storage to a cache storage after which a journal entry is stored in a nonvolatile storage (NVS). The journal entry includes an opcode and update data for the track. The opcode identifies the type of update to be performed and the number of tracks to be updated in the operation. Each of the other metadata tracks is staged and a corresponding journal entry stored. The journaled updates are then applied to the respective metadata track in the cache storage and the tracks destaged from cache to the disk storage.

Abstract: Methods, systems, computer program products and methods for deploying computing infrastructure for managing metadata in a storage subsystem are provided. A call is received from a client to update a portion of a metadata track. Data is also received from the client identifying at least one field of the metadata track to be updated, associated update values for the at least one field to be updated and an update type for the at least one field. A data structure field of a client interface is then populated with the identity of the at least one field and the associated update values and an opcode field of the client interface is populated with the update type. A task control block (TCB) is then allocated to the client call and, at the direction of the TCB, various operations are performed without further activity by the client. The metadata track may also be validated before being updated to ensure that the client has access only to valid updates.

Abstract: Method for selectively clearing persistent data such as metadata in a storage subsystem. The method includes identifying one or more metadata tracks to clear, receiving a request from a client to clear the identified metadata tracks, passing the request to a storage device driver, and clearing the identified metadata tracks. The metadata tracks to be cleared may be identified by a specific storage function associated with the metadata to be cleared or by a specific storage target associated with metadata. Alternatively, both a storage function and a storage target may be specified. Preferably, the request to clear one or more identified metadata tracks may be executed without affecting unrelated storage functions. In addition, the request may be executed while preserving metadata tracks unrelated to the identified metadata tracks.

Abstract: Tracks of meta data are cleared in a storage server by allocating task control blocks for executing associated tasks in parallel. Throttling and recycling of task control blocks is provided to efficiently use memory and processing resources. Under the control of a master task, task control blocks are allocated to different hierarchical levels of storage resources in the storage server, such as a logical subsystem level and a subordinate volume level. The task control blocks are not deallocated from memory until there are no further tasks to process.

Abstract: A system is employed to maintain persistent operation information for implementation on persistent data. Bitmaps are created to track outstanding persistent operations. Should a volume of information became inaccessible, the bitmaps are evaluated to determine if outstanding persistent operations exist and, if so, these outstanding operations are performed before the volume is integrated into the logical memory space. Additionally, operation-in-progress bitmaps are utilized to indicate that persistent data within a volume is being modified.

Abstract: An apparatus, system and method of concurrent high-performance transport of variable-length messages are provided. The invention overcomes the problem of transporting a message comprising more bits than the maximum allowable group transmission on a network, by fragmenting the message into a plurality of data packets and transmitting the data packets concurrently. In addition, the present invention overcomes the problem of inefficient storage space allocation for reconstruction of the message from the data packets by sending the size of the message with each data packet.

Abstract: A data storage control unit is coupled to one or more host devices and to one or more physical storage units. Data is stored in one of the storage units and, for data integrity, copied to another storage unit. An updated state of the copy process (metadata) is maintained and updated in metadata tracks in a memory of the storage controller and periodically destaged to corresponding metadata tracks of a storage unit. If the copy process is interrupted, such as by a power failure, an error handling routine commences. Track state fields associated with each in-memory metadata track are initialized to an ‘invalid’ state and background staging of metadata tracks from the storage unit to the memory. After a track is staged, the associated track state field is changed to a ‘valid’ state. If a request is received to access a track of copy state data and the track has been staged (as indicated by the state of the associated track state field), the track is accessed.

Abstract: A clutch assembly includes a hub with a hub friction surface and an inner surface that cooperate to define a cavity. A damper member is situated within the cavity and is in contact with the hub friction surface. The damper member is rotatable with respect to the hub so that relative movement between the damper ring and the hub friction surface results in energy absorption and dissipation to minimize unwanted clutch vibration. The damper ring is located inside the clutch hub so that it does not adversely affect transmission packaging. The clutch assembly preferably includes a member configured to direct lubricant along an inner diameter of the damper member so that it subsequently flows between the damper ring and the hub friction surface and through holes in the hub to lubricate clutch plates.

Abstract: A hydraulic fluid storage apparatus for a transmission has a main sump and a secondary sump. The secondary sump is connected with the main sump through a restricted flow passage. The fluid within the main sump is subjected to centrifugal forces by rotating components within the transmission, such that at high speeds and high levels in the main sump, the restricted passage is closed by a centrifugal dam thereby resulting in fluid storage within the secondary sump. The fluid storage in the secondary sump returning to the main sump when the speed of the rotating components is reduced.

Abstract: The invention alleviates wear on a plow moldboard by achieving a reduction in the effective weight of the moldboard on the roadway. One or more elastic links are interposed between the moldboard and the lifting arm which elevates and lowers the moldboard. The elastic links may be tensioned to such a degree that they serve as a counterweight for the moldboard, transmitting all or most of its weight to the lift arm and the plowing vehicle. The effective weight of the moldboard is thus reduced to such a degree that the lower edge of the moldboard bears against the roadway with little or no force, and it skids or slides along the roadway rather than grinding against it.

Abstract: A thrust bearing having an integral axially oriented resilient means provides a gap between unloaded thrust surfaces. The gap is sufficiently large to prevent bearing rollers from contacting both thrust surfaces simultaneously. Providing such a gap reduces noise from unloaded thrust bearings.