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.