Abstract: A wellhead connector for connecting a riser or production tree to a wellhead of a subsea well utilizes a singular annular piston to lock the connector onto the wellhead. The wellhead connector includes a housing that contains dogs for engagement with the exterior of the wellhead housing. A cam ring is also included, which has an inner side for engaging the dogs and moving them inward into a locked position with the wellhead housing. The cam ring is of a reduced proportion relative to prior art. As such, the cam ring outer side is dimensioned to contact the inner side of the connector housing under load. Connecting rods connect the piston to the cam rings. As the piston moves downward, the cam ring also moves downward, forcing the dogs inward into a locked position. As the piston moves upward, the cam ring also moves upward, thereby unlocking the connector. A secondary annular piston is also provided to guarantee unlocking.

Abstract: A multi-path controller is disclosed for connecting CPU channels with DASD device subsystems. Extended channel connection time are accommodated in the polling of the devices. The request for access signals for the devices are retained for a period of time during which channel connection should be completed and then dropped. The CPU and the controller are freed to complete other work in between the polling cycles. The requests-for-access signals by the devices for connection to the channel that requested the connection does not tie up the channels and the devices while communication is being made.

Abstract: High availability is achieved in a multiprocessor system by grouping the processors into two clusters operating on different clock and power boundaries. In each cluster is an array containing a substantially identical copy of the system information relating to the operation of the processors. Each processor has a local port for accessing the local array and a remote port for accessing the remote array. When an update is made on the system information, it is made on both the local and remote arrays with the remote update performed transparently.