Abstract: An I/O module is provided to service I/O requests from a host to access storage media. Data blocks of the storage media are encrypted with an old key, and the I/O module performs key rotation to cause data blocks to be re-encrypted with a new key.

Abstract: An I/O module is provided to service I/O requests from a host to access storage media. Data blocks of the storage media are encrypted with an old key, and the I/O module performs key rotation to cause data blocks to be re-encrypted with a new key.

Abstract: A fault tolerant cluster of computer systems includes a “process quad” comprising four duplicate processes—a primary process and a backup process on a primary system, and a primary process and a backup process on a backup system. The state of the backup process on the primary system is maintained by receiving checkpoint information from the primary process on the primary system, and the states of the primary and backup processes on the backup system are maintained by receiving checkpoint information either directly or indirectly from the primary process on the primary system.

Abstract: In a multiple processing system or cluster, a pair of processes, assuming the role of a primary process and a backup process to the primary process, are replaced on-line by stopping the backup process; creating the replacement backup process; checking to ensure compatibility between the primary and replacement backup processes so that communication between them is possible and information sent by the primary process to the replacement will be correctly received and handled; providing the replacement backup process with that state of the primary process needed in order to take over the function and operation of the primary process; switching roles so that the replacement backup process now takes over the function and operation of the primary, and the primary becomes the backup; and repeating the steps of creating, checking, providing and switching, to conclude with a newly-installed replacement primary process and a replacement backup process, completing the on-line replacement of the process pair.

Abstract: A plurality of multiprocessor systems is arranged in a high speed network to allow any processor in one system to communicate with any processor in another system. The network is configured as a multi-node dual bidirectional ring having a multiprocessor system at each node. Packets of information may be passed around the ring in either of two directions and are temporarily stored in buffer memory locations dedicated to a selected destination processor in a selected direction between each successive transfer between neighboring nodes. The buffer locations are managed so that they can request an adjacent node to stop transmitting packets if the buffer is becoming full from that direction and request resumption of transmission of packets as the buffer empties.

Abstract: A plurality of multiprocessor systems is arranged in a high speed network to allow any processor in one system to communicate with any processor in another system. The network may be configured as a multi-node dual bidirectional ring having a multiprocessor system at each node. Packets of information may be passed around the ring in either of two directions and are temporarily stored in buffer memory locations dedicated to a selected destination processor in a selected direction between each successive transfer between neighboring nodes. The buffer locations are managed so that a node can request an adjacent node to stop transmitting packets if the buffer is becoming full from that direction and request resumption of transmission of packets as the buffer empties.