RELIABLE DISTRIBUTED SHARED MEMORY

In implementing a reliable distributed shared memory, a weak consistency model is modified to ensure that all vital data structures are properly replicated at all times. Write notices and their corresponding diffs are stored on a parameterizable number of nodes. Whenever a node (say the primary node) releases a lock, it sends its current vector timestamp, write notices generated during the time the lock was held and their corresponding diffs to a secondary node. The secondary nodes keeps this information separate from its own private data structures. If a node fails (detected by all nodes simultaneously through a group membership protocol) while holding a lock, then all nodes complete a lock release method, and enter a recovery operation. During this recovery operation, all nodes exchange all write notices and corresponding diffs, including backup write notices and diffs held by nodes on behalf of the failed node. After all information has been exchanged, diffs are applied and all nodes may start fresh.