Abstract: A method of transferring a transaction workload of a primary process pair. The primary pair has access to a stable storage volume for storing data items and a log for storing transaction processing updates to data items. A backup process pair is established for the primary pair and information is transferred thereto so that it can take over for the primary pair should that pair fail. Additionally, a lock table is maintained and update records are written to the log by the primary pair. The update records include any locks from the lock table that related to the update records. When a failure of the primary pair occurs, the storage volume is locked, and the backup pair reads the log to reconstruct a lock table. Once the locks have been reconstructed, the lock on the storage volume is released and the backup pair operates to process the workload.

Abstract: A modified transaction registration protocol is disclosed. The registration protocol is inherently centralized in that processes requesting registration to participate in the work of a transaction, must send a request to a Broadcast Owner CPU which is the CPU that initiated the transaction. The processes wait, suspended, until a response is received from the Broadcast Owner CPU. However, if the Broadcast Owner CPU fails to respond to the registration request, then the processes that are waiting are incapable performing work for the transaction. While a CPU failure may not occur often, in a fault-tolerant system, such events must be accounted for. Therefore, the transaction registration protocol is modified to revert to a Full Broadcast transaction protocol and complete any outstanding registration requests. This is accomplished by distributing transactions to all of the CPUs in the system, and in each CPU forcing the completion of registration requests in each CPU.

Abstract: A method of transferring a transaction workload of a primary process pair. The primary pair has access to a stable storage volume for storing data items and a log for storing transaction processing updates to data items. A backup process pair is established for the primary pair and information is transferred thereto so that it can take over for the primary pair should that pair fail. Additionally, a lock table is maintained and update records are written to the log by the primary pair. The update records include any locks from the lock table that related to the update records. When a failure of the primary pair occurs, the storage volume is locked, and the backup pair reads the log to reconstruct a lock table. Once the locks have been reconstructed, the lock on the storage volume is released and the backup pair operates to process the workload.

Abstract: A modified transaction registration protocol is disclosed. The registration protocol is inherently centralized in that processes requesting registration to participate in the work of a transaction, must send a request to a Broadcast Owner CPU which is the CPU that initiated the transaction. The processes wait, suspended, until a response is received from the Broadcast Owner CPU. However, if the Broadcast Owner CPU fails to respond to the registration request, then the processes that are waiting are incapable performing work for the transaction. While a CPU failure may not occur often, in a fault-tolerant system, such events must be accounted for. Therefore, the transaction registration protocol is modified to revert to a Full Broadcast transaction protocol and complete any outstanding registration requests. This is accomplished by distributing transactions to all of the CPUs in the system, and in each CPU forcing the completion of registration requests in each CPU.