Patent 5155678 Issued on October 13, 1992. Estimated Expiration Date: October 13, 2009. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
A method for maintaining switchover between a backup and degrading active processor, which switchover is transparent to a terminal accessing the active processor with atomic transactions. The backup processor prepares for an outage by the active processor by synchronizing, tracking, and monitoring the active processor's log entries. When the active processor fails, the backup processor performs the necessary recovery processing and takes over user-transactions processing as the new active processor.
Other References
T. L. Borden et al., "Method Using Token and Token Table to Prevent I/O Operations to Selected Data Sets After Subsystem Failure", IBM Technical Disclosure Bulletin, vol. 28, No. 3, Aug. 1985, page 1108
H. A. Beier et al., "Shared Data Availability Across a System Failure", IBM Technical Disclosure Bulletin, vol. 28, No. 3, Aug. 1985, pp. 950-951
Mutzeneek, "using mini-Computers in Systems Engineering", Electronic Engineering, vol. 43, No. 516, pp. 45-47, Feb. 1971
Serlin, "Fault-Tolerant Systems in Commerical Applications", IEEE Computer, vol. 17, No. 8, pp. 19-30, Aug. 1984
October 13, 2009. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
