TY - JOUR T1 - An adaptive algorithm for tolerating value faults and crash failures JF - Parallel and Distributed Systems, IEEE Transactions on Y1 - 2001 A1 - Ren,Yansong A1 - Michel Cukier A1 - Sanders,W. H. KW - active replication communication KW - adaptive algorithm KW - adaptive fault tolerance KW - adaptive majority voting algorithm KW - AQuA architecture KW - client-server systems KW - CORBA KW - crash failures KW - data consistency KW - data integrity KW - Dependability KW - distributed object management KW - fault tolerant computing KW - objects replication KW - value faults AB - The AQuA architecture provides adaptive fault tolerance to CORBA applications by replicating objects and providing a high-level method that an application can use to specify its desired level of dependability. This paper presents the algorithms that AQUA uses, when an application's dependability requirements can change at runtime, to tolerate both value faults in applications and crash failures simultaneously. In particular, we provide an active replication communication scheme that maintains data consistency among replicas, detects crash failures, collates the messages generated by replicated objects, and delivers the result of each vote. We also present an adaptive majority voting algorithm that enables the correct ongoing vote while both the number of replicas and the majority size dynamically change. Together, these two algorithms form the basis of the mechanism for tolerating and recovering from value faults and crash failures in AQuA VL - 12 SN - 1045-9219 CP - 2 M3 - 10.1109/71.910872 ER -