Software Fault-Tolerance based on Observation and Control of Distributed Programs

University Of Texas At Austin, Austin TX

Investigators

Abstract

To reduce the risks associated with software faults, the research focuses on a fault tolerance method based on controlled execution with lookahead. In this approach, a program is run in a lookahead mode without affecting the external environment. During lookahead, sufficient information is traced so that it can be analyzed for faults. If the analysis of the execution shows that there are no faults, then the lookahead execution is committed and its effects are visible to the environment. Otherwise, the results from the lookahead execution are discarded, and the system is run in a controlled mode. In this mode, the system exercises control by introducing additional synchronization or by changing the order of messages to avoid the fault that occurred during lookahead. There are three main components of the project - algorithms for detection of software faults, algorithms for automatic control such as insertion of control messages and reordering of messages based on lookahead, and a system which supports controlled execution with lookahead. For detection of software faults, previous algorithms will be extended to work for more general model of computation in the presence of failures. For automatic control, the project will focus on synchronization faults in concurrent programs. Finally, a system in Java that supports controlled execution with lookahead will be developed.