Summary: Constraint Satisfaction as a Basis
for Designing Nonmasking Fault­Tolerance
Anish Arora 1 , Mohamed Gouda 2 , George Varghese 3
1. Department of Computer Science, The Ohio State University at Columbus
2. Department of Computer Sciences, The University of Texas at Austin
3. Laboratory for Computer Science, Massachussetts Institute of Technology
Abstract
We present a method for the design of nonmasking fault­tolerant pro­
grams. In our method, a set of constraints is associated with each program.
As long as faults do not occur, the constraints are continually satisfied un­
der the execution of program actions. Whenever some of the constraints are
violated, due to certain faults, all constraints are eventually reestablished by
subsequent execution of the program actions. To design programs thus, two
types of program actions are distinguished: ``closure'' actions and ``conver­
gence'' actions. Closure actions are the actions that perform the intended
computation of the program when all of the constraints are satisfied. Con­
vergence actions are the actions that reestablish the constraints when they
have been violated. Sufficient conditions for the validation of closure and
convergence actions are formalized in terms of a ``constraint graph''. These
conditions are illustrated by designing nonmasking fault­tolerant programs

Source: Arora, Anish - Department of Computer Science and Engineering, Ohio State University

Collections: Computer Technologies and Information Sciences