FAULT-TOLERANT PROGRAMS AND THEIR RELIABILITY

The paper reviews and extends available techniques for achieving fault-tolerant programs. The representation of the techniques is uniform and is illustrated by simple examples. For each technique a fault tree has been developed to derive failure probability from the probabilities of the basic fault events. This enables the subsequent analysis of program-failure causes and the reliability modeling of computer programs. Numerical examples support the comparison of the reviewed techniques. The models can be used to evaluate numerical values of program reliability in a relatively simple way. The models deal with program reliability for a single run which seems more practical and straightforward than dealing with distributions as for hardware systems. Evaluations obtained by using our models correspond to those used in the literature. Yet our procedures are computationally simpler. © 1990 IEEE