FAULT INJECTION FOR DEPENDABILITY VALIDATION - A METHODOLOGY AND SOME APPLICATIONS

This paper addresses the problem of the dependability validation of fanlt-tolerant computing systems and more specifically the validation of the fault-tolerance mechanisms. The presented approach is based on the use of fault-injection at the physical level on a hardware/software prototype of the considered system. The place of this approach in a validation directed design process, as well as its place with respect to related works on fault-injection, is clearly identified. The major requirements and problems related to the development and application of a validation methodology based on fault injection are presented and discussed. Emphasis is put on the definition, analysis, and use of the experimental dependability measures that can be obtained. The proposed methodology has been implemented through the realization of a general pin-level fault injection tool (MESSALINE) and its usefulness is demonstrated by the application of MESSALINE to the experimental validation of two systems: 1) a subsystem of a centralized computerized inerlocking system for railway control applications and 2) a distributed system corresponding to the current implementation of the dependable communication system of the ESPRIT Delta-4 Project. © 1990 IEEE