A Self-Checking Computer Module Based on the Viper Microprocessor — A Building Block for Reliable Systems

Abstract

A self-checking computer module suitable for use in a variety of safety-critical applications is described. The module is able to detect any errors generated in normal processing, and also test itself comprehensively for latent faults. The basis of the module is an enhanced version of the VIPER microprocessor, a formally proven device designed specifically for use in safety-critical applications. To minimise component count, methods of incorporating the error detection and handling mechanisms into the VIPER chips themselves are given. Also described are techniques for implementing the module as a multi-card system. By defining a standard backplane and designing a general purpose set of cards, self-checking computers of various sizes can be configured without additional hardware design. The paper concludes by showing how two or more self-checking modules can be connected in various fault-tolerant configurations.