Experimental Validation of High-Speed Fault-Tolerant Systems Using Physical Fault Injection 1 R. J. Martínez 1 , P. J. Gil 2 , G. Martín 1 , C. Pérez 3 , J.J. Serrano 2 1 Instituto de Robótica 2 Dpto D.I.S.C.A. 3 Dpto. de Informática Universitat de València U. Politécnica de Valencia y Electrónica Rafael.Martinez@uv.es pgil@disca.upv.es Universitat de València Gregorio.Martin@uv.es juanjo@disca.upv.es Carlos.Perez@uv.es Abstract This paper introduces a new methodology for validation of dependable systems based on physical fault injection. The approach defines the elements of the injection environment and the requirements that are necessary to control the injection process with fine granularity, allowing for the elimination of glitches and not valid experiments and therefore making the validation process more accurate. We also show the main features of a high-speed pin level fault injection tool, AFIT (Advanced Fault Injection Tool), that incorporates most of the requirements necessary for the application of this methodology. As a practical case study we have validated FASST, a fault tolerant multiprocessor system composed of several fail-silent processor modules. The dependability of the system has been shown, including the influence of the error detection levels in the coverage and latency of the error. Keywords: Physical fault injection, dependability validation, coverage, fail-silent module. 1. Introduction When validating Fault Tolerant Systems (FTS’s), the main objective must be to demonstrate that the behavior of the system conforms to its specifications. This process is an essential prerequisite to know how well the system will tolerate faults; it also quantifies some of the parameters that allow comparisons with other systems [1][4]. 1 This work has been partially supported by the ESPRIT Project contract P5212 and by the CICYT contract TAP96-1090-C04-01.