A dependability analysis for systems with global spares

Systems with global spares. in which a spare can replace any of multiple id entical primary modules, are widely used. We present efficient algorithms f or approximating the probability distribution of performance level (number of working modules) in systems with global spares and arbitrary module fail ure distribution. For nondegradable systems with global spares and arbitrar y module failure distribution, our algorithms provide the first efficient s olution for reliability. For degradable systems with global spares, our alg orithms can be used to produce upper and lower bounds on various dependabil ity measures.