A measure of guaranteed availability and its numerical evaluation

A success (risk) measure of guaranteed availability is proposed. Using a genetic system model, the authors describe the measure and study the effects of the guaranteed level and the observation period on it. Furthermore, they introduce a numerical approach for continuous-time Markov chain models which allows component-level modeling, Coxian failure and repair distributions, time-dependent failure and repair rates and deferred repair and nondeferred repair strategies to be handled. An example of a fault-tolerant database computer system is considered and the measure of guaranteed availability is evaluated for various guaranteed levels and observation periods