Reliability analysis of warm standby systems using sequential BDD

Warm standby sparing is a fault-tolerant design technique developed as a compromise between cold sparing and hot sparing approaches in terms of power consumption and recovery time. Warm spares have time-dependent failure behavior; before and after they are used to replace a faulty component, warm spares have different failure rates or in general failure distributions. Existing approaches for analyzing systems with warm spares typically require long computation time especially when results with high degree of accuracy are desired, and/or require exponential time-to-failure distribution for system components. In this paper, an analytical method is proposed for the reliability analysis of warm standby sparing systems. The proposed approach is based on the combinatorial model of sequential binary decision diagrams, and can generate accurate system reliability results for large systems. The approach is applicable to any type of time-to-failure distributions for the system components. Application and advantages of the proposed approach are illustrated using several examples.