ORDER-STATISTICS BASED MODELING OF GRACEFULLY DEGRADING COMPUTING SYSTEMS

Much of the existing work on gracefully degrading computing systems are only applicable when the life distribution for the system components is exponential. In this paper, we develop an order-statistics based model for these systems. We show the generality of this model by deriving expressions for system reliability, mean-time-to-failure, and mean-computations-before-failure. In addition, we derive some interesting properties for the failure rate of such a system . In particular we show that the failure rate of a gracefully degrading system with i.i.d. DFR components is also DFR if the coverage probability is less than 1/2. This generalizes a well known result for series systems.