Reliability, availability and profit analysis of a two-unit hot standby hardware-software system incorporating different types of coverages

The objective of the present paper is to analysis a stochastic model on a two-unit hot standby hardware-software system with consideration of different types of fault detection/recovery coverages. The fault detection coverage is conditional probability of detecting a fault given that fault has occurred whereas the fault recovery coverage is conditional probability of recovery of a fault given that fault has occurred and has been detected. Further hardware and software components failures are automatically detected/recovered respectively by hardware recovery and software recovery mechanisms. In case hardware/software auto recovery mechanism fails, then engineer is called to diagnose and repair the faults. Various indices of the system performance are obtained by using Semi-Markov Process and regenerative point techniques. Using these indices, expression for the expected profit is also obtained. The model is analyzed graphically for a particular case and various conclusions for system are drawn.