Availability Analysis of Software-Hardware System with Common Cause Shock Failure, Spare and Switching Failure

Abstract

In this paper we investigate the performance indices of a computer system consisting of software and hardware along with a spare
hardware. As soon as the hardware fails, it is replaced by a spare hardware. The failures of the system can be classified in to four
categories: hardware failure, software failure, software-hardware interaction failure and common cause shock failure. The state of the
system in which some parts of hardware fail but hardware still work, is called degradation state. In such condition the software does not use those failed components of hardware then the system may still work but in very slowly. The life time and the repair time of the unit are assumed to be exponentially distributed. The switching concept also considered in the proposed paper. To solve the simultaneous differential-difference equations governing the model, SOR method is employed. Various system characteristics such as reliability, availability, mean time to failure etc. are established. The numerical result also compared by using Adaptive Neuro-Fuzzy Inference System (ANFIS). A sensitivity analysis is also performed to explore the effects of various parameters on system performance.