Software rejuvenation in maritime applications

摘要

In recent years much research has been focused on finding the causes of computer system failures. The results of this research led in observing that these failures are caused more due to software faults than due to hardware faults. Therefore, for constructing a reliable system it is necessary to improve software reliability. Although the great effort performed in this area, fault avoidance is very difficult for complex software systems. When software applications run continuously for a long period of time, error conditions are accumulated and the result is performance degradation or even a crash failure. This phenomenon has been reported as software aging. Software rejuvenation is very important way to counteract the phenomenon of software aging and system failures. It is a preventive and proactive solution and in a few words is the restart of an application at a clean internal state periodically. The modelling in this paper is formulated under a Homogeneous and a Non-Homogeneous Continuous Time Markov Chain framework. Additionally the cost of performing rejuvenation is also taken into consideration and a cost function for the model is produced and furthermore a rejuvenation policy is proposed for a maritime application. Finally, a numerical example is presented where the case of a software application on board of a ship is examined. Software rejuvenation procedure will be applied for a ship's propulsion automation in order to determine the best rejuvenation policy and to minimize the overall unavailability of the ship.