! " #$ %&$’ ()*+ ,)( - . /*0 , * ),0+ 1 Department of Mathematics, Graphic Era University, Dehradun 248002, India 2 Department of Mathematics, Statistics and Computer Science, G.B. Pant University of Agriculture and Technology, Pantnagar263145, India *Corresponding Author: mangeyram@gmail.com In this paper we propose a new coverage model which shows improvement in the availability of the system and the reduction in the cost which are important measures for reliability. The present study discusses the effect of coverage factor on the reliability characteristics of a parallel redundant complex system. The system is analysed under Preemptive resumerepair policy. Using the concept of coverage factor, the availability and cost analysis of the system have been computed and analysed by graphical illustrations. Keywords: Coverage factor, Optimal maintenance policy, Performability, Availability, Cost analysis. A system is composed of subsystems. It is assumed that every subsystem must survive in order to survive the system. This assumption leads to the fact that the system reliability is the product of the divided reliability of each sub system. It is well known that each component and the system will be in one of the two states, either successful or failed. The components are independent and identically distributed (i.i.d.) and the reliability of each component are active or passive. The reliability characteristics are obtained by assuming that the fault detection and switch over mechanism are perfect. As the coverage directly influences the system reliability, it is important to characterize the recovered fault proportion in order to accurately determine the coverage factor of redundant equipment and to calculate the impact of the parameter on the overall system reliability.