Paper Title
Mathematical Modeling Of A Computer System Under Priority In S/W Up-Gradation Over H/W Repair

A Mathematical model for a Computer system is developed by considering the aspects of priority in repair disciplines, cold standby redundancy and independent failures of components. There is a single server who visits the system immediately for conducting h/w repair and s/w up-gradation. Server inspects the h/w components at their failure to see the feasibility of repair. If repair of the h/w components is not feasible, they are replaced by its identical components. However, only up-gradation of the s/w is made by new one at their failure. And, priority for the s/w Up-gradation in one computer system is given over inspection and repair of the h/w components in another computer system. The system works as new after repair activities. All the failure time distributions are assumed to be negative exponential while that of inspection, repair and replacement times are taken as arbitrary with different probability density functions (pdf). The expression for some important performance measures of the system are derived in the steady state using semi- Markov process and regenerative point technique. The graphical behavior of MTSF, availability and profit function has been observed for particular values to various parameters and costs. The profit of the present model has also been compared with that of the model Malik and Anand [2011]. Keywords: Computer System, Hardware Failure and Priority for the Software Up-gradation, Inspection, Feasibility of Repair and Statistical Modeling.