Profit Analysis of a Computer System With Priority to Software Replacement over Hardware Repair Subject to Maximum Operation and Repair Times

摘要

The goal of this paper is to determine some reliability and economic measures of a computer system in which h/w and s/w components fails independently direct from normal mode. The reliability model of two identical-units is developed considering computer system as a single- unit. Initially one unit is operative and the other unit is kept as cold standby. A single server is provided immediately to the system for conducting PM, repair and replacement of the components. The unit undergoes for PM after MOT directly from normal mode. The repair of the unit is done only at h/w failure subject to maximum repair time ( MRT). If repair of the unit is not possible up to a MRT, the component is replaced by new one giving some replacement time. However, only replacement of the component in the unit is made at software failure. The priority to software replacement is given over h/w repair. The failure times of the h/w and s/w components are distributed exponentially while the distribution of preventive maintenance, repair and replacement are taken as arbitrary. By adopting semi-Markov process and regenerative point technique , some important result for a particular case are also obtained to study the graphical behaviour of MTSF, availability and profit of the system model.