Cost-Benefit Analysis of a Computer System with Priority to S/W Replacement over H/W Repair Activities Subject to Maximum Operation and Repair Times

The emphasis of the present study is on the evaluation of reliability measures of a computer system with independent hardware (h/w) and software (s/w) failures. A single repair facility is provided immediately for conducting repair activities of h/w and s/w. Preventive maintenance of the system is done after a maximum operation time. Replacement of the h/w by new one is made in case server fails to complete its repair in a given maximum time. However, only replacement of the s/w is done by new one giving some replacement time. Priority is given to s/w replacement over h/w repair activities. The failure time distribution of the h/w and s/w follows negative exponential while the distributions of preventive maintenance, repair and replacement time are taken as arbitrary with different probability density functions. Illustration for a particular case is given to show the graphical behaviour of some important reliability measures.