A performance comparison of optimally designed computer systems with and without virtual memory

In this paper, a comparison of the performance of optimally designed computer systems with and without virtual memory is made. The computer systems in question are modeled by closed queuing networks of the central server type. The design of the systems is formulated as a nonlinear optimization problem where the objective function is to maximize the throughput subject to a nonlinear cost constraint. The decision variables are the speec s of the individual devices. This optimization problem is then solved by use of the Lagrange multiplier technique. The comparisons of the systems demonstrate the affect on performance of the addition of another I/O device to handle paging and the affect on performance of the additional overhead generated by the page fault handler. Also, the optimal amount of money to be spent on main memory is investigated.