The control of response times in multi-class systems by memory allocation

The possibility of giving different quality of service to jobs of different classes by regulating their memory allocation is examined in the context of a paged computer system.Two parameterized algorithms which partition the main memory between two classes of jobs are considered.Initially, a closed system consisting of a processor and paging and file devices, with fixed numbers of jobs, is studied to determine optimal degrees of multiprogramming and the proportion of processor time devoted to each class.Applying a decomposition approach and treating the closed system as a single server, the response times in an open system with external arrivals are studied.The object is to investigate the effect of the memory allocation parameters on the expected response times under the two algorithms.Numerical solutions and economical lower bounds for the expected response times as functions of the control parameters are obtained.A way of applying the results to systems with more than two job classes is indicated.