AbstractThe effects of load balancing on system and program performance of a heterogeneous distributed system model are studied using simulation techniques. A closed queuing network model is considered with two independent processors, each serving its own queue. The service speed of one processor is double the service speed of the other.A probabUistic and a deterministic load baiancing policy are studied and compared in two cases. In the first case all programs are identical and can be assigned to either of the processors. In the second case, half of the programs are dedicated to the fast processor. while the rest are generic and can be individually allocated to either of the processors. It is shown that using these policies, system and program performance depend on the degree of multiprogn. mming.