"Research on architectures and interconnection networks has resulted in low-cost distributed systems with large numbers of powerful processors that can communicate at high speeds. Research on distributed operating systems has produced ways for employing this high computing potential by dividing the total workload among the available processors. By executing different programs on different processors, the system can have a high throughput. Some system programs (e.g., a file server) may also be distributed among multiple processors, to achieve higher speed and greater reliability. Many user applications can also benefit, for the same reasons. The task of distributing a single user program among multiple processors, however, clearly falls outside the scope of an operating system. Thus, to achieve this distribution, extra effort is required from the applications programmers."