Operating System Issues

This chapter describes the different aspects of operating system issues. It focuses on a number of operating system issues that are unique to massively parallel processors (MPPs) and that can impact both the performance and usability of an MPP in an open systems environment. Sections address multiple users, virtual memory, scheduling, virtual processors, and /or distributed memory-multiple instruction, multiple data (DM-MIMD). Shared memory symmetric multiprocessors (SMPs) have been in the mainstream of processing for some time, and their operating systems are natural outgrowths of the time-sharing operating systems of the early 1970s. Instead of a single processor to service the job queue, there are several. Parallelism occurs by running multiple independent jobs, concurrently, on several processors. In some environments, the MPP will be viewed as a single-purpose production engine, dedicated to one compute-intensive job. The processor services one job at a time on its queue and has no interactive component.