Chapter 4 - OpenVMS Process Structure (II)

Abstract

This chapter describes the OpenVMS process structure. A process is the basic entity that is scheduled for execution by the processor. A process represents a single thread of execution and consists of an address space and both hardware and software context. The software context of a process is defined by operating system software and is system dependent. A process may share the same address space with other processes or have an address space of its own. There is, however, no separate address space for system software and therefore, the operating system must be mapped into the address space of each process. The hardware context of a process is defined by a privileged part that is context switched with the Swap Privileged Context instruction, and a non-privileged part that is context switched by operating system software.