Chapter List

Part Overview

The following chapters introduce some important features of OpenVMS in a more detailed fashion. You do not need to read these chapters in order to use OpenVMS effectively. This material is for those readers who wish to understand a bit more about the internal workings of the OpenVMS operating system.

This chapter will expand upon that definition, explaining some of the internal structure of a process. Later sections will explain how the virtual memory and scheduling mechanisms of OpenVMS act upon a process.

Expanded Definition of Process

Earlier in this book, a process was described as a separate task that could be executed by OpenVMS. This is true, but incomplete. Because many things can qualify as "tasks to be scheduled", the following paragraphs detail what a process actually is.

OpenVMS maintains a list of processes that exist at any given time. When you, a user, log in, a process is created for you. When you log out, it is destroyed. Each batch job executes as its own process, and many DECnet network operations execute as separate processes.

A CPU executes one process at a time. If your system has one CPU, only one...