Inside Macintosh: Processes

Chapter 1 - Introduction to Processes and Tasks

This chapter is a general introduction to process and task management on Macintosh computers. It describes how the Operating System controls access to the CPU and other system resources to create a cooperative multitasking environment in which your application and any other open applications execute. This environment is managed primarily by the Process Manager, which is responsible for launching processes, scheduling their use of the available system resources, and handling their termination.

This chapter also describes how you can use the services provided by the Time Manager, the Vertical Retrace Manager, and other parts of the Macintosh Operating System to schedule tasks for execution outside the time provided to your application by the Process Manager. Usually these tasks are executed in response to an interrupt.

You should read this chapter for an overview of how the Process Manager schedules applications and loads them into memory. You also need to read this chapter if you install any tasks that execute at interrupt time, which are subject to a number of important restrictions.

To use this chapter, you need to be familiar with how your application uses memory, as described in the chapter "Introduction to Memory Management" in Inside Macintosh: Memory. You should also be familiar with how your application receives events, as discussed in the chapter "Event Manager" in Inside Macintosh: Macintosh Toolbox Essentials.

This chapter begins with a general discussion of processes and tasks. Then it describes in detail the operation of the Process Manager in launching and scheduling processes. This chapter ends with a description of installing tasks that execute at interrupt time. For a more complete discussion of these topics, see the remaining chapters in this book.

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Chapter Contents

The Cooperative Multitasking Environment

About Processes

Process Creation

Process Scheduling

About Tasks

Task Creation

Task Scheduling

Task Guidelines