Overview

Application software can and should be designed to run well on power-managed computers. An ACPI platform hardware, BIOS, and operating system has a lot of information applications can use to ensure robust operation and power management decisions suitable for the user s needs. Designing and building robust power-managed applications requires that software developers focus on handling power management state transitions and coping with device changes over sleep/resume cycles. Power management application software design considerations matter for applications running on both desktops and mobile devices.

In this chapter you ll learn the benefits of power-managed application design, implementation guidelines, and an applications testing methodology, including how to handle power-down and power-up scenarios, and wake notifications issued by the operating system. Most of the examples are specific to the Microsoft Windows operating systems, Windows Millennium Edition (ME) and Windows 2000 in particular, but the concepts are applicable to other power-managed operating systems or kernels too.

In this chapter, the term sleep means the system is either in standby state or is in hibernation, because to an application program, standby and hibernation states look the same. That s because the differences are in how the operating system determines what gets powered down the application does not need to provide any additional feedback for the operating system to make the decision.

By following the guidelines in this chapter, developers can build applications that respond to sleep intelligently. Games, for example, can respond to sleep by pausing, then allowing the user to resume play from the paused state when...