With OnNow power management, the computer functions as follows:
The computer is ready for immediate use when the user presses the power button.
The computer appears to be off when not in use, but can still respond to wakeup events. In other words, the computer seems off according to what users hear and see; they have confidence that the computer is not consuming excess energy, and that data and programs are reliably saved. Wakeup events might be triggered by a device receiving some input, such as a telephone ringing, or by software that requests the computer to wake up at a predetermined time (for example, to download your e-mail so it is ready for you to read with your morning coffee).
Software adjusts its behavior when the power-state of the computer changes. The operating system and applications work together intelligently to operate the computer, to deliver effective power management according to the userÆs current needs and expectations. For example, applications do not keep the computer busy unnecessarily; instead, they proactively participate in shutting down the computer to conserve energy and reduce noise.
All devices participate in the power management scheme, whether originally installed in the computer or added later by the user. Any new device can have its power-state changed as system use dictates.
The goal of the operating system is to conserve energy while the computer is working and to put the computer to sleep when it is not working. The decisions that determine how to save energy and when to go to sleep are referred to as the power policy. In OnNow, power policy is based on the end userÆs preferences, the application requirements, and the system hardware capabilities. The implementation of power policy is distributed throughout the system, with different system components acting as policy owners for different aspects. For example, the operating system itself is the policy owner responsible for when the computer should go to sleep, how deep a sleep the computer should go into, and how to operate the processor to obtain energy conservation, and to meet thermal and audible noise goals.
For OnNow systems to be successful, Windows 98 must be aware of how power management features integrate throughout the computer. This is done through the Advanced Configuration and Power Interface (ACPI), which is a system interface that provides a standard way to control power management and Plug and Play functions of the computer hardware. ACPI allows motherboards to describe their device configuration in a way that Windows 98 can understand and automatically turn on and off standard devices, such as CD-ROMs, network cards, hard disk drives, and printers, as well as consumer devices connected to the computer, such as VCRs, TVs, phones, and stereos.
ACPI specification is currently in version 1.0 and has 2 parts: configuration (Plug and Play) and power management. ACPI provides more detailed knowledge to the operating system about what the system can do and what the sources of events are.
For example, the ACPI computer and operating system can do the following:
Make sure the screen does not turn off in the middle of a presentation.
Let the machine wake automatically in the middle of the night to perform some task without needlessly turning on the monitor and drives.
Let the user choose what the power and sleep buttons do in the system.
During Windows 98 setup, ACPI is installed only if the system is a good ACPI system. If your system BIOS was updated to a fully functioning ACPI BIOS, you can manually install ACPI with the following steps:
To install ACPI
1. Flash the BIOS to the newest revision.
2. Run Regedit.
Under the HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Detect, add a String value called ACPIOption and set it to 1.
3. In Control Panel, click Add/Remove Hardware and have it run full detection.
Or, you can enable ACPI support when you setup Windows 98 by using the following line:
setup /p J
Using the OnNow Interface
To monitor OnNow features, use the Power Management icon in the Control Panel to select different Power Schemes.
OnNow includes the following features for Power Management:
1. The ability to start using the system in just a few seconds by using Standby instead of Off. In standby, the monitor and hard disks turn off. When the computer is needed, it comes out of standby much quicker than having to boot the system. ItÆs useful for conserving battery power in portable computers.
2. The ability for the system to put itself in standby automatically when not in use.
3. The ability for the system to automatically wake to handle events, such as running backups, downloading e-mail, and defragmenting your hard disk. This is done through the Task Scheduler.
4. A simplified, single-user interface for power management. Includes a new battery meter, low battery alarms, power control panel, Hibernate, and Standby on the shutdown menu.
5. Enhanced application messaging to allow applications to adjust their behavior appropriately for changes in battery-state.
Windows 98 contains power schemes that configure the system to go on standby, and shut off the monitor after a set time of inactivity.
The following power schemes are built into Windows 98:
Home/Office Desk. For desktop machines. This is installed when you install Windows 98.
Portable/Laptop. Optimized for portable computers. Includes aggressive settings for running on batteries, i.e. drives and display are turned off after shorter lengths of inactivity. If youÆre connected to AC Power, the settings are the same as Home/Office Desk.
Always On. For use with personal servers. It is similar to Home/Office, but has the standby timer disabled and increases the hard disk inactivity timer.
You can change the properties of a built-in scheme or create a new one through the Power Management Properties dialog box in the Control Panel. It contains options to change the timeout periods of your monitor and hard disks.
The dialog box contains additional settings for your laptop system so you can specify different shutdown times for when the computer is running on battery and when it is connected to AC Power. There are also other options pertaining to battery alarms. When battery power reaches a certain level, a box with different options you can choose will be displayed so you can take appropriate actions. You can also display a Power Meter in the taskbar that shows what type of power is being used (battery or AC), and the remaining power left in your batteries.
Some ACPI computers support a feature called Hibernate. This saves everything in your computerÆs memory to the hard disk and shuts it down. You can use this option when youÆll be away from the computer for some time and using a power saving feature will still not give you enough power for extended use. With hibernate, when you turn on the computer, all the programs that you had running will be restored to their previous state.
To use this feature, your laptop must support it. If the tab is not displayed in the Power Management dialog box, then your system does not support it.
