Microsoft KB Archive/256902

= Saving Data While Running a Windows 2000-Based Computer on Battery Power =

Article ID: 256902

Article Last Modified on 2/19/2007

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APPLIES TO


 * Microsoft Windows 2000 Server
 * Microsoft Windows 2000 Advanced Server
 * Microsoft Windows 2000 Professional Edition

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This article was previously published under Q256902



SYMPTOMS
Unsaved application data may be lost if your computer completely loses power or if you leave your computer unattended/idle for a long period of time.



CAUSE
You can lose unsaved data for any of the following reasons:
 * A power or system failure may cause the computer to shut down while program(s) with unsaved data are running.
 * Computers in Standby mode while running on battery power for an extended period of time eventually lose power and shut down (and any unsaved application data is lost).
 * Windows 2000 does not support "wake on low battery" or wake events from battery devices. This can potentially cause problems for the following reasons:
 * The battery is drained to low levels while in a manually requested Standby mode (Shutdown menu, lid is closed, Power button, and so on). The low and critical battery alarms are not triggered unless the computer is active and running when the battery alarm level is reached, regardless of the power management and system BIOS support settings. Computers in Standby mode while running on battery power for an extended period of time eventually lose power and shut down (and any unsaved application data is lost).
 * Computer enters Standby mode through a system idle timeout, but does not have power management or system BIOS support settings to wake the system after it enters Standby mode and then enter Hibernate mode.



RESOLUTION
Use the following recommendations to avoid losing unsaved application data when the computer experiences power failure, system failure, or enters a power-saving mode:
 * Save data often.

In general, it is a good idea to save data often, regardless if your computer is running on battery or AC power. Many programs, such as Microsoft Office, have the option to periodically save a copy of the document for this purpose.
 * Save data before leaving the computer unattended.

As part of a good practice to save data often, you should save data before leaving the computer idle for extended periods of time.
 * Save data before entering Standby or Sleep modes.

Standby and Sleep modes save the state of the system into physical memory before the computer enters a non-off state. This is primarily designed to conserve power while the computer is not in use or has become idle, but the physical memory is dependent on an uninterrupted power source.
 * Save data before leaving a power management-enabled computer unattended.

Most computers with Windows 2000 power management enabled detect when the computer has been sitting idle and would benefit from a reduction in the system power usage. Most computers are configured to enter a power-saving mode by default.
 * Configure the computer power management settings to enter Hibernate mode.

This saves the state of the system to the primary mass storage device, especially whenever you leave the computer in Standby mode for an extended period of time. For information on system power management settings, click Start, click Help, click Contents, double-click Control Panel, and then double-click Power Options.
 * Set the first system idle timeout event to Hibernate.

If the computer automatically enters a power-saving mode when it is left unattended/idle for the specified period of time, the computer enters Hibernate mode (instead of Standby) and saves the system state to the primary mass storage device. Depending on the level of system BIOS support, you can set the first system idle timeout to Standby and the second system idle timeout to Hibernate (the computer wakes from Standby and enters Hibernate in this configuration). For information on system power management settings, click Start, click Help, click Contents, double-click Control Panel, and then double-click Power Options.
 * Configure the system battery alarms to enter Hibernate mode (when applicable).

Battery alarms are triggered when battery power reaches the designated level (for example, low, critical, or both). Setting the battery alarms to Hibernate saves the system state to the primary mass storage device. For information on system power management settings, click Start, click Help, click Contents, double-click Control Panel, and then double-click Power Options.



Power Management Terminology

 * Advanced Configuration Power Management Interface (ACPI): This is a new method.
 * Advanced Power Management (APM): This is the old method.
 * Standby: System state is saved to physical memory before system enters a power-saving mode.
 * Hibernate: System state is saved to the primary mass storage device before the system enters shutdown.
 * System Idle Timeout: Possible primary and secondary timer settings, defined in the Power Options tool in Control Panel, to trigger power management events when the timer levels are reached.
 * Battery Alarms: Settings for low and critical battery percentage levels that trigger defined power management events (either Standby or Hibernate) when those levels are reached.
 * System BIOS Support: Not every system can perform even the most basic of power management functions. Please refer to the system documentation to make sure your system supports either the ACPI or APM standard. If your system BIOS does not support ACPI or APM, the references to power management in this document do not apply.

If your system only supports APM, it cannot perform any of the automatic wake functions defined through the secondary system idle timeout.

Keywords: kbenv kbinfo KB256902

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