Description of the Different Advanced Power Management States

ID: Q197739

The information in this article applies to:

Microsoft Windows 98

SUMMARY

This article describes the different Advanced Power Management (APM) states.

MORE INFORMATION

The Advanced Power Management (APM) Specification defines four power states:

Ready

Stand-by

Suspended

Three of these states apply both to individual computer components and to your computer as a whole. The suspended state is a special low power condition that applies to your computer as a whole, and not the individual components.

Ready

In the ready state, your computer or device is fully powered up and ready for use. The APM definition of Ready only indicates that your computer or device is fully powered on, it does not differentiate between active and idle conditions.

Stand-by

Stand-by is an intermediate system-dependent state which attempts to conserve power. Stand-by is entered when the Central Processing Unit(CPU) is idle and no device activity is known to have occurred within a specific period of time. Your computer will not return to ready until one of the following events occur:

A device raises a hardware interrupt

Any controlled device is accessed

All data and operational parameters are preserved when your computer is in the Stand-by state.

Suspended

The Suspended state is a computer state which is defined to be the lowest level of power consumption available that preserves operational data and parameters. The suspend state can be initiated by either the system Basic Input Output System (BIOS) or the software above the BIOS. The system BIOS may place your computer into the suspended state without notification if it detects a situation which requires an immediate response such as the battery entering a critically low power state. When your computer is in the Suspended state, computation will not be performed until normal activity is resumed. Resumption of activity does not occur until signaled by an external event such as a button press, timer alarm, and so on.

Off

When in the Off state, your computer or device is powered down and inactive. Data and operational parameters may or may not be preserved in the Off state.

REFERENCES

APM 1.0 Specification, Microsoft Windows 98 Resource Kit

Additional query words: 1.00

Keywords : win98 winapm
Version : WINDOWS:
Platform : WINDOWS
Issue type : kbinfo