Windows 98 Does Not Support ACPI Passive Cooling Mode (189091)
The information in this article applies to:
This article was previously published under Q189091 SUMMARY
Windows 98 does not provide support for Passive Cooling Mode as described
in the Advanced Configuration and Power Interface (ACPI) specification.
Windows 98 only supports Active Cooling Mode.
MORE INFORMATION
The ACPI specification defines two categories of methods for cooling
computer systems:
- Active cooling methods
- Passive cooling methods
Active cooling methods may include turning on one or more fans to provide
increased airflow and improve dissipation of heat from active components.
these methods cool the computer without decreasing its performance, but
increase power consumption and often increase noise production.
Passive cooling methods may include slowing down (throttling) the
computer's central processing unit (CPU) so that the CPU generates less
heat. These methods tend to decrease power consumption, but decrease
overall system performance when used.
A computer which complies with the ACPI specification may operate in one
of two cooling modes:
- Active Cooling mode
- Passive Cooling mode
In Active Cooling mode, the computer first uses active cooling methods to
control the temperature of the computer. If the computer's temperature
continues to rise when the active cooling methods are in use, then the
computer uses passive cooling methods to cool overheated components.
In Passive Cooling mode, the computer first uses passive cooling methods
to control the temperature of the computer. If the computer's temperature
continues to rise when the passive cooling methods are in use, then the
computer uses active cooling methods to cool overheated components.
In either cooling mode, if the temperature continues to rise to critical
levels, the computer may shut down or go to some other non-operating,
lower-power state. This is to help prevent thermal damage to components.
The computer's cooling mode is controlled by the temperature set point.
This is the temperature at which each cooling method is activated. For
example, if the set point for the active cooling method is a lower
temperature than the set point for the passive cooling method, then the
active method is employed first, and the computer goes to Active Cooling
mode. If the set point for the passive cooling method is lower than the
set point for the active cooling method, then the passive method is
employed first, and the computer goes to Passive Cooling mode.
Windows 98 configures the computer to operate only in Active Cooling mode,
and does not provide an interface for changing the active and passive
cooling set points so that the computer could be reconfigured to operate
in Passive Cooling mode.
For more information, please see the following article in the Microsoft
Knowledge Base:
ARTICLE-ID: 189803
TITLE : PRB: PMPI FanThrottleToleranceAc/Dc Not Implemented Under Win98
REFERENCES
Information on ACPI specifications and implementation can be found at the
following Internet location:
The third-party contact information included in this article is provided
to help you find the technical support you need. This contact information
is subject to change without notice. Microsoft in no way guarantees the
accuracy of this third-party contact information.
Active and passive cooling methods and modes are discussed in the ACPI
specification, Revision 1.0, December 22, 1996, in section 12, "Thermal
Management".
| Modification Type: | Minor | Last Reviewed: | 12/16/2004 |
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| Keywords: | kbinfo kbPowerMan KB189091 |
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