Microsoft KB Archive/96560

= POWER.EXE and Advanced Power Management (APM) Support =

Article ID: 96560

Article Last Modified on 11/19/1999

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APPLIES TO


 * Microsoft MS-DOS 6.0 Standard Edition
 * Microsoft MS-DOS 6.2 Standard Edition
 * Microsoft MS-DOS 6.21 Standard Edition
 * Microsoft MS-DOS 6.22 Standard Edition

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This article was previously published under Q96560



SUMMARY
You can install the Power program (POWER.EXE) even if your BIOS does not support the Advanced Power Management (APM) specification. After you install POWER.EXE in the CONFIG.SYS file, the POWER command (without any switches) provides status information.

On systems without APM support, POWER displays the following:   Power Management Status ---  Setting = ADV:REG CPU: idle 90% of the time On systems with APM support, POWER displays the following additional information reported by the BIOS:   Power Management Status ---  Setting = ADV:REG CPU: idle 90% of the time AC Status: OFFLINE Battery status: High Battery life (%): 90



MORE INFORMATION
POWER.EXE detects whether your system has an APM-compliant BIOS and then adapts accordingly.

When POWER.EXE detects that your system is idle, it saves power by issuing a CPU HALT instruction. HALT stops CPU execution until the next hardware interrupt occurs (this is usually the timer interrupt, which occurs 52 times per second). On systems without an APM-compliant BIOS, testing reveals a 5% power savings.

If your system has an APM-compliant BIOS, POWER.EXE communicates with the BIOS. Depending on the frequency of the idle signals from POWER, the APM-compliant BIOS can save power by shutting down the display or hard disk, switching the processor to a slower speed, or suspending the system entirely.

Additional query words: 6.22 6.00 five percent 6.20

Keywords: KB96560

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