TITLE
    Energy Saver Control Panel: Sleep and Power Management (5/96)
Article ID:
Created:
Modified: 		18633
9/22/95
5/17/96
TOPIC


    This article provides details about the "Sleep" and power management functions of the Energy Saver control panel shipping with the Power Macintosh 7200, 7500, and 8500 series computers.

    Questions answered in this article:

    1) Is the central processing unit (CPU) still responsive when the Energy Saver control panel spins down the hard drive in sleep mode?

    2) Is it possible to spin down the hard drive, but not put the monitor into sleep mode?

    3) Can the Energy Saver control panel spin down any hard drive attached to the SCSI bus, or only the startup disk?

    4) When does the Energy Saver control panel begin the countdown before putting the computer to sleep or shutting down? Is there a specified delay, or does the countdown begin as soon as the computer is idle?

    5) If my computer is in sleep mode, and a fax call comes in (assuming the fax software is set to receive faxes), does my computer wake up and receive the fax?

DISCUSSION


    1) Question: Is the central processing unit (CPU) still responsive when the Energy Saver control panel spins down the hard drive in sleep mode?

    Answer: While in sleep mode, the CPU responds to mouse, keyboard, and serial port activity. If an activity requires disk access, the hard drive is spun up.


    2) Question: Is it possible to spin down the hard drive, but not put the monitor into sleep mode?

    Answer: Yes, it is possible for the hard drive to spin down even though the monitor is not in sleep mode. When the hard drive is spun down, the arrow is unresponsive (as if the system is frozen), but hitting a key spins the hard drive back up. However, there is a delay before the drive spins back up, and there is no notification to the user that the drive is spinning back up.


    3) Question: Can the Energy Saver control panel spin down any hard drive attached to the SCSI bus, or only the startup disk?

    Answer: The Energy Saver control panel may or may not spin down all hard drives attached to the SCSI bus. Apple has not tested The ability to spin down a hard drive is dependent on the formatting software used on the hard drive. In limited testing, the Energy Saver control panel has spun down external drives formatted with Drive Setup.


    4) Question: When does the Energy Saver control panel begin the countdown before putting the computer to sleep or shutting down? Is there a specified delay, or does the countdown begin as soon as the computer is idle?

    Answer: The countdown to shutdown or sleep begins as soon as the computer is idle. Your computer is idle if when all of the following conditions are met:

    - No Apple Desktop Bus (ADB) routines other than routine monitoring of the
    bus
    - No Input/Output (I/O) calls to firmware (Read, Write, Control, Format,
    Status)
    - No changes in the cursor (for example, the rotation of a hand in the
    clock icon)
    - No post-event calls (for example, a call resulting from insertion of a
    disk)
    - No communication through the serial port


    5) Question: If my computer is in sleep mode, and a fax call comes in (assuming the fax software is set to receive faxes), does my computer wake up and receive the fax?

    Answer: A modem that uses the serial port's 'wake on ring' pin setting, and that has software that reads it, can wake the CPU from sleep. The GeoPort Telecom Adapter from Apple features this capability. Depending on background activity, some fax software may keep the CPU busy and not allow the computer to enter "sleep" mode.


    Article Change History:
    16 May 1996 - Revised modem information.
    08 Jan 1996 - Changed distribution status.




Document Information
Product Area: Mac OS System Software
Category: General OS
Sub Category: General Topics

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