TITLE
    PowerBook: When Application Processing Slows Down
Article ID:
Created:
Modified: 		10614
8/18/92
5/8/98
TOPIC

    I'm using some mathematics software on the PowerBook 170. When the application is processing an equation and plotting the results on the screen, the system slows down, then halts screen plotting. Moving the trackball seems to "wake up" the system, and plotting continues. This occurs whether the unit is plugged in or under battery power.

    Is this a known problem, and is there a workaround?

DISCUSSION

    The power consumption of the PowerBook's microprocessor is reduced automatically when it detects that no activity requiring its attention has taken place for a period of time. This feature is called "system rest" in System 7.0; it is called "processor cycling" in System 7.0.1 or later.

    The microprocessor comes back up to speed instantaneously when you resume using the computer. You don't need to do anything for system rest or processor cycling to take effect. But this may be the cause of your problems. Try turning off system rest or processor cycling while using the program.


    To turn off system rest in System 7.0.1 (using the Portable control panel):
      1. Choose Control Panels from the Apple menu, and open the Portable control panel.
      2. Hold down the Option key while clicking "Minutes Until Automatic Sleep."
      3. Click Don't Rest.
      4. Click OK.


    To turn off processor cycling in System 7.1 to 7.1.2
      1. Choose Control Panels from the Apple menu, and open the PowerBook control panel.
      2. Hold down the Option key on the keyboard and click the Options button.
      3. Click "Don't allow cycling."
      4. Click OK.

    Important: To conserve power most efficiently, turn off system rest or processor cycling only when using a program that interferes with this feature. Turn system rest or processor cycling back on again as soon as possible. This feature is turned back on automatically the next time you choose Restart or Shut Down.


    To turn off processor cycling under Sytem 7.5 to Mac OS 8.0 (not using Energy Saver for PowerBook Conservations):
      1. Choose Control Panels from the Apple menu, and open the PowerBook control panel
      2. Make sure the switch is set to Easy
      3. Hold down the Option key on the Keyboard and move the switch to Custom
      4. Uncheck - Allow processor cycling-more battery savings.

    Article Change History:
    03 Apr 1995 - Reviewed for technical accuracy.
    16 Aug 1993 - Added changes in terminology as of System 7.1.

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