Power Management; Power Management Modes - Acer Extensa 500 Service Manual

Power Management

This computer has a built-in power management unit that monitors system
activity. System activity refers to any activity involving one or more of the
following devices: keyboard, mouse, floppy drive, hard disk, peripherals
connected to the serial and parallel ports, and video memory. If no activity is
detected for a period of time (called an inactivity time-out), the computer
stops some or all of these devices in order to conserve energy.
This computer manages its power according to the way you use your
computer. This means the computer delivers maximum power when you
need it, and saves power when you don't need the maximum — all without
your intervention. There are no timers to set, because the power
management system figures out everything for you.

Power Management Modes

Display Standby Mode
Screen activity is determined by the keyboard the built-in touchpad, and an
external PS/2 pointing device. If these devices are idle for the period
determined by the computer's power management system, the display shuts
off until you press a key or move the touchpad or external mouse.
"Automatic Dim" Feature
The computer has a unique "automatic dim" power-saving feature. When the
computer is using AC power and you disconnect the AC adapter from the
computer, it automatically dims the LCD backlight to save power. If you
reconnect AC power to the computer, it automatically adjusts the LCD
backlight to a brighter level.
Hard Disk Standby Mode
The hard disk enters standby mode when there are no disk read/write
operations within the period of time determined by the power management
system. In this state, the power supplied to the hard disk is reduced to a
minimum. The hard disk returns to normal once the computer accesses it.
System Standby Mode
The computer consumes very little power in Standby mode. Data remain
intact in the system memory until the battery is drained.
There is one necessary condition for the computer to enter Standby mode:
Heuristic Power Management Mode must be set to [ENABLED].
There are four ways to enter Standby mode:
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System Introduction