Power Plans, Sleep Modes, and Shutdown
Normally, computers running Windows 8 use
the Balanced power plan, and this power plan turns off the display and
puts the computer in sleep mode automatically after a specified period of time passes with no user activity.
When entering the sleep state, the
operating system automatically saves all work, turns off the display,
and puts the computer in sleep mode. Sleep mode is a low-power
consumption mode in which the state of the computer is maintained in the
computer’s memory, and the computer’s fans and hard disks are turned
off.
Windows 8 saves the computer state
before entering sleep mode, and you don’t need to exit programs before
you do this. Because the computer uses very little energy in the sleep
state, you don’t have to worry about wasting energy.
Tip
Sleep mode works in slightly different ways
depending on the type of computing device. Often you can turn off and
turn on mobile computers by closing or opening the lid. When you close
the lid, the laptop enters the sleep state. When you open the lid, the
laptop wakes up from the sleep state. If the laptop is in the sleep
state for an extended amount of time, or the laptop’s battery runs low
on power, the state of the computer is saved to the hard disk and then
the computer shuts down completely. This final state is similar to the hibernate state used in early releases of Windows.
To view or modify the default power
options, open Control Panel. In Control Panel, tap or click System And
Security, and then, under Power Options, tap or click Change When The
Computer Sleeps. The options available depend on the type of computing
device. With mobile computers and tablets, as shown in Figure 4,
you may be able to set On Battery and Plugged In options for dimming
the display, turning off the display, putting the computer to sleep,
and adjusting the display brightness. With desktop computers, you can
only specify when the display is turned off and when the computer goes
to sleep. Tap or click Save Changes to save your changes.
You can cause most computers to enter the
sleep state by tapping or clicking the Settings charm button, tapping or
clicking Power, and then tapping or clicking Sleep. To wake the
computer from the sleep state, you can press and hold somewhere on the
touch screen, move the mouse, or press any key on the keyboard. Note
that some computers have separate power and sleep buttons on their case.
The way these buttons work can be set through the power plan options.
There are instances in which a computer can’t
use the sleep state. The system hardware, state, and configuration can
affect the way the power and sleep buttons work. Some computer hardware
doesn’t support the sleep state. In this case, the computer can’t use
the sleep state. This is also the case when the computer has updates
installed that require a restart or you’ve installed programs that
require a restart. Additionally, if an administrator has reconfigured
the power options on the computer and set the power button, the sleep
button, or both to alternative actions, the computer will use those
actions instead of the default shutdown and sleep actions.
Caution
When working with computers in the sleep state, keep in mind that the computer is still drawing power.
You should never install hardware inside the computer when it is in the
sleep state. To avoid possible confusion regarding the sleep state and
the power off state, be sure to unplug desktop computers running Windows
8 before installing internal devices. External devices are exceptions.
You can connect USB, FireWire, and eSATA devices without shutting down
the computer.
To change the default setting for the power
button, open Control Panel. In Control Panel, tap or click System And
Security, and then, under Power
Options, tap or click Choose What The Power Buttons Do. As before, the
options available depend on the type of computing device. With mobile
computers, as shown in Figure 5,
you may be able to set On Battery and Plugged In options that specify
what happens when you press the power button, what happens when you
press the sleep button, and what happens when you close the lid.
Optionally, you can tap or click Change Settings That Are Currently
Unavailable, and then do any of the following:
-
Select Require A Password to require a password to log on after waking the computer from sleep.
-
Select Turn On Fast Startup to save system
information to a file on the system disk when you shut down the
computer. This file is then read during boot to enable faster startup.
When you restart a computer, Fast Startup is not used.
-
Select the Power options you want displayed when you click Power.
Save your changes by tapping or clicking Save Changes.
