Overview
To shut down or power off a computer is to remove power from a computer's main components in a controlled way. After a computer is shut down, main components such as CPUs, RAM modules and hard disk drives are powered down, although some internal components, such as an internal clock, may retain power.
Implementations
The shutdown feature and command is available in Microsoft Windows, ReactOS, HP MPE/iX, and in a number of Unix and Unix-like operating systems such as Apple macOS.
Microsoft Windows and ReactOS
In Microsoft Windows and ReactOS, a PC or server is shut down by selecting the item from the Start menu on the desktop. Options include shutting down the system and powering off, automatically restarting the system after shutting down, or putting the system into stand-by mode.
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