Plug and Play
Plug and Play (abbreviated as PnP) is a set of specifications developed by Intel that allows a computer to automatically detect and configure a device and install the appropriate device drivers. With Plug and Play, you can be confident that new devices will work together properly and that your computer will restart correctly after you install or uninstall hardware. Plug and Play also recognizes new hardware when you start your computer and loads any drivers that the hardware device needs.
For example, you can dock a portable computer and connect to a network without changing the configuration. Later, you can undock that same computer and use a modem to connect to the network, again without making any changes to the configuration. Operating system does it for you.
To take full advantage of Plug and Play, you must use an Advanced Configuration and Power Interface (ACPI) computer, running in ACPI mode, and the hardware devices must be Plug and Play. In an ACPI computer the operating system, not the hardware, configures and monitors the computer. The operating system determines which programs are active and manages all of the power requirements for your computer subsystems and peripherals. ACPI lets the operating system direct power to devices as they need it, preventing unnecessary power demands on your system.
Because operating system controls your computer's resources and configuration, you can install Plug and Play hardware devices without restarting the computer. Operating system automatically identifies the new hardware and installs the drivers it needs. If you are using any other type of computer, you may need to perform some setup steps manually and restart your computer when installing new hardware devices.