The BIOS is one of the four major parts of the system whose cooperation is required in order to implement Plug and Play features on a PC. In short, Plug and Play (also called "PnP" for short) is a system whereby your PC hardware, BIOS and operating system work together to identify and configure resource usage by hardware devices automatically. The intention is to reduce the number of resource conflicts, jumper settings, and manual driver setups required to get the system to work.

The BIOS is a key part of this; in fact it does much of the work of identifying and configuring expansion cards, and passing configuration information on to the operating system.