PnP (Plug and Play) in PCI (Peripheral Component Interconnect) Bus

Plug and Play (PnP) is a concept that means one can connect a device into a computer and it is automatically identified, recognized and configured to work in that system.

To be fully implemented, PnP needs three things.

1. PnP BIOS: PnP BIOS enables PnP and detects PnP devices. The BIOS also reads the ESCD (Extended System Configuration Data) for configuration information on existing PnP devices.
2. Extended System Configuration Data (ESCD): It is a file that contains information for installed PnP devices.
3. PnP operating system: Any operating system, such as Windows XP, that supports PnP complete the configuration process started by the BIOS for each PnP devices.

PnP automated several key tasks:

1.  Interrupt Requests (IRQ): It is a hardware interrupt, used by various parts of a computer to get attention of a computer system.
2. Direct Memory Access (DMA): It helps the device to access system memory without consulting the CPU first.
3. Memory Addresses: It ensures that the hardware needs resources to operate properly.
4. Input/Output (I/O) configuration: It defines the ports for receiving and sending data/information.