Microsoft KB Archive/250534

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Description of Plug and Play Components within the HKEY_LOCAL_MACHINE\Enum\Bios Subkey

Article ID: 250534

Article Last Modified on 1/27/2007


  • Microsoft Windows Millennium Edition
  • Microsoft Windows 98 Standard Edition
  • Microsoft Windows 98 Second Edition
  • Microsoft Windows 95

This article was previously published under Q250534


This article describes the Plug and Play subkey and the components of the following registry key in a Windows Me/98/95-based computer:



The following subkey contains entries for Plug and Play components of the Basic Input/Output System (BIOS), including timers, controllers, DMA chips, and so on:


The following list includes a value name, followed by an appropriate description:

PNP0000-PNP0004    Interrupt controllers

PNP0100-PNP0102    System timers

PNP0200-PNP0202    DMA controllers

PNP0300-PNP0313    Keyboard controllers

PNP0400-PNP0401    Printer ports

PNP0500-PNP0501    Communication ports

PNP0600-PNP0602    Hard disk controllers

PNP0700            Standard floppy disk controller

PNP0800            System speaker

PNP0900-PNP0915    Display adapters

PNP0A00-PNP0A04    Expansion buses

PNP0B00            CMOS real-time clock

PNP0C01            System board extension for Plug and Play BIOS

PNP0C02            Reserved

PNP0C04            Numeric data processor

PNP0E00-PNP0E02    PCMCIA controllers

PNP0F01            Serial Microsoft mouse

PNP0F00-PNP0F13    Mouse ports

PNP8xxx            Network adapters

PNPA030        Mitsumi CD-ROM controller

PNPB0xx            Miscellaneous adapters


Plug and Play codes are grouped in classes according to their four-digit code. You can view and modify the device configuration used on your computer with Device Manager.

Detection and enumeration are the two processes that Windows uses to configure devices. Detection is the process Windows uses during its search for legacy or non-Plug and Play devices on a computer. Detection is used during Windows Setup and any time you use the Add New Hardware Wizard to search for new hardware installed in your computer. Detection does not run each time you start Windows. During the detection process, Windows creates a log file named Detlog.txt in the root folder of the boot drive. This file is commonly referenced when troubleshooting problems with hardware detection.

Enumeration is the process Windows uses to identify Plug and Play devices in your computer, including those devices on Plug and Play buses, such as ISAPNP, PCI, and PC Card (PCMCIA) devices. Enumeration occurs each time Windows starts and whenever Windows receives notification that a change has occurred in the computer hardware configuration, such as when you remove a PC Card.

Additional query words: scanregw scanreg

Keywords: kbenv kbinfo KB250534