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A Closer Look at HKEY_LOCAL_MACHINE for Windows NT

HKEY_LOCAL_MACHINE is the handle key that represents the hives that control the system and software. It is independent of the user, and settings made are for all users who log on to the system. Figure A.1 shows the five main keys in HKEY_LOCAL_MACHINE, three of which you have access to.


SAM
(Security Accounts Manager) and SECURITY are part of HKEY_LOCAL_MACHINE, but they are not available for modification by users in the Registry editors. The changes for SAM and
SECURITY
are made through User Manager for Domains, Explorer, and File Manager.

All of the settings in this appendix appear in the following format.

Key Name

Full path=Handle Key\Keyname

Description, specific information, values

Second-Level Key Name

Full path=Handle Key\Keyname\Keyname

Description, specific information, values

Third-Level Key Name

Full path=Handle Key\Keyname\Keyname\Keyname

Description, specific information, values

Additional Level Key Names


Full path=Handle Key\Keyname\Keyname\Keyname\Keyname(\Keyname)

Description, specific information, values

Hardware

HKEY_LOCAL_MACHINE\HARDWARE

This key holds all the keys, subkeys, and values to control all hardware devices with Windows NT. NT does not allow applications to control these devices directly, so the application must know all the information about each device. Also, NT only reads the BIOS information at startup, so that BIOS information must be loaded, too.

Description

HKEY_LOCAL_MACHINE\HARDWARE\DESCRIPTION

This key holds the descriptions for all the devices on the system. In the other parts of the Registry, the devices are listed by device names, driver names, or codes. All of the translations are listed in this key, making it easier for you to use and understand.

System

HKEY_LOCAL_MACHINE\HARDWARE\DESCRIPTION\System

This key holds specifications and information about the system board, system BIOS, and video BIOS, plus subkeys for the processors and bus controllers.

CentralProcessor

HKEY_LOCAL_MACHINE\HARDWARE\DESCRIPTION\System\CentralProcessor

If your system has multiple processors, they are all listed as subkeys under this key. If your system has only one processor, it is listed as processor 0.

HKEY_LOCAL_MACHINE\HARDWARE\DESCRIPTION\System\CentralProcessor\0

This key holds information about the processor, including its manufacturer, description, and rated speed. (And no, you cannot boost the speed of the processor by changing the value!)

FloatingPointProcessor

HKEY_LOCAL_MACHINE\HARDWARE\DESCRIPTION\System\FloatingPointProcessor

A floating-point processor is what is commonly known as a math co-processor. This key holds information regarding it.

HKEY_LOCAL_MACHINE\HARDWARE\DESCRIPTION\System\FloatingPointProcessor\0

Identification and configuration information about the floating-point processor is found in this key.

MultifunctionAdapter

HKEY_LOCAL_MACHINE\HARDWARE\DESCRIPTION\System\MultifunctionAdapter

This key holds information about the BIOS-controlled adapters in the system.

HKEY_LOCAL_MACHINE\HARDWARE\DESCRIPTION\System\
MultifunctionAdapter\0 (PCI)

This key holds information for the configuration of the PCI bus. 32- and 64-bit PCI cards are plugged into this bus. BIOS-supported PCI devices are listed under this key.

HKEY_LOCAL_MACHINE\HARDWARE\DESCRIPTION\System\
MultifunctionAdapter\1 (PNP BIOS)

This key holds the information for the Plug and Play BIOS. Currently, NT does not fully support Plug and Play devices, so no devices are listed under this key.

HKEY_LOCAL_MACHINE\HARDWARE\DESCRIPTION\System\
MultifunctionAdapter\2 
(ISA)

This key holds the information for the ISA (legacy) bus. 16- and 32-bit ISA and VESA cards are plugged into this bus and are listed under this key.

HKEY_LOCAL_MACHINE\HARDWARE\DESCRIPTION\System\MultifunctionAdapter\
2\DiskController

This key holds the settings for the hard- and floppy-disk controllers.

HKEY_LOCAL_MACHINE\HARDWARE\DESCRIPTION\System\MultifunctionAdapter\
2\KeyboardController

This key holds the settings for the standard keyboard controller.

HKEY_LOCAL_MACHINE\HARDWARE\DESCRIPTION\System\MultifunctionAdapter\
2\ParallelController

This key holds the settings for the parallel port controller and installed parallel ports.

HKEY_LOCAL_MACHINE\HARDWARE\DESCRIPTION\System\MultifunctionAdapter\
2\PointerController

This key holds the settings for the mouse port controller.

HKEY_LOCAL_MACHINE\HARDWARE\DESCRIPTION\System\MultifunctionAdapter\
2\SerialController

This key holds the settings for the serial port controller and installed serial ports.

DEVICEMAP

HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP

This key holds the pointers to all the hardware device drivers and settings on the system. It usually points to the control set that is currently on the system.

KeyboardClass

HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\KeyboardClass

This key points to the control set and the driver information listed there, as a map would to a traveler.

KeyboardPort

HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\KeyboardPort

This key points to the control set and the driver information listed there.

PARALLEL PORTS

HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\PARALLEL 
PORTS

This key points to the control set and the driver information listed there.

PointerClass

HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\PointerClass

This key points to the control set and the driver information listed there.

PointerPort

HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\PointerPort

This key points to the control set and the driver information listed there.

SCSI

HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\SCSI

SCSI (Small Computer Systems Interface) is an adapter/device combination that allows tremendous growth and outstanding speed. The settings for all host adapters and devices are listed under this key.

SCSI Port 0 (ATAPI Hard Disk Controller)

HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\SCSI\SCSI Port 0

SCSI Port 0 is the first SCSI host device found in the system, and this key holds the identification and configuration information for it.

HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\SCSI\SCSI Port 0\SCSI Bus 0
HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\SCSI\SCSI Port 0\SCSI Bus 0\
Initiator Id 255
HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\SCSI\SCSI Port 0\SCSI Bus 0\Target Id 0

There are no configurable devices connected to this adapter, so no settings are listed in this key.

HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\SCSI\SCSI Port 0\SCSI Bus 0\Target Id 
0\Logical Unit Id 0

This key holds the settings for the SCSI ID number of the devices attached to the host adapter, and the description of the device.

SCSI Port 1 (ATAPI Floppy-Disk Controller)

HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\SCSI\SCSI Port 1

The floppy-disk controller is also considered a nonconfigurable SCSI device to Windows NT, using an IDE-to-SCSI conversion driver called ATAPI. This key holds all the settings for devices attached to the floppy controller.

HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\SCSI\SCSI Port 1\SCSI Bus 0
HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\SCSI\SCSI Port 1\SCSI Bus 0\Initiator Id 
255
HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\SCSI\SCSI Port 1\SCSI Bus 0\Target Id 0
HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\SCSI\SCSI Port 1\SCSI Bus 0\Target Id 
0\Logical Unit Id 0

SCSI Port 2 (AHA154x)

HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\SCSI\SCSI Port 2

This key is for the settings for the Adaptec 1542c SCSI host adapter, and all the devices connected to it. Figure A.2 shows that there are three devices connected to this host adapter, and each has its own Target ID key below this key.

Device connections to SCSI adapters.

HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\SCSI\SCSI Port 2\SCSI Bus 0
HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\SCSI\SCSI Port 2\SCSI Bus 0\Initiator Id 7
HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\SCSI\SCSI 
Port 2\SCSI Bus 0\Target Id 0

This is the key for the description and settings for the connected hard drive.

HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\SCSI\SCSI Port 2\SCSI Bus 0\Target Id 2

This is the key for the description and settings for the connected scanner.

HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\SCSI\SCSI Port 2\SCSI Bus 0\Target Id 3

This is the key for the description and settings for the connected Syquest removable media drive.

SERIALCOMM

HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\SERIALCOMM

This key lists the names of the installed serial ports.

VIDEO

HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\VIDEO

This key points to the control set and the driver information listed there.

OWNERMAP

HKEY_LOCAL_MACHINE\HARDWARE\OWNERMAP

When a device gives up all control to another, it is said to be owned. Those devices and their owners are listed in this key.

RESOURCEMAP

HKEY_LOCAL_MACHINE\HARDWARE\RESOURCEMAP

This key holds all the basic connection settings for devices on the system, such as IRQ, DMA, and I/O port addresses. They are separated into subkeys, depending on the type of control.

Hardware Abstraction Layer

HKEY_LOCAL_MACHINE\HARDWARE\RESOURCEMAP\Hardware Abstraction Layer

The Hardware Abstraction Layer (HAL) separates the system devices from the software and operating system, ensuring that even in the worst application crashes, the operating system and base hardware continue to run.

The HAL is the way the standard devices are controlled, including parallel and serial ports, disk controllers, and others.

HKEY_LOCAL_MACHINE\HARDWARE\RESOURCEMAP\Hardware Abstraction Layer\PC Compatible Eisa/Isa HAL

This key is the actual type of HAL for the system. There are several types, including PC compatible Eisa/Isa, DEC, MIPS, PowerPC, and Compaq. The values for this key are the actual settings for all the devices.

KeyboardPort/PointerPort

HKEY_LOCAL_MACHINE\HARDWARE\RESOURCEMAP\KeyboardPort/PointerPort

The settings for the keyboard and pointer (PS/2 mouse) port are in this key.

i8042prt

HKEY_LOCAL_MACHINE\HARDWARE\RESOURCEMAP\KeyboardPort/PointerPort\i8042prt

Standard keyboards use an 8042 controller chip. This key holds information about the chip, so the system does not have to read it off the keyboard BIOS.

LOADED PARALLEL DRIVER RESOURCES

HKEY_LOCAL_MACHINE\HARDWARE\RESOURCEMAP\LOADED PARALLEL 
DRIVER RESOURCES

The parallel port drivers in use are listed here.

Parport

HKEY_LOCAL_MACHINE\HARDWARE\RESOURCEMAP\LOADED PARALLEL DRIVER 
RESOURCES\Parport

Settings for the currently active parallel ports are listed in the values in this key. Settings made in Control Panel to change the parallel port name (LPT1, LPT2, and so on) or resources are listed here.

LOADED SERIAL DRIVER RESOURCES

HKEY_LOCAL_MACHINE\HARDWARE\RESOURCEMAP\LOADED SERIAL DRIVER RESOURCES

The serial port drivers in use are listed here.

Serial

HKEY_LOCAL_MACHINE\HARDWARE\RESOURCEMAP\LOADED SERIAL DRIVER RESOURCES\Serial

Settings for the currently active serial ports are listed in the values in this key. Settings made in Control Panel to change the serial port name (COM1, COM2, and so on) or resources are listed here.

OtherDrivers

HKEY_LOCAL_MACHINE\HARDWARE\RESOURCEMAP\OtherDrivers

Other drivers that are not standard for system operations are listed here, so they can be recognized by the system.

Floppy

HKEY_LOCAL_MACHINE\HARDWARE\RESOURCEMAP\OtherDrivers\Floppy

The floppy-drive controller driver settings are listed in this key.

PCI3210

HKEY_LOCAL_MACHINE\HARDWARE\RESOURCEMAP\OtherDrivers\PCI3210

This key lists the settings for a PCI network card.

SCSIAdapter

HKEY_LOCAL_MACHINE\HARDWARE\RESOURCEMAP\SCSIAdapter

SCSI adapters are listed in this key, so specific settings can be made for each one.

Aha154x

HKEY_LOCAL_MACHINE\HARDWARE\RESOURCEMAP\SCSIAdapter\Aha154x

The Adaptec 1542C SCSI host adapter settings are listed in this key.

atapi

HKEY_LOCAL_MACHINE\HARDWARE\RESOURCEMAP\SCSIAdapter\atapi

ATAPI is a driver that translates SCSI-level information for IDE and Enhanced IDE interface cards.

System Resources

HKEY_LOCAL_MACHINE\HARDWARE\RESOURCEMAP\System Resources

Memory and virtual memory settings are listed in this key.

Physical Memory

HKEY_LOCAL_MACHINE\HARDWARE\RESOURCEMAP\System Resources\Physical Memory

Memory that is reserved in the Reserved memory area is listed here.

VIDEO

HKEY_LOCAL_MACHINE\HARDWARE\RESOURCEMAP\VIDEO

Video driver information for current drivers is listed in this key.

s3

HKEY_LOCAL_MACHINE\HARDWARE\RESOURCEMAP\VIDEO\s3

The s3 video driver is the one to be used when the system boots. This key holds the settings for the video card.

VgaSave

HKEY_LOCAL_MACHINE\HARDWARE\RESOURCEMAP\VIDEO\VgaSave

If the video driver is not able to work with the installed video card, the system switches to the driver listed here. The system also uses it if VGA mode is chosen during startup.

VgaStart

HKEY_LOCAL_MACHINE\HARDWARE\RESOURCEMAP\VIDEO\VgaStart

The video driver information actually used during startup is listed here.

SAM

HKEY_LOCAL_MACHINE\SAM

This key is inaccessible from the Registry editors, and it points to information about all the users on the domain.

SECURITY

HKEY_LOCAL_MACHINE\SECURITY

All rights and privileges are included in this Registry setting, but it is inaccessible from the Registry editors.

SOFTWARE

HKEY_LOCAL_MACHINE\SOFTWARE

The settings for all installed 32-bit software and .INI files for applications are listed in this key. The items included vary, depending on the software installed. Control functions for those applications are listed in the many subkeys located here.

SYSTEM

HKEY_LOCAL_MACHINE\SYSTEM

This key stores all information required for the system to start, and for the recovery of the system in case of failure.

Clone

HKEY_LOCAL_MACHINE\SYSTEM\Clone

This subkey is a non-accessible section that holds duplicate information for use by the system in case of failure. This key is saved with RDISK.EXE and activated by Last Known Good, and points to the %SYSTEMROOT%\Repair directory.

ControlSet001

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001

This subkey contains descriptions and controls for device drivers and other services. Multiple sets are created when drivers are changed in the system, and are labeled ControlSet001, ControlSet002, and so on.

Control

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control

This subkey holds the information that is set in the Control Panel applets in Windows NT. Do not edit this information through the Registry editor because some applets make changes in more than one Registry location. A missing entry may cause the system to be unstable. The following list holds the subkeys under the Control key:

BootverificationProgram

Class

ComputerName

CrashControl

FileSystem

GraphicsDrivers

GroupOrderList

hivelist

IDConfigDB

Keyboard Layout

Keyboard Layouts

Lsa

MediaProperties

MediaResources

NetworkProvider

Nls

Print

PriorityControl

ProductOptions

RegistrySizeLimit

SecurePipeServers

SecurityProviders

ServiceGroupOrder

ServiceProvider

Session Manager

Setup

SystemBesources

TimeZoneInformation

Update

VirtualDeviceDrivers

Windows

WOW

Enum

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Enum

Bus enumerator information for Windows NT is added to the Registry during installation of the devices and Windows NT. It is not dynamic, and does not get changed. All the information is required to make NT and its devices start up.

HTREE

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Enum\HTREE

This subkey holds information and pointers to details about devices, including the driver names, based on bus connections. Devices are split between Legacy (ISA) and Plug and Play bus functions.

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Enum\HTREE\ROOT

This subkey simply holds the next subkey.

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Enum\HTREE\ROOT\0

The actual locations of the bus-connected devices and their driver information are listed here.

Root

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Enum\Root

This key contains control information for ISA and PNP bus connections, using the drivers listed next. The information contained in the subkeys in the Root key (shown in the following list) is specifically related to the connection settings and resources:

*PNP030b

*PNP0F03

LEGACY_AFD

LEGACY_AHAl 54X

LEGACY_ASYNCMAC

LEGACY_ATAPI

LEGACY_BEEP

LEGACY_BROWSER

LEGACY_CDFS

LEGACY_CDROM

LEGACY_DISK

LEGACY_EEl6

LEGACY_FASTFAT

LEGACY_FLOPPY

LEGACY_FS_REC

LEGACY_KBDCLASS

LEGACY_KSECDD

LEGACY_LANMANSERVER

LEGACY_LANMANWORKSTATION

LEGACY_LMHOSTS

LEGACY_MESSENGER

LEGACY_MOUCLASS

LEGACY_MSFS

LEGACY_MUP

LEGACY_NBF

LEGACY_NDIS

LEGACY_NDISTAPI

LEGACY_NDISWAN

LEGACY_NETBIOS

LEGACY_NETBT

LEGACY_NETDETECT

LEGACY_NETLOGON

LEGACY_NPFS

LEGACY_NULL

LEGACY_NWLNKIPX

LEGACY_NWLNKNB

LEGACY_NWLNKSPX

LEGACY_PARALLEL

LEGACY_PARPORT

LEGACY_PARVDM

LEGACY_PCI3210

LEGACY_RASACD

LEGACY_RASARP

LEGACY_RASAUTO

LEGACY_RASMAN

LEGACY_RDR

LEGACY_RPCSS

LEGACY_S3

LEGACY_SCSISCAN

LEGACY_SERIAL

LEGACY_SNDBLST

LEGACY_SPOOLER

LEGACY_SRV

LEGACY_TAPISRV

LEGACY_TCPIP

LEGACY_VGASAVE

UNIMODEM5DC8F5BA

Hardware Profiles

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Hardware Profiles

Hardware profiles allow the user to select what hardware will be active after boot. Hardware profiles are normally used for notebooks or other portable systems, where the active/installed hardware may be different. For example, a notebook connected at the office might have a docking station with a network card, a SCSI tape drive, and external monitor and mouse. Different drivers would be required to run that system than when the notebook was detached from these features. Hardware profiles also prevent the system from trying to load all of those drivers when the system is not connected. All controls for hardware profiles are under this key.

0001

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Hardware Profiles\0001

The first set of drivers, shown at startup as the Original Configuration, is listed as profile 0001.

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Hardware Profiles\0001\Software

Software associated with specific devices that may not be connected with another profile is listed here. Software is only listed here if it is affected by another profile.

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Hardware Profiles\0001\System

System information that is unique to profile 0001 is listed here.

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Hardware Profiles\0001\System\
CurrentControlSet
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Hardware Profiles\0001\System\
CurrentControlSet\Control
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Hardware 
Profiles\0001\System\
CurrentControlSet\Enum
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Hardware Profiles\0001\System\
CurrentControlSet\Services

0002

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Hardware Profiles\0002

Profile 0002 is the second profile created for NT. The first (0001) was done during installation. This second profile uses different drivers and settings required for a different hardware setup. The type of information in the following keys mirrors the information that is in hardware profile 0001.

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Hardware Profiles\0002\Software
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Hardware Profiles\0002\System
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Hardware Profiles\0002\System\
CurrentControlSet
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Hardware Profiles\0002\System\
CurrentControlSet\Control
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Hardware Profiles\0002\System\
CurrentControlSet\Enum
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Hardware Profiles\0002\System\
CurrentControlSet\Services

Current

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Hardware Profiles\Current

This key contains the profiles that are actually current in the system. The choice made during startup affects which of the two (or more) hardware profiles is current. For example, if Profile 0002 is chosen, all of the Profile 0002 information will be mapped into these keys.

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Hardware Profiles\Current\Software
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Hardware Profiles\Current\System
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Hardware Profiles\Current\System\
CurrentControlSet
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Hardware Profiles\Current\System\
CurrentControlSet\Control
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Hardware Profiles\Current\System\
CurrentControlSet\Enum
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Hardware Profiles\Current\System\
CurrentControlSet\Services

Services

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services

This key contains all the standard services that come with Windows NT, plus any that have been added through the installation of services or devices. Each standard Services key (shown in the following list) contains configuration and identification settings.

Abiosdsk ClipSrv Jazzg300

Afd Cpqarray Jazzg364

Aha154x cpqfws2e Jzvxl484

Aha174x dac960nt Kbdclass

aic78xx dce376nt KSecDD

Alerter Dell_DGX LanmanServer

Always Delldsa LanmanWorkstation

ami0nt DHCP LmHosts

amsint Disk Messenger

Arrow Diskperf mga

AsyncMac DptSCSI mga_mil

AsyncMac3 dtc329x mitsumi

atapi et4000 mkecr5xx

Atdisk EventLog Modem

ati Fastfat Mouclass

Beep Fd16_700 Msfs

Browser Fd7000ex Mup

BusLogic Fd8xx Nbf

Busmouse flashpnt Ncr53c9x

Cdaudio Floppy ncr77c22

Cdfs Fs_Rec Ncrc700

Cdrom Ftdisk Ncrc7l0

Changer i8042prt NDIS

cirrus Inport NdisTapi

NdisWan Pcmcia Sparrow

NdisWan2 PlugPlay Spock

NdisWan4 pnpisa Spooler

NdisWan5 psidisp symc810

NdisWan6 0I10wnt T128

NetBIOS qv T13B

NetBIOSInformation RasAcd TapiSrv

NetBT RasArp Tcpip

NetDDE RasAuto tga

NetDDEdsdm RasMan tmv1

NetDetect Rdr Ultral24

Netlogon RemoteAccess Ultra14f

Npfs Replictor Ultra24f

Ntfs RPCLOCATOR UPS

NtLmSsp RpcSs v7vrarn

Null s3 VgaSave

NwlnkIpx Schedule VgaStart

NwlnkNb SCSIprnt Wd33c93

NwlnkSpx SCSIscan wd90c24a

Oliscsi Serial wdvga

Parallel Sermouse weitekp9

Parport Sfloppy WinSock

ParVdm Simbad WinSock2

PCI3210 slcd32 WinTrust

PCI32101 sndblst Xga

PCIDump SNMP

ControlSet002

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet002

When drivers are changed, if no other control set has the same drivers and information, an additional one is created with an incremental number such as ControlSet002. If a control set with the same drivers exists, that one is used instead.

CurrentControlSet

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet

The control set (listed previously) currently in use is mapped into all the keys listed next at startup. See Figure A.3 for an example.

Figure A.3. The control set used is mapped to CurrentControlSet.

Control

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control

This is mapped information from a specific control set (such as ControlSet001).

Enum

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum

This is mapped information from a specific control set (such as ControlSet001).

Hardware Profiles

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Hardware Profiles

This is mapped information from a specific control set (such as ControlSet001).

Services

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services

This is mapped information from a specific control set (such as ControlSet001).

Select

HKEY_LOCAL_MACHINE\SYSTEM\Select

This key lists the current control set, which is saved as Last Known Good. This key also lists which control sets, if any, failed during startup.

Setup

HKEY_LOCAL_MACHINE\SYSTEM\Setup

This key lists the system partition, the setup status, and other information about the setup process for the system.

Summary

HKEY_LOCAL_MACHINE holds all the filename, file-location, and setting information for the entire system, and all its attached devices. It is updated by the Control Panel, by the installation of devices, and through utilities such as Windows NT Diagnostics. HKEY_LOCAL_MACHINE is protected by Last Known Good and the Emergency Repair Disk because of the critical nature of the contained Registry settings.

Disclaimer: Modifying the registry can cause serious problems that may require you to reinstall your operating system. We cannot guarantee that problems resulting from the incorrect use of the registry can be solved. Use the information provided at your own risk.

   

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