REGISTRY

The Registry is the heart and soul of Microsoft Windows XP and can be called as “building block of OS” .

Simply put, the registry is nothing more than your computer's settings.

Lineage of registry

MS−DOS

Every application that ran on MS−DOS was responsible for managing its own settings.

Microsoft Windows 3.0

This version provided INI files for storing settings. Every application had its own INI files.

Windows 3.1

Registry was introduced as a tool for storing OLE (object linking and embedding) settings.

And Windows 95 & Windows NT 3.5 expanded the registry to the configuration database that

Windows XP uses now.

Some of its main functions

I. The registry contains the configuration data that makes the operating system work.

II. It enables you to customize Windows XP in ways you can't through the user interface.

III. The registry enables developers to organize configuration data in ways that are impossible with INI

files.

IV. Windows XP and every application that runs on Microsoft's latest desktop operating system do

absolutely nothing without consulting the registry first.

V. For each and every double−click , Windows XP consults the registry to figure out what to do with it.

VI. When a device is installed , Windows XP assigns resources to the device based on information in the

registry and then stores the device's configuration in the registry.

VII. When an application such as Microsoft Word 2002 is being run , the application looks up your

preferences in the registry.

This built-in facility of Microsoft Windows Xp is used by,

Power users

IT professionals

Registry is a great paradox .On the one hand, it's the central place for all of Windows XP's configuration data. On the other

hand, the fact that the registry is so critical, also makes it one of the operating system's weaknesses. If the registry fails,

Windows XP fails.

Getting started

1. Click on Start button

2. Then on Run from menu

3. Run dialogue box will appear

4.In the Open text box type the command “regedit” or “regedt32.exe”

Structure of registry

The structure of Windows XP's registry is so similar to the structure of its file system

In the editor's left pane, which is called the key pane, just as Windows Explorer's left pane. Each folder in the key pane

is a registry key.

In the editor's right pane, which is called the value pane, you see a key's values.

Basics of Registry

Keys

Keys are so similar to folders (Registry Editor even uses the same icon for keys as Windows Explorer uses for folders)

that they have the same naming rules.

A key's name is limited to 256 Unicode characters, and you can use any ASCII character in the name other than a

backslash (\), asterisk (*), and question mark (?).

In addition, Windows XP reserves all names that begin with a period for its own use.

Root keys

HKEY_CLASSES_ROOT

HKEY_CURRENT_USER

HKEY_LOCAL_MACHINE

HKEY_USERS

HKEY_CURRENT_CONFIG

Values-

Each key contains one or more values.

A value's name is similar to a file's name.

A value's type is similar to a file's extension, which indicates its type.

A value's data is similar to the file's actual contents.

Parts of a value

Name

Every value has a name.

up to 256 Unicode characters except for the backslash (\), asterisk (*), and question mark (?), with Windows XP

reserving all names that begin with a period.

Type

Each value's type determines the type of data that it contains.

For example, a REG_DWORD value contains a double-word number, and a REG_SZ value contains a string.

Data

Each value can be empty or null or can contain data.

A value's data can be a maximum of 32,767 bytes, but the practical limit is 2 KB.

Default value

Default value is almost always a string type.

In most cases, the default value is null.

Types of data

Windows XP supports the following types of data in the registry. As you look through this list, realize that REG_BINARY,

REG_DWORD, and REG_SZ account for the vast majority of all the settings in the registry:

REG_BINARY

REG_DWORD

REG_DWORD_BIG_ENDIAN

REG_DWORD_LITTLE_ENDIAN

REG_EXPAND_SZ

REG_FULL_RESOURCE_DESCRIPTOR

REG_LINK

REG_NONE

REG_QWORD

REG_QWORD_BIG_ENDIAN

REG_QWORD_LITTLE_ENDIAN

REG_RESOURCE_LIST

REG_RESOURCE_REQUIREMENTS_LIST

REG_SZ

HKEY_CURRENT_USER

Contains the root of the configuration information for the user who is currently logged on. The users folders, screen colors

and control panel settings are stored here. This information is referred to as a users profile.

HKEY_USERS

Contains the root of all user profiles on the computer. HKEY_CURRENT_USER is a sub-key of HKEY_USERS.

HKEY_LOCAL_MACHINE

Contains the configuration particular to the computer (for any user).

HKEY_CLASSES_ROOT

It is sub-key of HKEY_LOCAL_MACHINE\SOFTWARE. The information stored here ensures that the correct program opens

when you open a file by using windows explorer.

HKEY_CURRENT_CONFIG

Contains information about the hardware profile used by the local computer at system startup.

Using registry editor and customizing your computer

Disable right click

Disable Run from start menu

Disable Volume

Disable Control panel

Creating a System key

Disable Appearance tab

Disable Settings tab

Disable Screen saver tab

Disable Password changing

Registry management tools

Hundreds of third−party and shareware registry tools are available. You learn about many of them throughout this book.

Some tools I use more often than others, though, and here's an introduction to them:

Registry Editor

This is the primary tool you use to edit settings in the registry.

Console Registry Tool for Windows (Reg.exe)

This command−line registry tool supports most of the capabilities of Registry Editor. The significance of this tool

is that it allows you to script edits in batch files.

WinDiff

This tool comes with the Windows XP Support Tools, which you install from \Support\Tools on the Windows XP

CD.

Most of the Windows 2000 Resource Kit tools still work well in Windows XP, and you can download many of them

from Microsoft's Web site at http://www.microsoft.com/windows2000/techinfo/reskit/tools/default.asp.