What Is Windows Registry

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∟Windows Registry Key and Value Management Tools

∟What Is Windows Registry

This section provides a quick introduction on the Windows registry and related concepts like registry key, registry value name, type, and data.

What is the Windows Registry? According to the Microsoft dictionary, the Registry is a central hierarchical database used in Microsoft Windows systems to store information that is necessary to configure the system for one or more users, applications and hardware devices. The Registry contains information that Windows continually references during operation, such as profiles for each user, the applications installed on the computer and the types of documents that each can create, property sheet settings for folders and application icons, what hardware exists on the system, and the ports that are being used.

But here is my understanding: The Windows registry is a simple database used by Windows systems to store operating system information application program information. More precisely, The Windows registry contains:

Information and settings for all hardware devices.
Information and settings for all operating system components.
Information and settings for any application programs that want to use it.
Runtime information of the operating system kernel.

Information in the Windows registry is organized in a tree structure using the following concepts:

A Registry Key - A node in the registry tree. A registry key may have registry values and next level registry keys.
A Registry Value - A record associated with a registry key to store the information with 3 fields: Name, Type, and Data.
A Registry Value Name - A field of a registry value to store the name of the value.
A Registry Value Type - A field of a registry value to store the type of the value.
A Registry Value Data - A field of a registry value to store the data of the value.

For example, the Microsoft FreeCell game program uses the Windows registry to store multiple registry values. One of them is called "wins" and associated to a registry key called "FreeCell" under several parent registry keys:

HKEY_CURRENT_USER - 1st level key
   Software - 2nd level key
      Microsoft - 3rd level key
         Windows - 4th level key
            CurrentVersion - 5th level key
               Applets - 6th level key
                  FreeCell - 7th level key
                     wins - Value name
                     REG_BINARY - Value type
                     46 0b 00 00 - Value data