The Windows Registry database stores the configuration options and settings for the Windows operating system and software installed on your computer.
The Registry is organized in a hierarchical structure containing keys and values, with five different 'root' keys at the top, as shown below, that serve a particular purpose.
The five different root keys in the Windows registry and their purposes are:
HKEY_CLASSES_ROOT (HKCR): This key stores information about file associations and OLE object classes.
HKEY_CURRENT_USER (HKCU): This key stores information about the current user's settings and a specific user's preferences for various applications.
HKEY_LOCAL_MACHINE (HKLM): This key stores information that affects the entire computer, regardless of the logged-in user. These settings are for the computer's hardware, operating system configuration, and software settings that affect all users.
HKEY_USERS (HKU): This key stores information about all users who have logged on to the computer.
HKEY_CURRENT_CONFIG (HKCC): This key stores information about the current hardware configuration of the computer.
For the most part, you will be modifying keys and values under the HKCU and HKLM root keys.
Registry keys are like folders containing other keys and values used to organize and group related settings.
For example, the HKEY_CURRENT_USER key contains settings for the current user account, such as a user's desktop wallpaper, installed application preferences, and personal settings.
While keys are like folders, Registry values are the files stored within them, containing the specific settings for a particular key. They can have different data types, including text, numbers, and binary data.
There are several different types of registry value data types:
- REG_SZ - A string value that contains text data, such as a username or folder path.
- REG_DWORD - A numeric value that contains a 32-bit integer.
- REG_QWORD - A numeric value that contains a 64-bit integer.
- REG_BINARY - A value that contains binary data, such as an image or sound file.
- REG_MULTI_SZ - A string value that contains multiple strings separated by null characters. This is often used for lists or arrays of values.
Each registry value type is used for a specific purpose, and understanding them can help you better manage and customize your Windows operating system.
