The system registry is a hierarchical database that stores values for applications on the system. The hierarchy’s root is named MyComputer and is divided into the several subtrees that are also called hives. Which hives are available depends on your operating system. The following table summarizes the most commonly available hives. (The “HKEY” part of each name stands for “hive key.”)

HKEY_CLASSES_ROOT Definitions of types or classes, and properties associated with those types.
HKEY_CURRENT_CONFIG Information about the system’s current hardware configuration.
HKEY_CURRENT_USER The current user’s preferences (such as environment variable settings, program group information, desktop settings, colors, printers, network connections, and preferences specific to applications). Each user has separate HKEY_CURRENT_USER values. This is usually the subtree where a Visual Basic application stores and retrieves its settings.
HKEY_DYN_DATA Performance data for Windows 95, 98, and Me. (Yes, this is a bit outdated but this hive is still there.)
HKEY_LOCAL_MACHINE Information about the computer’s physical state including bus type, system memory, installed hardware and software, and network logon and security information.
HKEY_USERS Default configuration information for new users and the current user’s configuration.

Depending on your operating system, the registry may also contain the unsupported keys HKEY_PERFORMANCE_DATA, HKEY_PERFORMANCE_NLSTEXT, ...

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