As we said before, the registry stores a great amount of information, including profiles of all users, information on installed applications and types of documents that can be created by each program, information on folder properties and application shortcuts, installed hardware and ports that are used.

Because the Windows registry is a complex relational database, all information that can be stored in the resulting information containers of this database (values), must be strictly classified. Values are classified by a data type, which represents the specific kind of data that the value can store. Overall, there are 11 types of data.

As we said before, the registry is a hierarchical database where information is presented on a number of levels (up to 6). Hive keys are on the first level.

The Microsoft Computer Dictionary defines the registry as a central hierarchical database used in the Microsoft operating systems starting with Microsoft Windows 98. The database stores information that is necessary to configure the system for users, applications and hardware devices.