The Registry has become the central repository for all the configuration information in the Microsoft 32 bit operating systems. Both Windows NT and Windows 95 store configuration information for hardware and software components in the registry.
The Windows 95 registry supports both static data and dynamic data. A static value is one that is actually stored within the registry on disk. Dynamic data is data that changes very often, such as performance data. It is not practical to store such data in the registry; it would obviously not be a good idea for the system to continually update the registry with current values. Thus, a different mechanism was designed to support dynamic data.
Note
Windows NT 3.5 supports dynamic data differently than Windows 95. Windows NT 3.5 uses Volatile keys, which Windows 95 does not support.
Dynamic keys were introduced in Windows 95 to handle dynamic registry data. Rather than storing the actual values, the registry stores a pointer to a function that returns a value or values. When a registry call is made to query a value or values associated with a dynamic key, that function is called to return the desired value(s). From the point of view of the consumer of registry data (the caller of the registry API's), dynamic keys appear and behave like any other keys in registry name space (except that they are read-only).