In the Microsoft Windows operating systems beginning with Windows 95, the registry is a single place for keeping such information as what hardware is attached, what system options have been selected, how computer memory is set up, and what application programs are to be present when the operating system is started. The registry is somewhat similar to and a replacement for the simpler INI (initialization) and configuration files used in earlier Windows (DOS-based) systems. INI files are still supported, however, for compatibility with the 16-bit applications written for earlier systems.
In general, the user updates the registry indirectly using Control Panel tools, such as TweakUI. When you install or uninstall application programs, they also update the registry. In a network environment, registry information can be kept on a server so that system policies for individuals and workgroups can be managed centrally.