Editing Windows 9x (section)

===Registry===
Like Windows NT, Windows 9x stores user-specific and configuration-specific settings in a large information database called the [[Windows registry]]. Hardware-specific settings are also stored in the registry, and many device drivers use the registry to load configuration data. Previous versions of Windows used files such as <code>[[AUTOEXEC.BAT]]</code>, <code>[[CONFIG.SYS]]</code>, <code>[[WIN.INI]]</code>, <code>[[SYSTEM.INI]]</code> and other files with an <code>.INI</code> extension to maintain configuration settings. As Windows became more complex and incorporated more features, <code>.INI</code> files became too unwieldy for the limitations of the then-current FAT filesystem. Backwards-compatibility with <code>.INI</code> files was maintained until Windows XP succeeded the 9x and NT lines.

Although Microsoft discourages using .INI files in favor of Registry entries, a large number of applications (particularly 16-bit Windows-based applications) still use .INI files. Windows 9x supports .INI files solely for compatibility with those applications and related tools (such as setup programs). The AUTOEXEC.BAT and CONFIG.SYS files also still exist for compatibility with real-mode system components and to allow users to change certain default system settings such as the PATH environment variable.

The registry consists of two files: User.dat and System.dat. In Windows Me, Classes.dat was added.