Although the Registry replaces the basic function of the initialization files used in earlier versions of Windows, the SYSTEM.INI, WIN.INI, and WINFILE.INI files still appear in the Windows directory. These files continue to be used for compatibility with earlier Windows-based applications and device drivers. For example, entries in WIN.INI and SYSTEM.INI created by Win16-based applications are not updated in the Registry, because such applications do not know how to access the Windows 95 Registry.
If you install Windows 95 as an upgrade over Windows 3.1, some INI file settings are copied into the Registry, including settings from CONTROL.INI, PROGMAN.INI, SYSTEM.INI, and WIN.INI.
Some INI file entries are not moved to the Registry, but remain in the INI file for compatibility with Win16-based applications. Most of these entries can be changed without editing the INI files by using the graphical tools provided with Windows 95. However, some INI entries cannot be set using the Windows 95 user interface. These entries are required for some applications to function properly, but shouldn't need direct modification by users.