(SYStem INItialization) An early Windows 3.x configuration file that described the current computer system environment. Introduced in Windows 3.0, SYSTEM.INI was read when Windows was loaded to obtain information about the drivers, memory management and other hardware details. It is also read in subsequent Windows versions for compatibility. When a user or application changed settings, Windows updated SYSTEM.INI; however, the file could also be edited with any text editor just like WIN.INI, another major configuration file in early Windows. See WIN.INI, INI file and Registry.