The first version of Mac OS (simply called System) is easily distinguished between many other operating systems from the same period because it does not use a command line interface; it was one of the first operating systems to use an entirely graphical user interface or GUI. Additional to the system kernel is the Finder, an application used for file management, which also displays the Desktop. The two files were contained in a folder directory labeled System Folder, which contained other resource files, like a printer driver, needed to interact with the System.