1986 - Berkeley Softworks released GEOS (“Graphic Environment Operating System”) for the Commodore 64. (Yes, that C64 - the Guinness World Record holder for the highest-selling computer of all time.) One rather interesting bit: the file manager didn't use scrollbars. Instead, it used a page turning metaphor when multiple pages worth of file icons needed to be displayed. GEOS became so popular that Commodore began bundling it, by default, with some versions of the C64 computer and, for a spell, GEOS was the third-most popular operating system in the world – behind only MS-DOS and MacOS.