The Free Software Foundation ( FSF ) is a non-profit corporation founded by Richard Stallman on 4 October 1985 to support the free software movement , a copyleft-based movement which tries to promote the universal freedom to distribute and modify computer software without restriction . The Free Software Foundation ( FSF ) is a non-profit corporation founded by Richard Stallman on 4 October 1985 to support the free software movement , a copyleft-based movement which aims to promote the universal freedom to create , distribute and modify computer software .