 Forth became very popular in the 1980s because it was well suited to the small microcomputers of that time , being compact and portable . At least one home computer , the British Jupiter ACE , had Forth in its ROM @-@ resident operating system . The Canon Cat also used Forth for its system programming , and Rockwell produced single @-@ chip microcomputers with resident Forth kernels , the <unk> and <unk> . A complete family tree is at TU @-@ Wien . <unk> <unk> was a version of Forth with graphics expansions for the Apple II . <unk> was a Forth expansion for measuring and controlling on PCs . 
