Pen computing refers to any computer user-interface using a pen or stylus and tablet, over input devices such as a keyboard or a mouse.
Historically, pen computing (defined as a computer system employing a user-interface using a pointing device plus handwriting recognition as the primary means for interactive user input) predates the use of a mouse and graphical display by at least two decades, starting with the Stylator[1] and RAND Tablet[2] systems of the 1950s and early 1960s.