Pen computing: some human factors issues

Pen based computing is already a practical possibility, and for some products that have now reached the market, the pen is the sole medium for user input. These devices, sometimes described as personal digital assistants (PDA) are designed to be hand held, and utilise both handwriting recognition and storage of digital ink. Elsewhere, keyboard and pen may be combined in systems designed for office use. Within a graphical user interface, the pen can be used for pointing and selection functions, as well as text entry and drawing. The ability to enter text directly onto any location on the display screen makes pen input particularly appropriate for tasks that have a form-filling structure, and highlights the `pen and paper´ metaphor associated with pen computing. As progress in handwriting recognition increases the versatility of pen interfaces, this metaphor appears more and more sustainable. In principle, any type of pen and paper activity could soon be reproduced in these systems