Abstract :
Since 1980, technology has reduced the size and the weight of personal computers; without substantially changing the way users interact with their computing environment. Conventional input/output devices place an ultimate limit on the size and the weight of personal computers. Size is limited by the conventional typewriter-like keyboard whose dimensions have not really changed this past hundred years. Both size and weight are limited by displays the size of notebook paper intended to be viewed from several feet away. Since the size of the display places a lower bound on the personal computer´s energy consumption, weight is dictated primarily by the weight of the energy storage devices, such as batteries.<>
