Working Knowledge; July 1998; Scientific American Magazine; by Gerpheide; 1 Page(s)

The most common pointing device on new laptop computers is the touchpad, a small black or gray rectangle typically located below the keyboard. Moving a finger across the pad causes the cursor to move similarly on the screen.

Touchpads began appearing on laptops only about four years ago, but they have already displaced built-in trackballs as the standard pointing device on portable computers. Today more than two thirds of all laptops sold come equipped with touchpads. (The remainder, mostly IBM and Toshiba models, use the small, red joysticklike pointer, which resembles a pencil eraser and is located between the "G," "H" and "B" keys on the keyboard.) Touchpads offer better ergonomics for many people, such as those afflicted with arthritis. And because the devices are completely sealed and have no moving parts, dirt or grit cannot get inside them, making them more suited to dusty or corrosive environments, such as workshops, factory floors and garages.