A keyboard is the most common input device, found on virtually all computers, and is modeled after the QWERTY input interface layout of a typewriter. It is comprised of a panel of keys which represent a variety of characters and functions. Some keyboards are integrated in the computer system, such as in most |laptops|, |notebooks|, and |palmtops|. Others are separate units and are connected to the system through input ports, as in |desktops| and |towers|. Keyboards come in a variety of designs, from the compact palmtop, laptop, and notebook designs to the extended and enhanced designs of the more recent desktop and tower systems.
