A keyboard is the most common input device, found on virtually all computers. Modeled after the QWERTY layout of a typewriter, it is comprised of a panel of keys which represent letters, numbers, and special keys. Keyboards are usually separate units, connected to the system with a |cable|, as in |desktop| and |tower| systems. Some keyboards are integrated into the system, as in most |laptops|, |notebooks|, and |palmtops|. 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.
