Although the keyboard and the mouse are the input devices that people
use most often, there are many other ways to input data into a computer
. Sometimes the tool is simply a matter of choice.
Some users just prefer the feel of a trackball over a mouse.
In many cases, however, an
ordinary input device may not be the best choice. In a dusty factory or
warehouse, for example,
- a standard keyboard or mouse can be damaged if it becomes clogged with dirt.
- Grocery checkout lines would slow down dramatically if cashiers had to manually input product codes and
In these environments, specialized input devices tolerate extreme
conditions and reduce the risk of input errors. Alternative input devices are important parts of some special purpose computers.
Tapping a handheld computer's screen with a pen is a much faster way to input commands than typing on a miniature keyboard.
On the other hand, a specialized device can give new purpose to
a standard system. If you want to play action-packed games on your
home PC, for example, you will have more fun if you use a joystick or
game controller than a standard keyboard
This chapter examines several categories of alternative input devices
and discusses the special uses of each. You may be surprised at how often you see these devices, and you may decide that an alternative device will be your primary means of interacting with your computer