Microsoft Office Tutorials and References
In Depth Information
Input and Output
Input and Output
The data or instructions you type into the computer are called input . The result of the
computer processing your input is referred to as output . The computer takes care of the
processing function; you need additional components, called peripheral devices , to
accomplish the input and output functions.
You use an input device , such as a keyboard or a mouse, to input data and issue
commands. The computer can also receive input from a storage device. The top keyboard in
Figure 15 is a standard keyboard. The bottom keyboard in Figure 15 is ergonomic , which
means that it has been designed to ﬁ t the natural placement of your hands and should
reduce the risk of repetitive motion injuries. Many keyboards, like the ones shown, have
additional keys programmed as shortcut keys to commonly used functions.
Another way to help
avoid repetitive motion
injuries is to take frequent
breaks when working at a
computer and stretch your
hands and wrists.
Personal computers are equipped with a pointing device. A pointing device controls
the pointer , a small arrow or other symbol on the display screen. Pointing devices are
used to select commands and manipulate text or graphics on the screen. A mouse is
shown on the left in Figure 16. An ordinary mouse has a rolling ball on its underside,
and an optical mouse has a tiny camera on its underside that takes pictures as the mouse
is moved. A mouse usually has two or more buttons for clicking commands. You control
the pointer by moving the entire mouse around on your desk. A mouse might also have a
scroll wheel that you roll to scroll the page on the screen and that might function as one
of the buttons. The trackball , such as the one shown on the right in Figure 16, is similar
to a mouse except that the rolling ball is on the top side and you control the movement
of the pointer by moving only the ball.