A mouse is a small
device that a computer user pushes
across a desk surface in order to
point to a place on a display screen
and to select one or more actions to
take from that position.
The mouse first became a widely-used
computer tool when Apple Computer
made it a standard part of the Apple
Macintosh.
Today, the mouse is an integral part
of the graphical user interface
(GUI) of any personal computer. The
mouse apparently got its name by
being about the same size and color
as a toy mouse.
A mouse consists of a metal or
plastic housing or casing, a ball
that sticks out of the bottom of the
casing and is rolled on a flat
surface, one or more buttons on the
top of the casing, and a cable that
connects the mouse to the computer.
As the ball is moved over the
surface in any direction, a sensor
sends impulses to the computer that
causes a mouse-responsive program to
reposition a visible indicator
(called a cursor) on the display
screen. The positioning is relative
to some variable starting place.
Viewing the cursor's present
position, the user readjusts the
position by moving the mouse.
The most conventional kind of mouse
has two buttons on top: the left one
is used most frequently. In the
Windows operating systems, it lets
the user click once to send a
"Select" indication that provides
the user with feedback that a
particular position has been
selected for further action.
The next click on a selected
position or two quick clicks on it
causes a particular action to take
place on the selected object.
For example, in Windows operating
systems, it causes a program
associated with that object to be
started. The second button, on the
right, usually provides some
less-frequently needed capability.
For example, when viewing a Web
page, you can click on an image to
get a popup menu that, among other
things, lets you save the image on
your hard disk. Some mouses have a
third button for additional
capabilities. Some mouse
manufacturers also provide a version
for left-handed people.
Windows 95 and other operating
systems let the user adjust the
sensitivity of the mouse, including
how fast it moves across the screen,
and the amount of time that must
elapse within a "double click.". In
some systems, the user can also
choose among several different
cursor appearances. Some people use
a mousepad to improve traction for
the mouse ball.
Although the mouse has become a
familiar part of the personal
computer, its design continues to
evolve and there continue to be
other approaches to pointing or
positioning on a display.
Notebook computers include built-in
mouse devices that let you control
the cursor by rolling your finger
over a built-in trackball. IBM's
ScrollPoint mouse adds a small
"stick" between two mouse buttons
that lets you scroll a Web page or
other content up or down and right
or left. Users of graphic design and
CAD applications can use a stylus
and a specially-sensitive pad to
draw as well as move the cursor.
Other display screen-positioning
ideas include a video camera that
tracks the user's eye movement and
places the cursor accordingly.
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