PC Hardware A Beginner’s Guide

(^472) PC Hardware: A Beginner’s Guide
Trackballs
A trackball is essentially an upside-down mouse. As shown in Figure 18-26, a trackball is
a mouse-like tool that has two or more buttons and a ball on to pof the device. The ball,
which can be located on the to por side of the trackball, is mani pulated with either a
thumb or finger to move the cursor on the screen. A trackball, which can be either a
corded or cordless device (the one in Figure 18-26 is a cordless unit), uses essentially the
same technology as an optomechanical mouse to communicate its movements to the PC
and connects through the PS/2 and USB connections.
Inatrackball,therubber-coatedballusedinamouseisreplacedwithasmoothballthatis
about the size of a golf ball. When the trackball is moved, two rollers that touch the trackball
are rotated and ultimately movement data is sent to the PC. Only the ball on a trackball pointing
device moves, which means a trackball requires less space on the desktop.
Glidepoint Mouse
Glidepoint mice are predominantly found on notebook PCs, but there are a few key-
boards available that include this type of pointing device. A glidepoint mouse, shown in
Figure 18-27, is the pivoting rubber-tipped device that looks like an eraser tip and is
located between the G and the H keys on a notebook PC keyboard. A glidepoint mouse
works like a very small joystick (see below), but acts like a mouse on the screen.
Glidepoint technology allows the user to leave their hands on the keyboard, assuming
they are using the notebook’s internal keyboard.
Figure 18-26. A trackball pointing device. Photo courtesy of Logitech, Inc.