Hardware Reference
In-Depth Information
features on your desktop keyboard. For desktop systems, I use a Lenovo keyboard with the TrackPoint
built in. This makes for a more consistent interface between desktop and laptop systems because I can
use the same pointing device in both environments.
Touch Pads
The first touch pad was included on the ill-fated Gavilan portable computer in 1982; however, it
didn't catch on until many years later. Cirque originated the modern touch pad (also called a
track
pad
) pointing device in 1994. Cirque refers to its technology as the GlidePoint and has licensed the
technology to other vendors such as Alps Electric, which also uses the term GlidePoint for its touch
pads. The GlidePoint uses a flat, square pad that senses finger position through body capacitance.
This is similar to the capacitance-sensitive elevator button controls you sometimes encounter in office
buildings or hotels.
When it is used on a portable computer's keyboard, the touch pad is mounted below the spacebar, and
it detects pressure applied by your thumbs or fingers. Transducers under the pad convert finger
movement into pointer movement. Several laptop manufacturers have licensed this technology from
Cirque and have incorporated it into their portable systems. Touch pads are also integrated into a
number of mid-range to high-end keyboards from many vendors. When used on a desktop keyboard,
touch pads are often offset to the right side of the keyboard's typing area.
Touch pads feature mouse buttons, although the user also can tap or double-tap on the touch pad's
surface to activate an onscreen button located under the touch pad's cursor. Dragging and dropping is
accomplished without touching the touch pad's buttons; just move the cursor to the object to be
dragged, press down on the pad, hold while moving the cursor to the drop point, and raise the finger
to drop the object. Some recent models also feature additional hot buttons with functions similar to
those on hot-button keyboards, as well as a vertical scrollbar on the side and the capability to tap the
touch pad to simulate a mouse click.
The primary use for touch pads has been for laptop computer- and desktop keyboard-integrated
pointing devices, although Cirque and Alps have both sold standalone versions of the touch pad for
use as a mouse alternative on desktop systems. Cirque's touch pads can be purchased direct from the
Cirque website. The Smart Cat Pro Touchpad has enhanced software to support touch gestures, has
programmable hot buttons, and includes other features to make web surfing easier.
Although it has gained wide acceptance, especially on portable computers, touch pad technology can
have many drawbacks for some users. Operation of the device can be erratic, depending on skin
resistance and moisture content. The biggest drawback is that to operate the touch pad, users must
remove their hands from the home row on the keyboard, which dramatically slows their progress. In
addition, the operation of the touch pad can be imprecise, depending on how pointy your finger or
thumb is! On the other hand, if you're not a touch typist, removing your hands from the keyboard to
operate the touch pad might be easier than using a TrackPoint. Even with their drawbacks, touch pad
pointing devices are vastly preferable to using a trackball or a cumbersome external mouse with
portable systems.
Unless you want to use a “real” mouse with a portable system, I recommend you sit down with
portable computers that have both touch pad and TrackPoint pointing devices. Try them yourself for
typing, file management, and simple graphics and see which type of integrated pointing device you
prefer. I know what I like, but you might have different tastes.
Trackballs
