Trackballs

Just like its namesake in the Rodentia, the computer mouse needs room to roam and ends up almost anywhere. A mouse does not stay put because moving around is in its nature—and that's how you use it.

The problem is that many folks do not have room for a roaming rodent. Their desks are just too cluttered or they are traveling with a laptop and neglected to carry a desk along with them into the coach-class cabin. More insidious issues also involve mice. Pushing a plastic rodent requires clumsy, wasteful, and tiring whole-arm movements. Mice are inefficient and exhausting.

The leading mouse alternative, the trackball, eliminates these problems. Essentially a mouse turned upside down, the trackball is much like it sounds—an often big ball that, when rotated, causes the screen pointer (mouse cursor) to track its movements. The trackball spins in place and requires no more desk space than its base, a few square inches.

Switches

As with mice, trackballs also require switches so that you can indicate when the cursor is pointing to what you want. Most trackballs have two or three pushbuttons that duplicate the selection functions of mouse buttons. Although some trackballs boast four buttons, the foursome typically functions as two duplicate pairs—mirror images—so that one trackball can serve either a right or left hand.

No standard exists for switch placement on trackballs because no consensus exists on how you are supposed to operate a trackball. Some are designed so that you spin the ball with your fingers. Others prefer that your thumb do the job. Which is better depends on whom you believe and how you prefer to work.

According to one theory, your fingers are more agile than your thumb and therefore more precise at spinning the ball, so you should get a trackball that you operate with your fingers. A competing theory holds that the thumb has more muscle control than the fingers, so a thumb-operated trackball makes more sense. Some trackball-makers wisely avoid such issues and make trackballs that can be used equally adeptly by the posed or opposed digit. In truth, which design and how you use a trackball is a matter of preference rather than hard science.

Ball Size

Another trackball design choice is the size of the ball itself and how it is retained inside the mechanism. Various products range in dimensions from the size of a shooter marble to those equaling cue balls. Bigger once was thought to be better, but the trackballs built into laptop and notebook computers are making smaller sizes popular.

Because no definitive study has shown the superiority of any particular size for a trackball, the best advice is to select one that feels best to you—or the one that comes already attached to your computer.

As with the balls in mechanical mice, trackballs naturally attract dirt. Although the trackball doesn't pick up dirt from rolling around, dust does fall upon the ball and the oils from your fingers collect there, too. A readily removable ball can be quickly and easily cleaned. This sort of serviceability is absent from many trackball designs—something to consider if you plan on using your trackball for a long time.

Optical trackballs are growing in popularity. Most work like old-fashioned optical mice, only the pattern used for recognition is part of the ball itself. If you look closely at the big red ball that these optical trackballs use, you can see the faint lines that sensors inside the trackball mechanism detect. Optical trackballs require less maintenance than the mechanical kind, although if they get really dirty you'll need to swab off their optical sensors, which are readily visible once you remove the ball. Use a Q-tip dampened with plain water. Resort to window cleaner only if using water alone is not successful.

Handedness

Most mice are symmetrical. Although two- and three-button mice define different functions for their left- and right-side buttons, most enable you to flip the functions of the buttons to suit right- or left-hand operation if what button falls under a given finger is important to you.

Trackballs, however, are sometimes asymmetrical. In itself, that can be good. An asymmetrical trackball can better fit the hand that it is designed for, right or left. But this handedness among trackballs poses a problem when you make your purchase—you have to determine whether you want a right- or left-handed trackball. Which you need does not necessarily correspond to the way you write. Some left-handed people prefer right-handed trackballs (and some righties like lefties). Consequently, a right-handed trackball isn't always the best choice for a right-handed person. Before you buy a one-handed trackball, make sure you know which hand you will favor in using it. If you switch hands when you tire from using one hand for spinning your trackball all day long, you may not want a product with definite handedness at all.

Resolution

Somewhere buried in the specification of a trackball, you may find a resolution rating, either as the number of counts per inch (CPI) of movement or as DPI (as with mice). These figures are rarely published anymore because today's driver software makes them irrelevant. Trackball resolution indicates how much you have to spin a ball to move the cursor on the screen—higher resolution requires more spin to move the cursor. Software drivers allow trackball manufacturers to give you several choices for the effective resolution of their products so that you can tailor their actions and reactions to match the way you work. In addition, most trackball-makers offer ballistic operation in which the translation of ball movement to onscreen cursor change varies with the speed of the ball's spin. This yields fast positioning without loss of precision. The only problem is getting used to such nonlinear control in which the speed at which you spin the trackball has as much (and sometimes more) effect as how far you spin it.

Unlike most other peripherals, no one trackball is objectively better than the rest. Operating any of them is an acquired talent like brain surgery, piano-playing, or hair-combing. Any judgment must be subjective, and which is better suited a particular user depends most on personal preference and familiarity.