Trackball

[1] Users roll the ball to position the on-screen pointer, using their thumb, fingers, or the palm of the hand, while using the fingertips to press the buttons.

Some trackballs have notably low friction, as well as being made of a dense material such as phenolic resin, so they can be spun to make them coast.

[citation needed] Before the advent of the touchpad, small trackballs were common on portable computers (such as the BlackBerry Tour) where there may be no desk space on which to run a mouse.

[3][4] Benjamin's project used analog computers to calculate the future position of target aircraft based on several initial input points provided by a user with a joystick.

Principal designers Tom Cranston, Fred Longstaff and Kenyon Taylor chose the trackball as the primary input, using a standard five-pin bowling ball as the roller.

DATAR was similar in concept to Benjamin's display, but used a digital computer to calculate tracks, and sent the resulting data to other ships in a task force using pulse-code modulation radio signals.

Since 1966, the American company Orbit Instrument Corporation produced a device named X-Y Ball Tracker, a trackball, which was embedded into radar flight control desks.

In order to provide smooth motion the balls were often covered with an anti-slip surface treatment, which was, by design, sticky.

Rolling the mouse tended to pick up any dirt and drag it into the system where it would clog the chopper wheels, demanding cleanup.

In the late 1990s both mice and trackballs began using direct optical tracking which follows dots on the ball, avoiding the need for anti-slip surface treatment.

Large trackballs are sometimes seen on computerized special-purpose workstations, such as the radar consoles in an air-traffic control room or sonar equipment on a ship or submarine.

Large and well made ones allow easier high precision work, for which reason they may still be used in these applications (where they are often called "tracker balls") and in computer-aided design.

This combination provides for two-hand aiming and a high accuracy and consistency replacement for the traditional mouse and keyboard combo generally used on first-person shooter games.

Many such games natively support joysticks and analog player movement, like Valve's Half-Life and id Software's Quake series.

Because trackballs for personal computers are stationary, they may require less space for operation than a mouse, simplifying use in confined or cluttered areas such as a small desk or a rack-mounted terminal.

Application users are encouraged to test different devices, and to maintain proper posture and scheduled breaks for comfort.

These miniature trackballs are made to fit within the thickness of a mobile device, and are controlled by the tip of a finger or thumb.