| When less is more and more is bore.... | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| |||||||||
| With normal reading speed averaging 230 wpm, 3 MINUTES is the most that you will ever need to read any Dummipedia article. | |||||||||
| |||||||||
Trackball 
A trackball is a pointing device consisting of a ball, housed in a socket containing sensors to detect rotation of the ball about two axes. It is like an upside-down mouse with an exposed protruding ball. Before the advent of the touchpad, small trackballs were common on portable computers, where there may be no desk space on which to run a mouse. Large tracker balls are common on CAD workstations for easy precision.
| |
2. Trackballs are generally either:
- symmetrical in design, with the ball operated by the fingers; or
- asymmetrical, with the ball operated by the thumb to move a cursor.
Many users favour one format or another, for reasons of comfort, precision, or because it reduces strain on one part of the hand/wrist. Only the symmetric format can be used by both hands. Asymmetric or "handed" trackballs are not generally available in left-handed configurations, due to small demand.
| |
3. When mice and trackballs still had chopper wheels, trackballs had the advantage of being in contact with the user's hand, which is generally cleaner than the desk or mousepad and doesn't drag lint into the chopper wheels. The late 1990s advent of scroll wheels, and the replacement of mouseballs by direct optical tracking, put trackballs at a disadvantage and forced them to retreat into niches where their distinctive merits remained important. Most trackballs now have direct optical tracking which follows dots on the ball. Some mice, in place of a scroll wheel, acquired a small trackball between the buttons, useful in maps and other circumstances calling for scrolling in two dimensions.
| |
4. Trackballs have appeared in computer and video games, particularly early arcade games. Football, released by Atari in 1978, was the first arcade game to use a trackball. Console trackballs, once common in the early 1980s, are now fairly uncommon. Computer gamers have been able to successfully use trackballs in most modern computer games, with any slight loss of speed compensated for with an increase in precision. However, many gamers are deterred by the time it takes to 'get used to' the different style of hand control that a trackball requires.
| |
5. Some computer users prefer a trackball over the more common mouse for ergonomic reasons. At times when a user is browsing menus or websites rather than typing, it is also possible to hold a trackball in the right hand like a television remote control, operating the ball with the right thumb and pressing the buttons with the left thumb, thus giving the fingers a rest. However, there does not seem to be conclusive evidence of one being better than the other in terms of comfort.
| |
6. Some disabled users find trackballs easier since they only have to move their thumb relative to their hand, instead of moving the whole hand, while others incur unacceptable fatigue of the thumb. Elderly people sometimes have difficulty holding a mouse still while double-clicking; the trackball allows them to let go of the cursor while using the button. more... at Wikipedia
| |
