Pointing stick
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- This article is about the computer pointing device. For other meanings, see Pointing stick (disambiguation).
The pointing stick (trademarked by IBM as the TrackPoint) is a pointing device (compare especially Touchpad) for laptops invented by research scientist Ted Selker and is present on many brands of laptop, including IBM's line of ThinkPad laptops (now made by Lenovo) and on Dell Latitudes under the name of Track Stick. It has also been observed on computer mice and on some desktop keyboards.
The pointing stick has a replaceable rubber cap, traditionally red on the ThinkPad but also found in other colors on other machines. On a QWERTY keyboard, the stick is embedded between the 'G', 'H' and 'B' keys, and the mouse buttons are placed just below the Spacebar.
The pointing stick operates by sensing applied force (hence it is also known as an isometric joystick), typically by measuring the resistance of a material. The velocity of the cursor depends on the applied force.
The Trackpoint III and the Trackpoint IV have a feature called Negative Inertia that causes the cursor's velocity to "overreact" when it is accelerated or decelerated. Usability tests at IBM have shown that it is easier for users to position the cursor with Negative Inertia enabled than it is with the feature disabled.
Cursor drift is a ubiquitous problem among pointing sticks, requiring frequent recalibration. However, TrackPoints automatically recalibrate when the stick recognizes a steady cursor drift.
The pointing stick seems to be declining in deployment, to the dismay of those who find it to be preferable to either mouse or touchpad [citation needed]. It is especially liked by touch-typists because it is one of the few pointing devices which does not require the user to remove their fingers from the home row. Unlike a touchpad, a pointing stick allows a user to move the cursor large distances without the need to pause to reposition their finger. Some people find it easer to finely position the pointer than when using a touchpad because there is virtually no 'dead zone'. One criticism is that because the pointing stick depends on the user applying pressure, it can cause hand cramps.
Pointing stick devices are sometimes referred to as a "nub", "eraser", or "nipple".
