POINTING STICK

The 'pointing stick' (trademarked by IBM as the 'TrackPoint') is an 'isometric joystick' used as a pointing device (compare especially touchpad). It was invented by research scientist Ted Selker. It 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, such as the UltraNav. Pointing stick devices are sometimes informally referred to as a "nipple" ^[1][2], "eraser head", "clit-mouse", or "nub" ^[3][4][5].
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 cap can also be a slightly rough "grippy cat's paw" material. The mouse buttons are usually operated by the right thumb, but some people use both left and right thumbs, for buttons 1/3 respectively.
The pointing stick operates by sensing applied force (hence it is also known as an isometric joystick), by using a pair of resistive strain gauges. The velocity of the cursor depends on the applied force.

Contents

Features

Problems

Comparison with Touchpads

Naming and Brands

References

External links

Features

The sensitivity of the TrackPoint is usually adjustable, and can be set to provide an extremely light touch. This is a matter of preference, however it is better to set the trackpoint sensitivity to be high than to use mouse-acceleration, since higher precision is then possible.
Press-to-select is an optional feature, where a sharp tap on the pointing stick is equivalent to a button-click. The button thus clicked can be configured to be 1, 2 or 3. However, it is quite easy to accidentally "click" the mouse when typing.
Together with software wheel-emulation, the Trackpoint (and 3 buttons) can provide almost the entire behaviour of a 3-button, 2-wheel mouse. Tapping button-2 will generate a middle-click; holding button-2 while simultaneously moving the pointer will generate vertical and horizontal scrolling events.
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.

Problems

Cursor drift is a ubiquitous problem among pointing sticks, requiring frequent recalibration. However, TrackPoints automatically recalibrate when the stick recognizes a steady cursor drift; to trigger a recalibration, the user must lift his finger temporarily off the TrackPoint for about 1 second.

Comparison with Touchpads

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. 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 easier 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 (although this can be partly solved by setting the sensitivity to high, and lifting the finger when the pointer is not being moved).

Naming and Brands

Name	Brand	Model
'TrackPoint'	IBM / Lenovo	ThinkPad, keyboards
'PointStick'	HP (Compaq)	NW9440, NW8440, NC8430, NC6400, NC4400, NC2400 & TC4400 Series
'NX Point'	NEC
'Stick Pointer'	Sony	BX
'StickPoint', 'QuickPoint'	Fujitsu	Lifebook E8310 (optional), E8410 (optional), S7110 (optional),
'Track Stick'	Dell	Latitude, Precision, Inspiron 4000, Inspiron 8200
'AccuPoint'	Toshiba	Portege (not current models 06/2007), Tecra A7, Tecra A8, Tecra M5, Tecra S Series
'FineTrack'	Acer	Travelmate 6492, Travelmate 6592

References

1. http://foldoc.org/?nipple
2. http://www.bitpipe.com/tlist/TrackPoints.html
3. http://catb.org/esr/jargon/html/N/nipple-mouse.html
4. http://listserv.linguistlist.org/cgi-bin/wa?A2=ind0006b&L=ads-l&P=7081
5. http://xkcd.com/c243.html

External links

★ IBM's TrackPoint page

★ How to configure the TrackPoint under Linux