Pointing stick

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A ThinkPad laptop featuring both a red pointing stick (top left) and a touchpad (center)
IBM Thinkpad caps: Soft Rim, Classic Dome, Soft Dome

The pointing stick (trademarked by IBM as the TrackPoint & by Synaptics as the Touchstyk) is an isometric joystick used as a pointing device (compare especially touchpad and trackball). 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), Toshiba Satellite laptops, HP business notebooks and on Dell Latitudes under the name of Track Stick. It has also been observed on computer mice and on some desktop keyboards (as an integrated pointing device).

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. 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 mouse buttons can be operated right-handed or left-handed due to their placement below the keyboard along the centerline.

The pointing stick has a replaceable rubber cap, traditionally red on the ThinkPad but also found in other colors on other machines. The cap can be a slightly rough "eraser head" material (Classic Dome) or other optional shapes (Soft Dome or Soft Rim).[1]


[edit] Features

The sensitivity of the TrackPoint is usually adjustable, and can be set to provide an extremely light touch.

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 behavior 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. Negative Inertia is intended to avoid feeling of inertia or sluggishness when starting or stopping movement[2]. Usability tests at IBM have shown that it is easier for users to position the cursor with Negative Inertia, and performance is 7.8% better [3].

[edit] 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 or her finger temporarily off the TrackPoint for about 1 second.

[edit] History

The concept of TrackPoint was created in 1984 by Ted Selker, a PARC researcher. He learned about a study that demonstrated that it takes relatively long time, three-quarters of a second, for a computer user to shift his hand from the keyboard to the mouse, and as much time to shift back. Ted Selker wanted to construct a device that would largely eliminate this delay. Selker built a model of a pointing stick, but actually had no time to work on it. Three years later, working at IBM, Selker was able to refine the TrackPoint design and transform his invention into a product.[4].

[edit] Comparison with touchpads

The pointing stick can be used in ultra-compact netbooks (see Sony Vaio P, for example[5]) where there would be no place for a touchpad.

The pointing stick is especially liked by touch-typists and IT professionals because it is one of the few pointing devices which does not require the user to remove their fingers from the home row. The device has a very loyal user base, with users who refuse to buy a laptop unequipped with the device. Some users even choose to wear a TrackPoint cap as a badge to show their support[6].

[edit] Subjective claims

Some people find it easier to finely position the pointer than when using a touchpad because there is virtually no 'dead zone'. Some users feel that pointing stick causes less wrist strain, because user does not need to avoid resting wrists on a touchpad, usually located just below the keyboard. Some people find them more appealing for mobile gaming than a touchpad, because the track-point allows infinite movement without repositioning. [7].

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). Another criticism is that it stresses the index finger and may lead to RSI injuries. In addition, a finger slipping off of the stick can lead to accidental pressing of one or more keys in immediate proximity.

[edit] Objective studies comparing pointing stick and touchpad performance

A number of ergonomic studies to compare trackpoint and touchpad performance have been done [8][9][10]. Most studies find that touchpad is slightly faster; one study found that "the touchpad was operated 15% faster than the trackpoint"[10]. Another study found that average object selection time was faster with a touchpad, 1.7 sec compared to 2.2 sec with a trackpoint, and object manipulation took 6.2 sec with a touchpad, on average, against 8.1 sec with trackpoint[11].

It should be noted that these studies measured pointing performance only and cannot verify or disprove the claim that trackpoint is faster in a mix of pointing and typing actions.

[edit] Naming and brands

Name Brand Current Models Past Models
TrackPoint IBM / Lenovo All known ThinkPads (not IdeaPads), and Travel Keyboard with Ultranav Most ThinkPads, Space Saver II, Model M13, Model M4-1, Trackpoint IV, Trackpoint USB Keyboard
PointStick HP (Compaq) 2510p, 2530p, 2710p, 2730p, 6910p, 6930p, 8510p/w, 8710p/w, 8530p/w, 8730w nc2400, nc4400, nc6230, nc6400, nc8430, nw8440, nw9440, & tc4400 series
NX Point NEC EasyNote MX45, MX65, S5
Pointing Stick Sony Sony Vaio P netbook BX series, U8 series, UX series
StickPoint, QuickPoint Fujitsu P1620, T2010, optional on E8410, S7210, E8310, U2010 S7110 (optional), B2400/2500/2600 series, P1120, P1510, P1610, U1010/U810/U50
Track Stick Dell Latitude D430, D630, D830, XT, E4300, E5400, E6400, E6400 ATG, E6500, Precision M2300, M2400, M4300, M4400, M6400 Latitude; Precision; Inspiron 4000, 8100, 8200, 9100
AccuPoint Toshiba Tecra A9, A10, M9, M10 Portege (not current models 06/2007), Tecra A7, Tecra A8, Tecra M2, Tecra M5, Tecra S Series, Satellite Pro 4000 Series, Satellite Pro 410 Series
FineTrack Acer Travelmate 6492, Travelmate 6592
Mouse emulator Elonex Elonex ONE
Pointing Stick Unicomp EnduraPro, Mighty Mouse (both for desktops) On-The-Stick

Slang names

Pointing stick devices are sometimes informally referred to as a "nipple" mouse[12][13], "clit mouse"[14][15], or "nub"[15].

[edit] References

  1. ^ "Lenovo Support and Downloads: TrackPoint Caps and how to order for ThinkPad systems and TrackPoint Keyboards". IBM.com. 2007-07-17. http://www-307.ibm.com/pc/support/site.wss/VLAR-443LTU.html. Retrieved on 2009-04-06. 
  2. ^ US Pat. 5570111 - International Business Machines Corporation, GUI cursor positioning device having a negative inertia transfer function
  3. ^ Negative Inertia: A Dynamic Pointing Function. R. C. Barrett, E. J. Selker, J. D. Rutledge*, R. S. Olyha* IBM Almaden Research Center
  4. ^ http://www.petergolden.com/Articles/ThinkPad-1(EB-PAG).htm Peter Golden, big BLUE'S big ADVENTURE
  5. ^ Engadget: Sony Vaio P hands-on
  6. ^ http://lenovoblogs.com/designmatters/?p=119 Lenovo blogs: Design Matters. TrackPoint Loyalists: Show Your Colors
  7. ^ Trackpoint vs Touchpad discussion
  8. ^ Batra, S., Dykstra, D., Hsu, P., Radle, K. and Wiedenbeck, S., 1998, Pointing device performance for laptop computers. Proceedings of the Human Factors and Ergonomics Society 42nd Annual Meeting (pp. 535-540). Santa Monica, CA: Human Factors Society.
  9. ^ Sutter, C. and Ziefle, M, 2005, Interacting with notebook input devices: An analysis of motor performance and users’ expertise, Human Factors, 47, 1, 169-187.
  10. ^ a b Office work places with laptop computers: User specific requirements for input devices and software design Sutter, Christine Department of Psychology, RWTH Aachen University
  11. ^ Sutter, C., Ziefle M. How to handle notebook input devices: an insight in button use strategy. Contemporary Ergonomics 2003, pp241-251 google books
  12. ^ from FOLDOC
  13. ^ nipple mouse: Information and Much More from Answers.com
  14. ^ Slashdot story with references to "clit mouse"
  15. ^ a b XKCD comic referring to multiple names for controller

[edit] External links

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