Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!magnus.acs.ohio-state.edu!csn!news.den.mmc.com!magellan!doehr
From: doehr@magellan.den.mmc.com (Brett B. Doehr)
Newsgroups: comp.human-factors
Subject: Re: Track ball on a keyboard?
Message-ID: <1991Jun12.181324.12617@den.mmc.com>
Date: 12 Jun 91 18:13:24 GMT
References: <91163.083144CJS@psuvm.psu.edu> <2909@sumax.seattleu.edu>
Sender: doehr@magellan (Brett B. Doehr)
Organization: Martin Marietta Astronautics Group
Lines: 42
Nntp-Posting-Host: magellan.den.mmc.com

In article <2909@sumax.seattleu.edu>, bentson@sumax.seattleu.edu (Randy+Cindy Bentson) writes:
|> Christopher (or whoever wants to enlighten me):
|> Well, I for one am ignorant but intrigued. I have used both
|> the cursor arrow/hjkl keys and mice, and am curious
|> about these track balls. How do they work? Will my experience with
|> them be the - gosh, how to put this into words? - line by line
|> (like Etch-a-Sketch) movement or a more subltle flowing movement
|> that puts you where you want to be "instantly" - like mice do?
|> 
|> The idea of having something on the keyboard is attractive (I
|> always lose the mouse, or have no reasonable surface to run 
|> it on). What other advantages are there?
|> 
|> Cindy B.

The advantages seem to be not needing the surface space to move 
the mouse and not having to move your hand from the keyboard to
move/use the cursor/pointer.  The disadvantages may be a larger
keyboard to deal with, less precision in moving the cursor/pointer,
and having to shift the hand to click the trackball buttons.  The
concept is (if you have a mechanical mouse as opposed to an optical
one) similar to lifting the mouse up and moving the "mouse ball"
with your fingers to move the cursor.  They are popular with the
portable computer industry and also with space applications like
shuttle and space station.  In zero-gravity, a mouse would float
at the end of its cable, you may accidently click a mouse button
when grabbing it, etc.  A trackball is a ball mounted in the keyboard
by being seated under a hole smaller than the ball's diameter, so it 
cannot float free but can be spun with the palm.

Hope all of this helped to enlighten you.  If you still can't 
visualize the concept, go to your nearest video arcade.  Many
games now use them 8-).

--Brett.

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Brett B. Doehr           Martin Marietta Astronautics Group |
Voice: (303) 977-1504           Internet: doehr@den.mmc.com |
Fax:   (303) 977-1530               America Online: BrettBD |
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