Quoting Hans Petter Selasky <hsela...@c2i.net> (from Mon, 27 Sep 2010 14:21:42 +0200):


I was thinking about adding a sysctl to ukbd and ums that shows how many
keypresses have been done and how many pixels you have moved the mouse during
a day. These number will mostly be useful for making ergonomic arguments that
a certain way of working is better than another one.

Anyone have any comments or input on this? Are there any security concerns
about this?

Be careful with ergonomic arguments. For example the screen corners are easy (and fast) mouse targets (if they are used for something in the software), and would give a false impression if you count mouse-device movement instead of mouse-pointer movement on the screen (which you can not measure in ums). The most easy ergonomic point for a mouse is the current position (pop-up menus), and this involves not much movement...

Regarding key-presses there's also the problem of having the keys directly under your fingers, or having to move back and forth with the hands (also depends upon the keyboard layout and type of work you do).

Regarding metrics I suggest to:
 - add a click-count
 - not hardcode the counter-reset (let a sysctl handle the counter reset
   upon request)
 - differentiate between normal key presses and shift-ed/control-ed/...
   ones (I do not think that caps-lock should count as shift-ed)
 - I do not know if it makes sense to have a hold-time (for
   shift/control/...), if this is for real ergonomic research,
   this could be helpful

Regarding the security:
 - don't make this real-time stats, add some artificial delay
   (you could interpolate what is typed just by watching the
   stats), I suggest to make the delay at least several
   seconds long (to cover people with disabilities and maybe
   people which search each character with one finger), for
   real ergonomic research this is counter-productive (but
   you stated that you want to measure on a per-day basis,
   to this should not matter in your case)
 - make it depending on a compile time knob (disabled
   by default) and issue a warning on device attach if
   compiled in


An honest tale speeds best being plainly told.
                -- William Shakespeare, "Henry VI"

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