Keyboard mapping characters with both shift keys

[Adam Williamson]

On Tue, 2009-05-19 at 10:42 -0500, Jud Craft wrote:
> Logitech wave multimedia keyboard here, L+R shift + t doesn't work.
> L+Rs + r does work.
> 
> Maybe it has something to do with the wiring of the keyboard (even on
> nice keyboards), that only certain groups of keys can send so many
> signals at a certain time.

This is essentially it. Here's some references...

http://www.dribin.org/dave/keyboard/html/index.html
http://www.extremetech.com/article2/0,2845,2301151,00.asp

this is usually a case of 'keyboard blocking', where certain
combinations of three keys pressed together are prevented from doing
anything in order to prevent 'keyboard ghosting' from happening. Some
high-end keyboards use the diode solution suggested by the first article
to prevent keyboard ghosting from being a problem, and hence don't
implement keyboard blocking, so all combinations of three keys should
work on these. Some keyboards also use a buffering system - Steelseries
keyboards claim to allow you to press every key on the keyboard
simultaneously...

http://www.amazon.com/SteelSeries-64022-7G-Keyboard-Black/dp/B000W6IY6O
-- 
Adam Williamson
Fedora QA Community Monkey
IRC: adamw | Fedora Talk: adamwill AT fedoraproject DOT org
http://www.happyassassin.net