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RE: Key combinations and audio feedback.
> I think I've created a monster.
No, just discovered a "feature" of the keyboard scanning hardware.
The keyboard doesn't have 'n' key rollover, any three key combination
that the keyboard scanner can't figure out which keys are really
pressed causes it to send a beep to the speaker to alert you that
it probably just lost one of your key strokes.
This takes a bit of imagination but if you look at the keyboard
as a series of vertical rows (slanted to the left) and horizontal
rows it forms a grid. A vertical row is composed of the keys
1-Q-A-Z-Alt, the next one is 2-W-S-X-SPACE, moving one key to
the right until you get to the end. The horizontal rows are
1-2-3-4 ... and A-S-D-F... etc.
Ok, now imagine this as a grid and pick any 3 keys that would
touch three corners of a square. If you realize that the way the
keyboard is scanned is by turning on a column line and looking
at the row lines, you'll notice that when the three corners of
a square are pressed, there is no way to figure out whether or
not the key that would make up the fourth corner is also pressed.
Now on cheaper keyboards this is sometimes called the frlom bug.
If you look you'll see that F-R-O meets the criteria above and
when the scanner gets confused it doesn't know whether or not you've
pressed the 'l' key. On a cheap keyboard it just sends an L press
since you might have pressed it. People two try to type "from" to
fast get "frlom" in the input stream. Not so our trusty ThinkPad,
it beeps to tell you that it has no idea whether you're pressing
O or L so it sends neither and beeps at you.
--Chuck