Thanks a lot for clarifying. Cheers, CP
Peter Hunkeler wrote:
AFAIK, windoze continually interrupts its execution to check whether the
mouse has moved, whether a key has been hit (which would count as I/O or
'graphics') or whether another has to be dispatched etc.
Off the three above only the last is true. The mouse device and the keyboard
device generate hardware interupts which interupt the processor. So Windows
(and other OSs as well) don't need to poll, but are notified by the hardware.
Each time a key is pressed, or released, an interupt is generated. After the
key is pressed, and that interupt has been generated, the keyboard repeatedly
generates interupts as fast as the keyboard repeat rate tells is. The mouse
generates upon mous button press and release. The mouse movement interupts are
generated whenever the mouse has been moved a certain distance that depends on
the mouse resolution.
The latter, mouse movement, it the most resource consuming of all the above. I
remember well Solitair I used to play on Windows 95. The cards were jumping
over the screen drawing nice pictures one you succeeded. The cards moved quite
fast to present an nice animation. You could slow down, and even bring it to
almost starve, when you moved the mouse fast and faster. That was a good
visualization on how much resources supporting a mouse may consume.
--
Peter Hunkeler
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