> Why is it necessary to disable keyboard interrupts during scrolling ? Does
> it just look jerky on the screen, or is there some really crucial reason ?
> It still might be better to just have it working reliably without crashing,
> even though the scrolling might not look quite as smooth (which then could
> be blamed on Apple :-).

It's more complicated than that.  When we get a keystroke, we really
can't act on it right away because we'd be doing too much in the
interrupt handler of the keyboard.  So we put it in a queue, and the
next timer interrupt actually pulls the keys out and sends them to the
right place.  The timer interrupt sets some spl level and the screen
scrolling happens at that level.  We could drop the level down to 0
just before scrolling, but then we might run into all sorts of other
problems that the spl was trying to avoid (like getting another timer
or whatever).

Lawrence

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