Re: Poor tasking performance

["Björn Persson" <spam-away@nowhere.nil>]

Robert I. Eachus wrote:

> And finally we are back to polling for some devices because the overhead 
> is lower than using interrupts...

I can imagine that, but I doubt the keyboard is one of those devices.

> For keyboard input most systems, most of the time, use a protocol where 
> _some_ keys cause interrupts, and others just place the data in a 
> buffer.  When the carriage return or whatever occurs, the entire buffer 
> is read.

When I press a key, in most cases either a character shows up on the 
screen or some action is triggered. I suppose modifier keys (Shift, 
Ctrl, ...) and "dead" accents could be buffered. Right now I can only 
come up with one case when letters don't have to be read immediately: 
when the user is typing a password and characters are neither echoed nor 
indicated with asterisks.

-- 
Björn Persson

jor ers @sv ge.
b n_p son eri nu