martin@duskware.de (Martin Husemann) writes:
> On Mon, May 03, 2004 at 10:02:48AM +0200, Alan Barrett wrote:
> > This looks useful.  I have also been playing with a daemon that checks
> > the load average every minute and cranks the CPU speed up or down.
> 
> And watch temperature and tune fans?

Being a computer, it might be able to do better than a simple
closed-loop system.  As a frill, it might be nice to also store the
last fan RPM's needed to maintain a certain temperature.  That way you
wouldn't have to wait for the temperature sensor to equilibrate before
you could crank the fans to the right speed.  It is important to note
that some external temperature probes used to sense CPU temperature
and motherboard temperature can lag the actual temperature by quite a
long time.  By the time the computer reads a certain temperature,
things have gotten quite a bit worse.

Expensive industrial whole building temperature controllers
essentially do a refined version of that hack.  They build up a table
of steady-state outside and inside temperatures and the
heating/cooling inputs needed to maintain that.  They then use that
value to predict what the inside temperatures really is after a step
function is applied to the heating/cooling system.

-wolfgang
-- 
Wolfgang S. Rupprecht 		     http://www.wsrcc.com/wolfgang/