Sebastian Gottschalk <seppi@seppig.de> writes:

>> Signaling is not accessible by 'machine code' in a virus.

>It is. How do you think all those fan control software packages work?

There are several different implementations.

There are there were the BIOS controls the FAN directly and there
is no intervention of the OS.

And then there are those were the BIOS generates events for the OS
and the OS has to actively control the fan speeds.

On PCs this is all handled by ACPI; as an OS developer I have
worked on some of the ACPI codes and we did find systems which would
overheat and shut off when the OS does not handle this properly.

Unfortunately, we've found that there are systems were such a
hard off switch does not occur or not soon enough; and the system either
stops working or its lifetime is shortened.

Specifically in the realm of passive cooling the OS generally has a
say and if the OS ignores the BIOS (or a virus makes it ignore the BIOS),
this usually does not bode well the life expectency of the system.

Casper
--
Expressed in this posting are my opinions. They are in no way related
to opinions held by my employer, Sun Microsystems.
Statements on Sun products included here are not gospel and may
be fiction rather than truth.