On Tue, 16 Oct 2001, Ken Ambrose <[EMAIL PROTECTED]> wrote:
>
> It does -- most certainly. I've been in *DOS*, doing *NOTHING*, and the
> fans come on on my Sony. Beats the hell out of me what's going on. Boot
> to Linux, and, after the initial kernel load and boot, the fan's off
> within 20 seconds. Go figger. (I've also observed similar behavior in
> other notebooks, and all flavors of Windows.)
The OS can send the CPU the halt instruction (I think it is called HLT
on Intel) when there is no work to do. This saves power. Early
versions of DOS and Windows didn't do this, they just let the CPU run
full bore. At some point Windows switched over to using the HLT
instruction, I don't know when, but as a pure guess I'd say Win98.
BTW, distributed computing projects like distributed.net say things
like "put your wasted CPU cycles to use!". Well, having the CPU
non-idle actually does cost more money in the extra power it uses. Not
a lot, but it is not really completely free as they seem to be
implying... I don't know if 20 Watts is a good estimate for how
much power is saved by idling the CPU, but if so that is about $20/year.
That's not much, but if you have SETI running on 100 lab machines at
a university, that's maybe $2000/year...
Linux kernel does the intel HLT stuff in the file:
<linux_src>/arch/i386/kernel/process.c
**********************************************************
To unsubscribe from this list, send mail to
[EMAIL PROTECTED] with the following text in the
*body* (*not* the subject line) of the letter:
unsubscribe gnhlug
**********************************************************
