Re: RAM size.
On Fri, Jul 13, 2001 at 12:13:20PM +0100, J.A.Serralheiro wrote:
> On Fri, 13 Jul 2001, Alexey wrote:
> > You know, while running DOS or Windows, the CPU is hot (I can touch it),
> > even if I do nothing. It becomes cool under Linux!!!
>
> strange, never heard of that.
Linux (and NT, incidentally) sends HLT (HaLT) instructions to the CPU
telling it to shut itself down (until the next interrupt) when there's
nothing for it to do. So if your linux system tells you you're at
30% CPU utilization, the CPU is essentially turned off 70% of the
time.
DOS, Win3.x, and Win9x aren't that smart. They don't use HLT - I
suspect they send NOP (No OPeration) as an idle, but I'm not certain.
Instead of turning off the processor when there's nothing for it to
do, they have it twiddle its thumbs. Even at 1% CPU utilization,
these OSes keep it running 100% of the time.
I would guess, based on their respective legacy codebases, that Win2k
uses HLT and ME/XP don't, but I haven't heard anything definite about
them to date.
Reply to: