mo at ccr.org
Tue Feb 5 15:24:07 CST 2008
Richard O'Neill wrote:
> I have a question for the group. While listening to a pocket AM band radio I happened to walk past my new ACER WiFi laptop (preloaded with VISTA) and heard a loud buzz on the radio. This was a surprise since the laptop was powered off and power cord disconnected.
> After removing the computer battery the noise went away. Does anyone have any idea what battery power is being expended for? What's this machine up to? Hmmm ... perhaps something secretly nefarious for Microsoft ... or the Chinese government?
> Please don't tell me it's reporting to Homeland Security.
> The subject is more than academic since my laptop is often unused for weeks to months at a time and I wouldn't want to find a drained battery the next time I took it on a trip.
> Richard O'Neill
> Tacos mailing list
> Tacos at amrad.org
you didn't say how the machine had been shut down.
the answer to that matters a lot.
take the battery *out* if you don't want it discharged.
there's a little springhead in there that keeps on ticking
(slowly and in spurts) to watch for button presses, maybe
incoming ethernet or wifi packets. and that will chew
through the battery eventually.
the modern processors have a whole raft of "states" which
turn off more or less of the machine, and then the whole
laptop has a set of "modes" which can be enabled
or disabled). some keep the processor registers alive,
others dump cpu state to ram and then keep the ram alive,
others copy everything to disk and put it in deep sleep.
then there's "real shutdown" where all the toys are
picked-up and put away for the next time.
understanding precisely what your laptop does when
you just close the lid, or sleep it and then close
the lid, and what might happen an hour later when
it decided you really aren't coming back are
all part of the crazy world of "power management."
More information about the Tacos