Calvin
Wed Jun 01 02:31:38 CDT 2005
I guess it needs a driver to read the signal from the accelerometer and the
it would need to send a command to the storage driver stack to stop the HDD
when it determined the notebook is falling or the acceleration rate is not
in a safety range.
I did a similar project in school long time ago (but it's nothing to do with
notebook). In my experience, correctly processing the input signal from the
sensor is very important. In order to prevent the protection mechanism from
mis-engaging, I would let the signal go through a low-pass digital filter in
forms of Finite-Impulse-Response (FIR) system or Infinite-Impulse-Response
(IIR) system. IIR is easier to code but I would prefer FIR since it's
guaranteed to be convergent while IIR tends to be instable due to
accumulation of computational errors. Carefully adjust the sampling rate
and pass band of the filter until it accurately catch the real dangerous
situation while ignore all other light vibrations. If you are not familiar
with digital filtering, you may read some undergraduate level text books on
"signal and system", or some graduate level books on Digital Signal
Processing if you prefer. But those books are generally too academic, I
think there should be some for engineer.
This would be an interesting project. I wish I had such a protection on my
notebook although it doesn't fall quite often.
HTH,
Calvin
--
Calvin Guan Windows DDK MVP
Staff SW Engineer, NetXtreme MINIPORT
Enterprise Network Controller Engineering
Broadcom Corporation www.broadcom.com
"Anthony Winner" <Anthony Winner@discussions.microsoft.com> wrote in message
news:43736259-A6FD-4DD6-B12A-21C786C10D03@microsoft.com...
> Does anyone know how it works, I know the basics, there is a
> accelloromitor
> that signals the system and it shuts down the disk. But what is the
> plumming,
> does it take a driver to do it, or is it just the app making IOCTL calls
> in to
> the disk driver, and if so which ones....