Power Management

["Tom Geman" <openbsd_car_(_at_)_hotmail_(_dot_)_com>]

I am in the planning stages with the hopes of installing OpenBSD in my car.  
I have ordered a Via
Epia MII motherboard 
(www.viavpsd.com/product/epia_MII_spec.jsp?motherboardId=202), and I
am hoping to install openbsd on a 1-3 GB CF card.

I would like to hook up the motherboard so that turning the ignition on 
starts the computer, and
turning off the ignition shuts down the computer, gracefully.  Since I won't 
be the primary driver
of this car (that goes to my wife), I want this shutdown to be 
non-interactive.

I have found mp3car.com as a very useful reference, and it appears that 
there are simple circuits
that will wire to the iginition and the powerbutton controller on the 
motherboard and take care of
the powerup stage.  Unfortunately, I can't see the circuits useful for 
shutting down the computer,
since  I believe they require ACPI compatible OS's.

I won't be using a hardrive, just the CF card and probably a USB thumb drive 
(for mp3's).  I will
however also be running other applications that require writing to the CF 
card (or USB drive).  This
'data writing' eliminates the solution of just cutting the power without a 
shutdown since I do not
want to lose data. Correct me if I am wrong.

A similar problem was brought up in this thread
(http://archives.neohapsis.com/archives/openbsd/2002-08/1467.html),
but was limited to a solutions that won't be effective in this case, and my 
motherboard doesn't
seem to support APM like openbsd does.

So far the closest solution I have is using a shutdown circuit that will 
send a signal via the serial
port for my computer to shutdown. (http://www.dashwerks.com/dw_dssc.php)

Does anybody have any suggestions on how I can accomplish this task?

Maybe using a CF card and USB drive allows me to poweroff without shutting 
down ?
Maybe the VIA EPIA MII understands APM ?
Is the solution I suggested the only possible way ?

Thanks for any input,
Tom

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