Laptop hard drive spindown timeout

[Nate Clark]

I'm surprised at how well 5.1-RELEASE is working on my IBM
Thinkpad 600X, with the exception of one annoying problem.  When I'm
running from batteries, the hard drive spins down every second or so.  Of
course this is usually followed by some disk activity requiring it to spin
up again.  So my drive is in a constant state of spin down/spin up.  All
I can think of is how much this is shortening the life of my drive.  This
doesn't happen when on the AC adaptor.  Needless to say, I never run on
batteries, which kinda defeats the purpose of having a laptop.
I'm not using APM or ACPI, although my troubleshooting with these enabled
has had no effect so far.  Any ideas about how to fix this?  I don't mind
doing a little kernel or device driver hacking if need be. Actually, I'd
enjoy it, just don't know where to begin.

~$ uname -a
FreeBSD bart.int.jope.net 5.1-RELEASE FreeBSD 5.1-RELEASE #12: Sat Oct 25
22:21:09 PDT 2003
root at bart.int.jope.net:/usr/obj/usr/src/sys/OLDCARD_BART  i386


--
Nathan Clark
http://www.jope.net/~nwc/resume