emergency parking noise??

Hi,

I'm running a dual-boot toshiba laptop (an M55); when I shutdown under winxp, everything powers off quietly. But, under linux and bsd, both, at the very last moment, a sort of "dying beep" comes from the system at the moment the machine powers off. It will also do it if I hold the power button before the bios/cmos stuff finishes up, before it hands over to the hd. Someone told me that it's the sound of the hard disk doing an emergency park, and that it's a bad thing.

I'm confused...oh, I also tried taking out the hd, and firing it up, and powering off during the bios/cmos stuff. It powers off silently, so it must be a hd sound.

I'm ignorant of hd parking procedures, so any advice/help would be GREAT.

Thanks,
Dan