I push my Mac real hard at times. When the disk is thrashing hard, I’ve noticed a program called spindump that’s running. Here’s what the man page says:
spindump is a tool used by various system components to create hang reports and notify the user of application hangs. … For normal application crashes spindump will display a dialog to alert the console user to the crash and offer the choice to view more details about the crash and/or report the crash to Apple.
sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.spindump.plist
After running this, I don’t see spindump, and the disk isn’t thrashing as hard. Yeah, I’m running two heavy virtual machines that are hammering their virtual disks, but it appears that I’ve gained something.
2009-03-27 Update: Fixed typo. A huge thanks to Rob for catching that.
2011-02-23 Update: It was suggested that I also mention how to reverse this. Use load instead of unload.
sudo launchctl load -w /System/Library/LaunchDaemons/com.apple.spindump.plist