hdapm

A Mac OS X command line utility for setting the power management (APM) level for ATA hard drives.

It can be used to:

• eliminate "clicking when idle" noises exhibited by some laptop hard drives
• make a drive save more power and spin down more aggressively that in does with the default OS settings.

hdapm works by sending the "APM Level" ATAPI command to your hard drive - your drive must support this command for hdapm to work.

Compatibility

MacOS X 10.4 - 10.6. ATA/SATA hard disk with APM support. Does not work with USB or Firewire attached drives.

Downloads

Binary disk image (includes documentation)	hdapm.dmg
Source code	hdapm-source.tar.gz