Hdparm

hdparm (hard disk parameters) is a CLI application to configure ATA/IDE hard disks.

There are many options that can be set, see the man page for a full list. Note that some options can be harmful and can cause data loss or complete system lockups. So: Use at your own risk.

Example usage
Check the current settings for the first hard disk: General harddrive information: Benchmark (useful to compare after tweaking some settings): Set the spindown time to 30min: Force a hardisk into standby mode:
 * 1) hdparm /dev/hda
 * 1) hdparm -i /dev/hda
 * 1) hdparm -tT /dev/hda
 * 1) hdparm -S 241 /dev/hda
 * 1) hdparm -y /dev/hda