Save battery power

• Difficulty: Intermediate
• Application: hdparm

You are probably familiar with using hdparm for tuning a hard drive, but it can also save battery life on your laptop, or make life quieter for you by spinning down drives.

hdparm -y /dev/hdb
hdparm -Y /dev/hdb
hdparm -S 36 /dev/hdb 

In order, these commands will: cause the drive to switch to Standby mode, switch to Sleep mode, and finally set the Automatic spindown timeout. This last includes a numeric variable, whose units are blocks of 5 seconds (for example, a value of 12 would equal one minute).
Incidentally, this habit of specifying spindown time in blocks of 5 seconds should really be a contender for a special user-friendliness award - there's probably some historical reason for it, but we're stumped. Write in and tell us if you happen to know where it came from!