If you have a PC or a server passing of the time with no activity on the disk, can save a little on the electricity bill if the halt. It's true that can make configuring power management on your desktop environments (KDE, Gnome, etc.) but what I present here is a simple and rapid method for manually configuring this mechanism, ie the operating system Bash. The tool to use hdparm is used to but to suspend the operation of hard disks can also adjust parameters of cache, DMA, or even acoustic noise,...