spinning down disk when needed

["H. S." <greatexcalibur@yahoo.com>]

I have a second hard disk /dev/hdb which has nothing installed on it and 
is used only for video data. So I uses it only a few hours a week.

I am wondering if I can spin it down when it is not mounted or when not 
being used and spin it up when needed. Any wepages or packages in Debian 
that can do this?

thanks,
->HS