making an ide hd sleep

[Marcelo Borges Ribeiro]

Hi, I´d like to know if it's possible to put an ide hd to sleep after (for
example) 15 min. idle (i don´t know if an hd under linux stays  idle that
amount of time. ). I tried mount -o noatime and hdparm -S 150 /dev/hda, but
it seems that when it sleeps it starts working after a few seconds (when it
sleeps!). Is there a way to have this feature under linux?

Thanks in advance,
Marcelo Ribeiro