How to spin down hardisks is OS X, without energysaver ?

Kimmo Hamalainen wrote on :

Is there any way to spin down only some hard disks in OS X ? Energysaver put all hardisks to sleep but thats not what I want. I like to keep my internal hard disks running 24h but external hardisks should be off at night.

In linux I can use hdparm and NetBSD uses atactl command to do this trick but how to do this in OS X ?

Charles Martin replied on :

In article Pine.LNX.4.44.0201250930520.4810-100000@redacted.invalid, Kimmo Hamalainen robin@redacted.invalid wrote:

Is there any way to spin down only some hard disks in OS X ? Energysaver put all hardisks to sleep but thats not what I want. I like to keep my internal hard disks running 24h but external hardisks should be off at night.

In linux I can use hdparm and NetBSD uses atactl command to do this trick but how to do this in OS X ?

try typing "man atactl" in the terminal of Mac OS X and see if that command is available.