[pwrmacg4]

In System preferences/Energy Saver, when I select put computer to sleep, but disable sleep hard drive when possible, does hard drive go to sleep? how soon? is it bad to keep waking/sleeping hard drive every 30 minutes?

[64stang06]

When the computer is asleep, everything is asleep.

[slpdLoad]

That check box just lets it spin down the hard drive when you're not actively reading or writing to it.

[mkerr64]

is it possible to make it run ? or is that just defeating the purpose of sleep?

[Chuckit]

Originally Posted by mkerr64 

is it possible to make it run ? or is that just defeating the purpose of sleep?

It's pretty much defeating the purpose. Sleep is a power-saving mode — hard drive motors are a big power drain. I've heard some debate over the actual virtues of leaving a hard drive running vs. spinning it down when not used, but I don't think there's any consensus that spinning it down is particularly horrible. I doubt Apple would include the option (or at least would include a warning!) if it seemed likely to break their hardware and increase repair costs.

On the other hand, a hard drive is more likely to break when it's being spun up. This isn't because spinning up is so bad for the drive, but because the drive was already on the brink and problems often expose themselves at spin-up time. The positive side of this is that your hard drive can watch its spin-up time for any changes and give you an early warning.