I have been trying various options with hdparm, like setting the spin-down time to 5 minutes with
hdparm -S 60 and setting the APM to 1, but I end up getting a spin-down in less than 5 seconds... How do these values combine to end up in a spin-down time?

According to Western Digital support:

Thank you for contacting Western Digital Customer Service and Support. My name is Esther.

I apologize for the inconvenience, I will be more than glad to assist you. The WD Black internal hard drive doesn't have a utility that can be used to adjust the drive's spin down time.

Unfortunately, since you're using a third party application (HDPARM) to adjust the drive's spin down, we're unable to provide any information on how to properly set the parameters on the utility. We would recommend contacting the manufacturer of the application.

If you have any further questions, please reply to this email and we will be happy to assist you further.

I need to get some more useful information from my drive manufacturer about this.


The spindown time -S 60 is equal to 5s*60 and corresponds to 300s. The APM levels -B 1-127 (permitting spindown) and -B 128-254 (not permitting shutdown) are more or less passed directly to the disk and hdparm doesn't do any further computation on those values.

The exact behaviour of those values is unspecified and left to the drive manufacturer. Therefore hdparm can't document what they do.

  • Okay Marco, anything to say about my recent edit? – Shane Dec 18 '14 at 7:24

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