Spin Down Hard Disk Programmatically on Windows?
How do you request Windows to spin down a hard disk programmatically? Is there any user-mode function I can call (or kernel-mode function to call or IRP to send) in order to make this happen?
I've tried making a program to send an ATA STANDBY command directly to the hard disk, but the problem is that this method doesn't inform the system, and hence whenever the system needs to flush the cache, it'll wake up the hard disk again. How do I tell the system to do this for me? (If the system does it, it'll save up the cache and "burst" the data when it gets too large, instead of writing in small increments.)
(The entire point here is to do this directly, not by changing the system-wide spin-down timeout to a 1-second period and waiting for the disk to spin down. I need a function I can call at a specific moment in time when I'm using my laptop, not something generic that doesn't suit 95% of situations.)
How far I've gotten so far:
I have a feeling that PoCallDriver and IRP_MJ_POWER might be useful for this, but I have very limited kernel-mode programming experience (and pretty much zero driver experience) so I really have no idea.
Please read:
Update:
People seem to be repeatedly mentioning the solutions that I have already mentioned do not work. Like I said above, I've already tried "hacky" solutions that change the timeout value or that directly issue the drive a command, and the entire reason I've asked this question here is that those did not do what I needed. Please read the entire question (especially paragraphs 2 and 3) before repeating what I've already said inside your answers -- that's the entire difficulty in the question.
More info:
I've found this document about Disk Idle Detection to be useful, but my answer isn't in there. It states that the Power Manager sends an IRP to the disk driver (hence why I suspect IRP_MJ_POWER to be useful), but I have no idea how to use the information.
Answer
I hope this helps:
This: http://msdn.microsoft.com/en-us/library/aa394173%28VS.85%29.aspx
Leads to this: http://msdn.microsoft.com/en-us/library/aa394132%28VS.85%29.aspx#properties
Then, you can browse to this: http://msdn.microsoft.com/en-us/library/aa393485(v=VS.85).aspx
This documentation seems to outline what you are looking for I think.
P.S. Just trying to help, don't shoot the messanger.