What happens when a hard drive shuts down!?

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drake2231's picture
Joined: 06/17/2009
Posts: 51

Many moons ago, when I worked at Worstebuy, I heard my boss use a sales pitch to sell an AVR with battery backup. He said that if the power goes out, and the HDD is suddenly without power, then it won't be able to power itself down properly and is bad for the drive physically.

First thing I thought is Boulder Dash! Sounded like a total lie. Anyways, I was thinking about it, and I was wondering if there was anyone out there who actually knew what a HDD does when the computer shuts down normally. Does it use power to slowly deaccelerate? Or does it just cut the power and let it self stop spinning on its own? I would guess it just stores some boot information, cuts the power, leaves it some cab fair, and leaves it to stop moving.

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Hardware_Hank's picture
Joined: 12/13/2010
Posts: 43

well, I mean I've had to manually power down my rig a few times and one of my HDDs that I kept from a few builds back still works 5 years later from the "abuse" so take it or leave it. Most HDDs can adapt to it but its still recommended to power down the correct way to save any windows settings.

Joined: 04/21/2002
Posts: 102

First thing is knowing the fact that you must replace it.
Backup your data if you get it to run if not rebuild your computer by inserting a new Hard Drive and putting the hard drive that is causing the problem as a slave or external enclosure to access the files you need and then throw it out. Litteraly.

Need For Speed

Joined: 10/14/2010
Posts: 262

Modern harddrives don't need to be shutdown properly. I bet your boss was just making up stories trying to sell expensive backup power units.

When an HDD powers down, it just stops spinning and the head moves back to the side of the drive where it locks into place (to prevent the head from crashing into the platter during transportation). I remember very old drives needed a command (and thus power) to lock up like this, but today all drives are designed to lock up automatically when the power is cut off.

dustyschaffner's picture
Joined: 06/02/2009
Posts: 334

It doesn't really cause any short term problems but if you do it continually you WILL lose OS information and eventually end up with the blue screen.

Only difference between proper shutdown and sudden shutdown is this:
Proper: All data is finished writing then all data transfer stops, the needle parks, and the PCB applies a dynamic brake to the disks in motion to slow them down.
Improper: All data transfer is interrupted, needle automatically parks and no braking mechanism is applied to the disks. But sometimes the needle doesn't always park correctly when it is suddenly shut down and I think that is the second reason why drives may crash.

Joined: 04/21/2002
Posts: 102

Drake is not even answering back is only us in this topic, lol.