A question about spinning down HDDs...

I've noticed with some HDDs that they emit a worrying noise if you just cut power to them rather than let them spin down after a command from the OS, if you pull the battery from a laptop or switch of an external caddy for example and it seems much more noticeable in 2.5" drives. Here's a recording of a HDD dock containing a 2.5" Samsung drive being switched off if you don't know what I mean. I'm assuming this is an emergency head park which I've read (here, for example - search for 'emergency unload' in the document) is more damaging to the drive than a graceful power-down, does anyone know if this is true or just yet another computer myth? Also after giving this some thought I've been using hdparm -y on Linux where possible, just to be safe, is there anything similar on Windows (if it's needed, that is)?

Edit: Oh and I know it probably doesn't matter all that much, I just thought it would be something interesting to post and maybe it does effect long-term reliability?

when the power cuts, the read heads are supposed to dock realy fast incase they smack into the platters.. ie dropping the hdd or some other incident.

I think you can hear the read heads smashing to home......

In that recording the click-click is the power switch btw, I should have mentioned that. Yeah HDDs use various methods to return the heads in the event of a power failure but I was wondering if they're designed to do it all the time or if, like that pdf says, it can cause damage over time.

Emergency unload only applies when you're reading or writing from the disk at the time of the power down, or the G-sensor telling the drive to. Many HDDs park the head by default when idling so the use of emergency unload is minimal.

In situation that needed emergency unload, NOT unloading it will cause more damage, so it is the lesser of two evils.

I personally have thought that HDDs are not reliable anymore and is not expected to. That is where fault tolerance comes into the game.

Laptop drives commonly park the heads when the disk is idle, as well as some 3.5" drives like the WD Greens that had the feature/bug that wore them out more quickly by parking the heads every 10 seconds or something the the OS would access the disk causing them to unload again, but most desktop drives don't park the heads when idle.

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Originally Posted by watercooled

Laptop drives commonly park the heads when the disk is idle, as well as some 3.5" drives like the WD Greens that had the feature/bug that wore them out more quickly by parking the heads every 10 seconds or something the the OS would access the disk causing them to unload again, but most desktop drives don't park the heads when idle.

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All recent Hitachi drives too, have unload idle that reduce idle power by an extra 2W.