Why your hard drive died

Working as a desktop tech in an organization that services not only enterprise systems, but also all the computers that students bring to the campus, I see a lot of hardware failure – the most common of which, by far, is hard drive failure.

I often get asked questions about this from the perplexed users.  Most notably is, “How did this happen?” or the slightly accusatory cousin, “What – do parts like this just die on their own?”

As a matter of fact, they do… and here’s why.

Imagine if you will, a record player.

Under 30? Here you go.

A record player operates by spinning the information-carrying-medium (in this case, a vinyl pressing of analog bumps and grooves) at 78 RPMs.  That is, Revolutions Per Minute.  This means that by the time your 1-minute egg is done cooking, the record has spun a total of 78 times.  That’s plenty fast, considering the following:  there is a needle gently pressed into the record which reads the information coming from the medium.

Like this.

A lot can go wrong here – a bump of the table, some scratches on the record, an errant dust-bunny lands in a bad place, the needle wears out, etc and you end up having to stop the music and make some adjustments.

Okay, so we have the basic nature of the spinny-needly bit.  How does that relate to your hard drive?

Imagine if you will, a very special record player.  This one does not spin at 78RPM.  This one spins at 7,200RPM (or 5,400 if you were a cheapass when you bought your computer).  The medium is not a vinyl pressing, but rather an aluminum alloy with a magnetic material coating we call a “platter”.  As unforgiving as a record can be about dust and scratches, the platter is a downright bastard about such things.

But wait – if it can’t be scratched, how can the needle read the information from it spinning that god-awful-fast?  Ah!  Here we go – this is because a needle isn’t used.  Instead, a digital reader called a “head” is attached to the arm and that is what reads the data.

But how does it do this without scratching the platter?  Simple – it doesn’t make contact while the platter is spinning.  See, the air caused by the spinning platters actually lifts the head up between 5 to 10 nanometers (the thickness of a human hair is around 50,000 nanometers).  This allows it to read the magnetic data from the platter without damaging it.

So where does it all go wrong?  Well jeepers, man – where doesn’t it go wrong?  You have a record player spinning just under 100 times faster than the one in your parent’s attic… you have a “needle” that is constantly floating above on a microscopic pocket of air, and it’s all being tossed around helplessly in your backpack.  Either that, or you have a system crash that causes it to go from gently spinning down to putting on the emergency brakes.  There are plenty of protections in place to help with the bangs and bumps that computers today endure, but the fact is, it’s a crazy mechanical system that has to continually go just right, or it’s dead.

So what do you do?  Well, there’s a few things.

1.  Wait to move your laptop around a few moments after shutting the lid.  When you close the lid, the system is still active.  It knows that it needs to go to sleep, but it requires a drink of water and a bedtime story – it has to prepare and make itself safe to move around.  Give it that time.

2.  Never just pull the plug (hold down the power button for a hard power-off).  Or at least, try to do it as little as possible.  This really is an emergency maneuver and should be treated as such.  I’ve known people that did it constantly as a fix for “it was being slow and stupid”.  Not good.

3.  Know that it will happen and prepare for it.  It is a very rare delight when a user comes in and says, “I think my hard drive died and I need help buying a new one.  No sweat on the data – I HAVE A BACKUP“.  Hard drives are not that expensive – usually a decent one will run between 60 to 120 dollars.  It’s not that big of a deal – where the panic sets in is with the data.  For god’s sake, man – back up your files! Use CDs, DVDs, USB Pendrives, or even better, external hard drives that you only ever plug in to perform occasional backups on… whatever it takes, just have your stuff in more than one location.

So there we go.  “Why did my hard drive die?” can now be replaced with “Here’s my new drive – can you help me restore my files from my backup onto it?”



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