How can hard drives go bad?

Who knows? When I first had my computer, my hard drive dropped dead after only a couple of months!

Well, let's see if we can get some answers, as it is expensive and difficult to switch over to a new one, without standing on one's head or losing data.

Ok, I did a little sleuthing. Seems that heat, shock, water damage are prime causes of hard drive failure. I know someone who builds computers. He always puts extra fans in the case, to keep everything nice and cool.

An article that I saw cites fragmentation as a cause of failure. If the head has to keep moving around to search for something, it will wear out faster. So use your defrag often!

A hard drive is a spinning (FAST! 7200+ RPM) metal platter with a magnetic pick-up (similar to an phonograph tone arm and stylus) that "reads" and "writes" the data.

The head on that pickup rides on a cushion of air between it and the drive platter that creates a gap that is only a few nanometers wide. Bumps during drive operation (i.e. kicking the PC..) can cause the head to grind against the platters. Even small particles of dust or smoke can get into the drive case and they are larger than the air gap.

Any time there is contact some of the oxide on the platters comes off which creates more dust within the drive case. More dust creates more contact so you end up in a death spiral. The more the drive spins (as it does when heavily fragmented as Phoenix mentioned) the sooner it wears out.

For the most part hard drives are pretty reliable but manufacturers do try new production techniques and some of those end up failing badly down the road (Seagate had this very problem several years ago..) but for the most part buying a drive is a crap-shoot. You have no way of knowing the condition of the drive when you buy it and many production problems won't show up for a year or two.

Heat and cold can cause problems with expansion and contraction, you can have electrical component failuers in the drive circuitry, you can have a catastrophic failure if a drive is dropped and the small arm breaks, or you can simply wear away the media to a point where the drive is no longer reliable. All are real possibilities...

Good post fishin' - here's some relevant stuff from How Stuff Works.com

How Hard Disks Work

What does it mean when a hard disk has a head crash?

What is the churning sound I hear from my hard drive whenever it is retrieving data?

How PCs Work

When you delete files from your computer and after you empty it out of the Recycle Bin, where exactly does it go?

How Bits and Bytes Work

Boy, this is interesting stuff. Thanks guys ;-)

I blame their parents.

LOL!