Why Magnets And Computers Don’t Mix

It’s normally an unspoken understood that magnets and computers shouldn’t mix.

But Why?

The other day we came across a computer for service that was absolutely covered in refrigerator magnets. The computer was having trouble booting and without having to diagnose it we could tell pretty quickly what the issue was.

Contrary to popular belief, magnets don’t actually affect most electronics. Though it’s not recommended, you can actually put a strong magnet next to a calculator, an iPhone or even a computer screen without any ill effects or at least not irreversible ones. The reason why computers are so adversely affected by magnets is because the hard drive that computers use to read data from are erased when they come in contact with a strong magnetic field.

Hard drives basically run on fires that right ones and zeros binary data to the discs that the computer can read. When that day comes in contact with a magnetic field is all zeros. The hard drive is effectively erased and along with it all of your data. This will stop your computer from working without a moments notice.

So while each refrigerator magnet on a silent computer may not produce a strong magnetic field to erase hard drive by itself, many of them together will absolutely destroy a hard drive over time. This is only for standard HDD drives. For solid-state or SSD drives magnetic fields don’t have the same affect on the information stored on the drive.

What’s most interesting about the ill effects of magnets on hard drives is that if you open up a hard drive inside there is a large powerful magnet inside to help write data to the drive itself. Now if you’re wondering how that’s possible, there’s two reasons:

  • First the actuator arm and right stated to the platters inside a moving hard drive self is actuated by electrical field that’s it uses the menace field to push off and move.
  • Second the magnet inside the drive is pretty well shielded so that it doesn’t have much effects on platters that it’s writing to.
  • The last reason but not very intuitive is that most magnets that have a north and south poles which creates a magnetic field that sort of looks like a figure 8 short infinities. This field propagates out from the center of magnets with a large reach. Hard drive magnets have four poles on North and South on one side and South and North on the other which creates a very small and very strong but not very big magnetic field. The resulting magnetic field looks like three small circles as opposed to the larger figure 8 pattern. The smaller magnetic field is easier to control and make sure that the data on drives is not affected by the magnetic field inside the drive.

Magnet inside computer =good

Magnet outside the computer = bad

If you’re having trouble with your computer’s data or need a hard drive data recovery please don’t hesitate to call your local data recovery experts at ITGuys


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