There are degaussing devices that look like microwave ovens, and for all I know, that might be largely how they operate.
But outside of those, no magnet that you can hold in your hand will demagnetize a modern hard drive at any distance outside of the case, because there are magnets inside the case that are stronger than you can hold in your hands, and they’re used to move the head/arm assembly at mind-blowing speeds — and accuracy.
I have some old Imprimis Wren VII hard drive magnets still on my dad’s fridge, from the time when I did an internship there in 1989. I won’t say that you can’t remove them from the fridge, but they are stuck on there extremely well, and there are a number of people who had been injured by having their hand or fingers caught between those magnets and a ferrous metal object — like a fridge.
And that was 1989. The magnets they use now are much stronger.
Now, if you happened to put a hard drive inside an MRI machine, that would do the job. But then you’re also talking about a machine that could suck up a vacuum cleaner from across the room and turn it into a lethal projectile. A proper degausser will be a lot weaker than an MRI machine.
But outside of those, no magnet that you can hold in your hand will demagnetize a modern hard drive at any distance outside of the case, because there are magnets inside the case that are stronger than you can hold in your hands, and they’re used to move the head/arm assembly at mind-blowing speeds — and accuracy.
I have some old Imprimis Wren VII hard drive magnets still on my dad’s fridge, from the time when I did an internship there in 1989. I won’t say that you can’t remove them from the fridge, but they are stuck on there extremely well, and there are a number of people who had been injured by having their hand or fingers caught between those magnets and a ferrous metal object — like a fridge.
And that was 1989. The magnets they use now are much stronger.
Now, if you happened to put a hard drive inside an MRI machine, that would do the job. But then you’re also talking about a machine that could suck up a vacuum cleaner from across the room and turn it into a lethal projectile. A proper degausser will be a lot weaker than an MRI machine.