"If you want to securely erase a hard drive, it's not as easy as writing it over with zeroes. Sure, an "erased" hard drive like this won't boot up your computer if you just plug it in again. But if the drive falls into the hands of a specialist with a scanning tunneling microscope, they can tell the difference between "this was a 0, overwritten by a 0" and "this was a 1, overwritten by a 0".
There are programs advertised to "securely erase" hard drives using many overwrites of 0s, 1s, and random data. But if you want to keep the secret on your hard drive secure against all possible future technologies that might ever be developed, then cover it with thermite and set it on fire. It's the only way to be sure."
There have been no cases of anyone ever restoring a zeroed hard drive. It's utter bullshit. Especially these days with our precision aligned platters and insane densities.
between the quote below from the article and the excellent picture above, you should be able to see it....Try again, cuz it's really interesting.
"Imagine you're driving on a circular race track. You overtake a car on the right, and immediately slow down and go into the left lane. When the other car passes you, you speed up and overtake on the right again. You will then be making circles around the other car, but when seen from above, both of you are driving forward all the time and your path will be convex."