Ubuntu – Possibility of recovering files from a dd zero-filled hard disk


I have "zero filled" (complete wiped) an external hard disk using dd, and from what I have heard: people said you should at least "zero fill" 3 times to be sure that the data are really wiped and no one can recover anything.

So I decided to scan the disk once again after I've zero filled the disk. I was expecting the disk to still have some random binary left. It turned out that it has only a few sequential bytes in the very beginning. This is probably the file structure type and other headers stuff. Other than that, it's all zeros and nothing else.

So if we have to recover any file from a zero filled disk, …how? From what I've heard, even you zero fill the disk, you should still have some data left. …or could dd really completely annihilate all data?

Best Answer

As you can read here, it is impossible to recover data after you "zero filled" it.

There can be a chance of 56% to recover a single bit correctly, but since you had to recover 8bit to get only one byte, it is very unlikely to recover any data.

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