For an actual HDD, maybe that would work. For any solid state drive, it would definitely not work. SSDs and similar spread writes across pools of blocks for 'endurance', so a 1TB drive might actually have 2TB worth of flash on it.
>so a 1TB drive might actually have 2TB worth of flash on it.
That's overly optimistic
It doesn't work as well as you'd think on spinning platters, either. Although it does increase the amount of effort needed to read the data on them.
With the proper equipment and expertise (and helped out by the error correction mechanisms), you can recover a substantial amount of data that has been "overwritten" on an existing track.
This is why "data shredding" applications erase the old data by overwriting it with random data multiple times. That increases the chances that one of those writes will also write over any older data that was shifted slightly to the side.
But that's no guarantee. This problem is why organizations that need an extreme level of security require the complete physical destruction of the platters when decommissioning.
I wasn't, exactly, but I also wasn't correct in the modern day. Retrieving erased information from hard drives like this was certainly a thing (a thing that I myself have seen done, so I know first-hand).
However, after hard drives moved beyond MFM it stopped really being possible.
So what I was saying isn't wrong, exactly, but certainly isn't relevant to today's hardware.
Hard disks don't record zeros and ones...
It's an extremely difficult problem, and in the best case you won't get a complete copy of old data. That's why this isn't an avenue of attack that you're likely to ever encounter.
This is the sort of thing that would only be considered by very wealthy attackers (governments and corporations), and even then only if they're very certain that the drive contains data of unusually high value.
But it is possible, and has been done, to extract useful data that has been overwritten a single time with zeros.
It's not possible, because there's no way to distinguish what the previous value was.