I was reading somewhere that secure HDD erasing programs erase all disk sectors multiple times with a random sequence of bytes.
My question is: logic tells me that surely doing it once to every single sector (including those marked bad by the HDD) is enough?
If it weren't enough then we should be concerned about the ability of the HDD to reliably write/retrieve data in the first place.
To me it sounds like some bureaucrat without any real knowledge deciding that it would be a good idea.
Am I missing something?
EDIT: I'd like to add the following link that seems to support my argument. http://hostjury.com/blog/view/195/the-great-zero-challenge-remains-unaccepted