Urban legends

You really need a big ass magnet to do any harm to the data on current hard drives. The data on current hard drives is so dense by now, that it is compleatly enough to overwrite the whole disk with some garbage data and _NO_ software can retrieve them afterwords. There may only be some sectors on the disk that you do not reach by software, to overwrite, because they got hidden due to a error correction or some internal logic of the disk. But if you could not reach them to write data to, then another person will not be able to read them either, not without real indeep knowledge of at least the ATA protocol. ^^