[ILUG] wiping a faulty hard disk

[pat oleary]

Hi folks,
         I have a few faulty hard disks which i need to return to the
supplier for under guarantee replacement. The problem is that they
have an OS installed on them along with some sensitive data. My boss
wants all the data erased before we return them. The only way i could
think of erasing them was to run them through a large & powerful video
tape eraser. I found a working disk, put a few files on it & ran it
through the eraser, but to my surprise it came out the other side with
the files still perfectly readable. Any help or suggestions would be
greatly appreciated on this one. BTW, i considered drilling a few
holes in the disk itself, but the suppliers may not honour the
guarantee then?

TIA,

Pat