To erase magnetic media, we need to overwrite it many times with alternating patterns in order to expose it to a magnetic field oscillating fast enough that it does the desired flipping of the magnetic domains in a reasonable amount of time. Using our knowledge of how the data is encoded, we have chosen which decoded data patterns to write in order to obtain the desired encoded signal and reorient it effectively, thus rendering it meaningless.
Date added 28 May 2012
Last Updated 12 Oct 2012
