Information can be stored on various computer systems and other electronic devices like portable storage media. It is important to ensure that confidential information; in particular, highly confidential and confidential data, are completely removed before disposal as files may be recovered even though they are "deleted". There are commercial service providers who could recover data from damaged hard disks. To minimize the risk of information leakage, extra steps to permanently remove/wipe out the data should be taken before disposing storage media holding highly confidential or confidential data.

There are basically 3 kinds of storage media and different types of storage media require different methods of wiping. The following are some examples:

  • Optical: CD /DVD discs => physical destruction
  • Magnetic: Zip disks, floppy diskettes, hard disk drive, magnetic tapes => overwriting or degaussing
  • Electronic: USB Flash drives and memory cards => overwriting

How should I remove data on different types of storage media?In order to securely and permanently remove data from a device, various methods are used on different types of storage media.

  • Overwriting (Wiping) - Overwriting is an approved method for removal of data on electronic or magnetic storage media. Overwriting of data means replacing previously stored data on a drive or disk with a predetermined pattern of meaningless information. This effectively renders the data unrecoverable, but the process must be correctly understood and carefully implemented.
  • Degaussing (for magnetic storage media only) – A process whereby the magnetic media are erased with strong magnetic field. It is a proven method to permanently wipe out the data on magnetic media. However, the magnetic field may destroy the magnets in the motors and markings, rendering the degaussed media dead for good.
  • Physical destruction – Physical destruction is recommended for media that cannot be wiped nor degaussed, such as CD-ROMs, broken disk drives, DVDs, tapes, or other damaged media devices.

For more information on the use of degausser available at OCIO, please kindly contact IT Help Desk.