- Magnetic tapes, floppies and harddisks can have the recorded signal/data damaged by metal detectors and any other magnetic field that´s strong enough (loudspeakers, motors, power supplies...). Also, excessive temperatures can damage the mechanical carrier material and can degrade the magnetic recording.
-R(W) / DVD-R(W) / DVD+R(W) / MiniDisk (recordable optical disks): Cannot
be damaged by magnetic fields as the recording is done by causing phase changes
in the data-carrying layer in the disks. This layer can, however, be damaged by heat and by excessive light exposure. Also, the carrier plastic can warp in heat and make the disk unplayable.
/ DVD: Only damageable by heat or extreme violence (scratches, aggressive chemicals, manufacturing defects), since the data-carrying layers consist of metal and are very stable.