Magnetic storage uses an arrangement of magnetic impressions on a disk or tape, while optical storage uses pits in the surface of a material. Of the two, optical data storage is far more durable for a number of reasons.
Physical Differences
The pits in the surface of an optical storage disk, such as a CD or DVD, are far less susceptible to physical damage or degradation than the matrix of ferrous particles in a magnetic storage tape or disk. In addition to this, optical storage disks need not be kept in tightly sealed containers as they are not susceptible to contaminants such as fingerprints or dust.
