ABSTRACT
In 1956, IBM built the RAMAC, the first magnetic hard disk drive, featuring a total storage capacity of 5 MB at a recording density of 2 kbit/in.2 (Moser et al. 2002). The invention of the hard disk drive forever changed information storage, and major research and development has since been concentrated in the area of improving the recording density in hard disk drives. As a result of this mammoth effort, the areal density (number of bits/area) of recording media has increased exponentially for more than 50 years. The annual increase of the storage density has consistently been greater than 25%, at times even outpacing Moore’s law with areal density increases of 100% per year in the 1990s (Richter 2009). Even the projected limit of density storage has grown exponentially over time, probably because engineering feats have overcome perceived obstacles in the design of recording media.
