The Nobel Prize in Physics 2007 went to two scientists who discovered the nanoscale physics phenomena that enables data to be so densely packed onto hard disks, enabling, for example, iPods to have increasingly larger storage capacities. In 1988, Albert Fert of the Université Paris-Sud and Peter Grünberg, of Forschungszentrum Jülich, independently discovered giant magnetoresistance (GMR), how weak changes to a magnetic field can be detected as major fluctuations in the system's electrical field. From the Nobel Prize Web site:
A hard disk stores information, such as music, in the form of microscopically small areas magnetized in different directions. The information is retrieved by a read-out head that scans the disk and registers the magnetic changes. The smaller and more compact the hard disk, the smaller and weaker the individual magnetic areas. More sensitive read-out heads are therefore required if information has to be packed more densely on a hard disk. A read-out head based on the GMR effect can convert very small magnetic changes into differences in electrical resistance and there-fore into changes in the current emitted by the read-out head. The current is the signal from the read-out head and its different strengths represent ones and zeros.
Link to Fert and Grünberg's Nobel Laureate page, Link to Associated Press article
