Technofile : In the groove

By embossing grooves onto a CD instead of etching them, two American
electrical engineers say they can squeeze up to 65 gigabits of data onto each
square centimetre of disc. Stephen Chou and Peter Krauss have been able to make
the grooves only 10 nanometres across—too fine for the lasers that read
conventional CDs. Reading the data requires an atomic force microscope, which
Chou and Krauss are now trying to fit onto a single chip.