In 1959 Richard Feynman said that all the information accumulated in all the books in the world could theoretically fit in a cube 1/200th of an inch on a side. Looks like he got it right.

Technology Research News is reporting that researchers from the University of Wisconsin at Madison have put the theoretical to the test by using single silicon atoms to represent the 1s and 0s of computing. This is equivalent to storing the contents of 7,800 DVDs in one square inch of material.