The amount of new information stored on various media such as hard drives has doubled in the past three years, to five exabytes of new information produced in 2002, according to a study released Tuesday by the University of California, Berkeley. That's exabytes, as in one byte with 18 zeros behind it, six zeros more than a terabyte. The amount of information put into storage in 2002, five exabytes, was equal to the contents of a half a million new libraries, each containing a digitized version of the print collection of the entire U.S. Library of Congress, according to the study by professors Peter Lyman and Hal Varian of the UC Berkeley School of Information Management and Systems. The professors estimated that between two and three exabytes of information was generated in 1999. Most of that data -- 92% of it -- was stored on magnetic media, primarily hard drives, the study estimates.