US researchers say new technology has produced an improved optical disc, five to10 of which could hold the entire print collection of the Library of Congress. The discs, which can hold between 1 to 2 terabytes of data -- equivalent of 1,000 to 2,000 copies of the Encyclopedia Britannica -- would provide small- and medium-sized businesses an alternative to storing data on energy-wasting magnetic disks or cumbersome magnetic tapes, researchers at Case Western University in Cleveland said. The new disks write data in dozens of layers, not the two to four layers found in standard Blu-ray discs, they said. \"A disc will be on the capacity scale of magnetic tapes used for archival data storage,\" Kenneth Singer, Case Western physics professor, said. \"But, they\'ll be substantially cheaper and have one advantage: you can access data faster. You just pop the disc in your computer and you can find the data in seconds. Tapes can take minutes to wind through to locate particular data.\" Only slight adjustments to a standard disc reader would enable it to probe and read the data on the multiple layers of the news discs, the researchers said. The discs are being pitched as a way to store data that isn\'t needed instantaneously or often, but is valuable enough to keep around, they said.