Dual-layer magnetic tape, also known as dual-side magnetic tape, is a high-density storage medium with a capacity more than 15 times that of conventional magnetic tape. IBM and Fuji Photo have developed a prototype system that stores 6.67 billion bits of data per square inch.
According to IBM, dual-layer magnetic tape in a linear tape open (LTO) cartridge could store the same amount of data as eight million books, in a format half the size of a single VHS cassette. The prototype uses dual layers of barium ferrite, which is stable over time and not prone to corrosion, to provide greater data longevity and better read/write accuracy.
Dual-layer magnetic tape drives for consumer use are expected to be on the market by 2010.