Communications of the ACM
New Life For Magnetic Tape
IBM Research Zurich
Music lovers may have long forsaken them, but magnetic tapes still reign supreme when it comes to storing vast amounts of digital data. And new research from IBM and Fujifilm could ensure that tape remains the mass storage medium of choice for years to come for at least a decade.
At IBM's Zurich Research Laboratories in Switzerland, researchers have developed a new tape material and a novel tape-reading technology. In combination, they can store 29.5 billion bits per square inch, which translates to a cartridge capable of holding around 35 terabytes of data--more than 40 times the capacity of cartridges currently available, and several times more than a hard disk of comparable size.
The researchers used a relatively new magnetic medium, called barium ferrite. In cooperation with researchers from Fujifilm's labs in Japan, they orientated the barium ferrite magnetic particles so that their magnetic fields protrude perpendicularly from the tape, instead of lengthways. This means that more bits can be crammed into a given area, and the magnetic fields are stronger. Furthermore, these particles allow thinner tape to be used, meaning12 percent more tape can be stored on a single spooled cartridge.
Increasing the density of data that can be stored on a tape makes it more difficult to reliably read information. This is already a problem because of electromagnetic interference and because the heads themselves will retain a certain amount of residual magnetism from readings. To overcome this, the IBM group developed new signal-processing algorithms that simultaneously process data and predict the effect that electromagnetic noise will have on subsequent readings.
From Technology Review
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