One of the joys of old science fiction movies is watching the giant reel-to-reel tape drives spin around as they serve computers less powerful than a modern wristwatch. But magnetic tape isn't just something found in old UFO episodes; it’s a key component in modern digital systems required to keep modern online systems reliable. At the INTERMAG Europe 2014 international magnetics conference in Dresden, Sony announced a new breakthrough in magnetic tape technology that keeps the medium relevant by allowing a tape cartridge to carry 74 times the data of a conventional data tape, or the equivalent of 3,700 Blu-ray discs.
Tapes were the backbone of computer memory storage from the 1950s until the late 1980s. They're familiar to early home computer users in the form of the humble audio cassette that saved them from having to laboriously type in a program every time they wanted to run it. In everyday life, tapes were replaced so universally by hard discs, flash drives and optical media including CDs, DVDs and Blu-rays that it often comes as a surprise to learn that magnetic tape is still widely used as back up memory for servers and databases. Because, while discs may be fast and flexible, tape still has the advantage of being very stable and using much less power than hard disc drives, so tape is anything but yesterday’s technology.
Sony’s breakthrough, which pushes past the previous record set in 2010 by a factor of five, produces a recording density of 146 Gb per square inch. This results in a cartridge capable of holding 185 TB. Conventional tapes fall well short of this by comparison with a density of 2 Gb per square inch and a maximum capacity of 2.5 TB.
To achieve this density, Sony uses a new “sputter” technique to deposit fine nano-grain magnetic particles on a soft polymer underlayer less than 5 micrometers thick. These particles are much smaller than those found in conventional tapes, which are tens of nanometers wide. The fineness of the particles already improves the storage capacity of the material, but the tricky bit was getting particles to line up in an orderly fashion instead of landing at random on the underlayer.
This uniformity was achieved by using an electrostatic discharge to force argon ions into the target material, which forms it into a thin, uniform layer. It involves having the magnetic particles of both the same average size (about 7.7 nanometers) and lined up in the same direction. In addition, the polymer underlayer has been re-engineered to make it much smoother, so the particles lie more evenly. The result is a tape material that Sony boasts has the world's highest recording density by area.
Sony says that it is currently working on commercializing the new tape material, as well as improving the sputter technique to achieve even greater recording densities.