Magnetic hard disks will soon be able to store one terabit (a trillion bits) per square inch. Seagate has demonstrated that landmark storage density using a new magnetic recording method that can cram 10 terabits, and perhaps even more, onto every inch of a standard 3.5-inch disk. Disks made with current technology can hold about 3 terabytes.
The technology, called heat-assisted magnetic recording, involves heating the magnetic regions on a disk that hold individual data bits, allowing those regions to be made tinier. Seagate says the method promises to keep increasing storage density, and it could lead to 60-terabyte hard drives.
"One of the most exciting things about heat-assisted magnetic recording is that it's in its infancy," says Ed Gage, principal technologist of heads and media R&D at Seagate. The company is targeting 2015 for its first commercial product featuring the technology.
Today's hard disks are made of magnetic cobalt-platinum alloys. Each bit is stored on a tiny area with a magnetic field pointing in one of two opposite directions, denoting a binary digit 1 or 0. The smaller these magnetized areas are, the higher the density of the disk. When the areas get down to 25 nanometers to a square side (corresponding to 1 terabit per square inch), they become unstable, meaning that a small amount of heat can make them flip their magnetic field direction.