Shingled Magnetic Recording: Seagate develops 5 TB disks with SMR

3.5-inch disks are currently delivered up to a maximum of 4 TB. Now Seagate has announced that it will deliver 5 TB TBDs next year. By 2020, HDDs with 20 TB are planned. The capacity increase is made possible by a new recording technique called SMR (Shingled Magnetic Recording). In this technique, the individual magnetized zones are stacked one on top of the other in a shingle-like manner.


Up to now, increases in the recording density, in addition to the improvement of materials and mechanics, have been achieved mainly by narrower traces. The storage densities achieved have been quite astonishing. They reach about 700 gigabits per square-inch (quadratzoll, just over 100 gigabits / cm²). The tracks are only 75 nanometers wide and one bit is only about one nanometer long on this track. These values ​​have been valid since about 2010, for physical reasons that seemed to be unstable.


Seagate has now superimposed the magnetic traces so far that they overlap like roof shingles. Since the read heads can be made smaller than the write heads, the data can nevertheless be read out. The process is initially only to be used for 3.5-inch plates, whether it should also be transferred to 2.5-inch, left Seagate as open as the expected prices.