PORTLAND, Ore. — The only memory medium keeping up with Moore's Law, according to IBM, is magnetic tape. And you thought the 60-plus-year-old magnetic tape was old school.
Today IBM and FujiFilm proved the point by reporting a 62-fold increase in the amount of data that can be stored on a standard Linear Tape-Open (LTO) cartridge -- 154 terabytes, versus just 2.5 terabytes in the 2012-vintage LTO.
IBM's demonstration showed that FujiFilm double-coated tape could store 85.9 gigabits per square inch -- a world record in areal density for low-cost linear magnetic particulate tape. The increase in storage density allowed an IBM customer to downsize its video archive from 1,507 to just 388 square feet.
"Today, most storage technologies like HDD [hard-disk drive], flash, and DRAM [dynamic random access memory] are facing or will very soon face very difficult challenges to continue scaling. In contrast, our demonstration shows that tape can continue scaling at the current rate of doubling cartridge capacity every two years for at least the next 10 years," Mark Lantz, a research scientist and manager of exploratory tape at IBM Research, told us.
IBM's record-holding tape drive uses a giant magnetoresistance (GNR) read head with a gap of just 90 nanometers.
It is also important to note that this demonstration does not represent any kind of physical limitation on the scaling of tape, but rather is a snapshot of the state of the art of the technology today. We are currently working on continuing to push the limits of tape technology to higher areal density and believe that particulate media will scale to 100+ gigabits per square inch. Beyond this, sputtered media will likely allow the continued scaling of areal density.
The FujiFilm tape deposited an undercoat directly on top of the substrate or base film, and then a thin 70-nm magnetic recording layer of the next-generation version of the NanoCubic formulation that uses a ultra-fine, perpendicularly-oriented barium-ferrite (BaFe) magnetic medium on top of the undercoat. As a result, IBM's stronger write heads could increase the linear recording density by more than 56% and increase track density 27-fold.
"The new write head technology consists of Ni45Fe55 [nickel iron] write poles with an additional 200-nm layer that contains a mixture of iron and cobalt, deposited between the write gap and the trailing edge pole," Lantz said. "This extra 200-nm layer is made from a material with a much higher saturation flux density than the Ni45Fe55 used in standard tape heads. This layer guides the magnetic flux to the write gap and results in much larger write fields enabling the use of our higher coercivity media."
The new record in areal data density on low-cost linear magnetic particulate tape is 85.9 billion bits per square inch.
The new 90-nm-wide GMR read head enabled a linear density of 600,000 bits per inch and the use of a track width of just 177 nm with track-following performance within 10.3-nm standard deviation from the target track position.
"H-infinity was our design methodology for a control system that allows one to take into account the properties of the system such as the speed or bandwidth of the actuator, the amount of delay in the control loop, the nature of the noise in the system, and the type of disturbance and then optimize the controller design using weighting functions," he said. "But it is important to note that it was actually the combination of the prototype servo pattern, the new servo channel, the new tape path and the H-infinity controller that enables the 10.3-nm standard deviation of the position error."
Despite tape's rosy future for the next 10 years, the medium will eventually reach the same physical limitations as HDD technology, according to Lantz. He explains the record-breaking technology in the video below.
"In regards to alternative technologies to tape, at the moment there are no emerging technologies -- at least none of which we are aware -- that can compete with tape in terms of its combination of very low cost per GB, high data rate, and future scaling potential," he said. "We are actively looking for alternatives but so far have not found any. But we have at least another 10 years to find something."
All the details will be presented at the Magnetic Recording Conference Aug. 11-13 in Berkeley, Calif.
— R. Colin Johnson, Advanced Technology Editor, EE Times