We’re still a long way from actually having this technology deployed, but IBM researchers have made a major advance in magnetic tape density that should keep the spindles spinning for many years to come. Working with FUJIFILM Corporation of Japan, the scientists at IBM Research – Zurich recorded data onto an advanced prototype tape, at a density of 29.5 billion bits per square inch — about 39 times the areal data density of today’s most popular industry-standard magnetic tape product.
"The real highlight of the announcement is the areal density we were able to show," says Mark Lantz, research staff member, tape storage research at IBM Zurich. This means customers could get 44 times the storage capacity in the same form factor as today’s current tape cartridges. "It shows how much potential tape has to continue to scale to higher capacities and hence lower costs per gigabyte in the future."
Tape has been around for almost 60 years, going back to the IBM 726 Magnetic Tape Unit, which used reels of half-inch-wide tape that each had a capacity of about 2 megabytes. This week’s announcement represents a potential increase in capacity of 17,500,000 times compared with the 726.
The breakthrough involves several new technologies that are estimated to enable cartridge capacities that could hold up to 35 terabytes of uncompressed data, about 44 times the capacity of IBM’s current LTO Generation 4 cartridge. According to IBM, this demonstration represents a step towards achieving recording densities of 100 billion bits per square inch and beyond.
IBM researchers have dramatically improved the precision of controlling the position of the read-write heads during the past few years, leading to a more than 25-fold increase in the number of tracks that can be squeezed onto the half-inch-wide tape. They have also developed new detection methods to improve the accuracy of reading the tiny magnetic bits, achieving an increase in the linear recording density of more than 50 percent. A third enabling technology was a new, low-friction read-write head.
The bottom line is that tape has a very sustainable path to the future, says Lantz. "Despite storage vendors who don’t sell tape and say tape is dead… tape is not only alive and well but has a really bright future to come."
While these numbers are approximations, Lantz says tape typically costs a 10th of disk drives, which cost a 10th of flash storage. "These technologies have historically scaled at fairly similar rates, although recently flash has scaled faster than HDDs so their prices have fallen more." He adds that both flash and disk-based technologies will face some very difficult challenges in the future to maintain those rates of scales.
Another critical factor in tape’s favor is energy consumption, says Lantz. Disk typically consumes 200-300x more energy than tape. While disks must be constantly spinning — and consuming energy — tape libraries have relatively few active drives, and the tapes themselves consume no energy. With energy accounting for up to half of storage costs, that’s a huge concern in data centers that are running out of space and power. "Tape is by far the greenest source of technology today."