Seagate has become the first hard drive maker to achieve the milestone storage density of 1 terabit (1 trillion bits) per square inch, producing a demonstration of the technology that promises to double the storage capacity of today’s hard drives upon its introduction later this decade and give rise to 3.5-inch hard drives with an extraordinary capacity of up to 60 terabytes over the 10 years that follow.
Seagate reached the landmark data density with heat-assisted magnetic recording (HAMR), the next- generation recording technology. The current hard drive technology, Perpendicular Magnetic Recording (PMR), is used to record the spectrum of digitized data – from music, photos, and video stored on home desktop and laptop PCs to business information housed in sprawling data centers – on the spinning platters inside every hard drive. PMR technology was introduced in 2006 to replace longitudinal recording, a method in place since the advent of hard drives for computer storage in 1956, and is expected to reach its capacity limit near 1 terabit per square inch in the next few years.
The maximum capacity of today’s 3.5-inch hard drives is 3 terabytes (TB), at about 620 gigabits per square inch, while 2.5-inch drives top out at 750 gigabytes (GB), or roughly 500 gigabits per square inch. The first generation of HAMR drives, at just over 1 terabit per square inch, will likely more than double these capacities – to 6TB for 3.5-inch drives and 2TB for 2.5-inch models. The technology offers a scale of capacity growth never before possible, with a theoretical areal density limit ranging from 5 to 10 terabits per square inch – 30TB to 60TB for 3.5-inch drives and 10TB to 20TB for 2.5-inch drives.
Capacity has been growing at a steady clip, but even that is threatened by the areal density limitations of perpendicular magnetic recording (PMR). It won’t pick up again until heat-assisted magnetic recording (HAMR) becomes feasible in the 2014 to 2015 timeframe.
Interfaces will continue to evolve, with 6Gb/s SAS and SATA 6Gb/s being the latest iterations. Plans exist to move to 12Gb/s SAS in the next year, but SATA is expected to stall at the 6Gb/s speeds available today.
Three years later, in May of 2010, Seagate introduced a new hybrid—the Momentus® XT drive—and coined the term solid state hybrid drive. This time the focus was on delivering the necessities of capacity, performance and price with zero disruption to the user experience. The result? Seagate Adaptive Memory™ technology allows users to experience real world system performance gains of up to 50% without third-party software or operating system dependencies. It was a hit. By August 2011, Seagate had shipped over one million Momentus XT solid state hybrid drives.
Unlike competitive technologies (such as SSD, PCIe, flash cache modules or software like Intel’s Smart Response Technology), which require differing levels of integration experience and expense for consumers and businesses alike, SSHDs look and act like traditional hard drives. There are no compatibility dynamics with operating systems, applications, or network and storage management programs. There are no physical obstacles associated with system architecture, design or expansion capability.
IBM researchers show that areal density improvements are expected to maintain a CAGR of 25% to 40% over the next few years, while the maximum sustained transfer rates of drives have begun to level off.