Heat-assisted magnetic recording (HMAR) has been touted as the next great technology for increasing hard drive capacities without reducing other key performance metrics. How does HAMR work — and does it offer clear advantages over current tech?
First, a quick look at the problem: Hard drives have increased in capacity for the past 70 years, but at a certain point, massive increases in areal density (the amount of data storage per given unit of physical space) requires massive advances in engineering.
That’s because hard drives store data on disks (called platters) with magnetic charges. Even with advances in platter construction, a hard drive’s read/write heads can only fit a certain number of magnetic charges into a given amount of space without sacrificing reliability.
However, the math changes if the read/write heads use new methodologies when writing data. One potential option: Heat up the platters. Temporary application of heat can make platter materials more receptive, potentially enabling them to receive more bits of data per region.
In layman’s terms, heat-assisted magnetic recording applies heat to hard drive platters, allowing magnets to do their work more effectively. But how will the technology change hard drive form factors — and why is it necessary?
How HAMR Hard Drives Work
Conventional hard drives are limited by superparamagnetism, a physical limit to the size of the magnetic particles used to record data. Essentially, when ferromagnetic particles get small enough, they can randomly flip direction — which makes them too unstable for data storage.
Heat-assisted magnetic recording uses a standard hard drive form factor, but with an additional heating component attached to the read/write head assembly. Essentially, HAMR drives are normal hard drives with a laser diode attached.
The laser diode targets a tiny spot on the platters, providing enough heat to allow the heads to flip the magnetic polarity of each bit. This makes data easier to write. As the platters cool down — a process that occurs almost instantaneously — the bits are “locked” into place, ensuring the reliability of the hard drive.
White papers from Seagate and other manufacturers show that the process is stable and capable of providing an areal density of 2 terabytes per square inch (2 Tbpsi). That’s a significant improvement over conventional technologies and could allow for hard drive capacities of 80TB or more over the next decade.
Heat-Assisted Magnetic Recording: Challenges and Benefits
Modern consumer hard drives can store terabytes of data, which is certainly sufficient for the average computer user. With more data moving to the cloud, most personal computer users don’t need higher capacities from their physical storage media.
But higher capacity hard drives have enormous benefits for server applications. In order to be appropriate for a server or other large-scale storage device, HAMR hard drives will need to meet several criteria:
- HAMR drives need to match current hard drive form factors. Otherwise, buyers would need to upgrade their equipment to use the new tech — which would defeat the purpose.
- HAMR drives need to be reliable. While RAID arrays offer redundancy, the cost of replacing hard drives can be considerable; HAMR drives need to offer the same reliability as conventional enterprise-grade hard drives.
- HAMR drives need to be affordable. The cost per gigabyte needs to be aligned with current market expectations.
Based on research released by major manufacturers, the first generation of HAMR hard disk drives will meet all of these requirements.
Will consumer-grade HAMR drives become available in the near future?
Probably not immediately. As discussed above, HAMR technology is intended for enterprises that create, manage, and transfer tremendous amounts of data. For these organizations, speed is less important than capacity, since the overall speed of the server isn’t limited by the speed of any individual storage device.
Few consumers are interested in attaining the lowest possible cost-per-terabyte — particularly when HAMR drive capacities start at around 20 terabytes and cost upwards of $700. For most applications, conventional hard drives and solid-state drives offer plenty of storage space at a much lower price.
Is data recovery possible on HAMR hard drives?
HAMR hard drives present unique challenges for data recovery engineers. However, while the chances of data corruption can increase with a higher areal density, the diodes of HAMR drives do not significantly decrease the chances of a successful data recovery attempt. Of course, most (if not all) HAMR drives are installed in servers, and data recovery engineers need an advanced working knowledge of RAID functionality, experience with server databases, and other expertise to successfully restore data.
At Datarecovery.com, we’re investing heavily in HAMR research and development in order to maintain high success rates for the next generation of servers. To learn more, contact us at 1-800-237-4200 or click here to submit a case online.
