HAMR: unlocking the next stage of data growth

Editorial Type: Technology Focus Date: 01-2019 Views: 876 Tags: Storage, HDD, Strategy, Data Centre, Hard Drives, Seagate PDF Version:
Jason Feist, Managing Technologist at Seagate Technology, describes how a laser no bigger than a grain of salt is just one crucial element of the next generation of hard drive technologies
One thing is for sure: the conventional way we store data is reaching its limit. For the past few decades we've grown accustomed to hard drive capacity increasing as surely as the passing of the seasons. But this will soon change.

The world is producing more and more data. With the development of technologies like machine learning, 5G and AI this statement might not come as a surprise, but the sheer scale of the challenge ahead is worth remembering. By 2025 the 'global datasphere' is expected to reach an astounding 175ZB, according to research from IDC sponsored by Seagate. Nearly half (49%) of that data will reside in the public cloud, further highlighting the urgent need for new technology to help deal with this massive increase in the production and storage of data at scale.

Seagate is a company with a 40-year heritage in data storage and management. We understand these global industry trends, which is why we have invested our considerable research & development resources behind a technology called heat-assisted magnetic recording, or HAMR for short. With HAMR, hard drive capacities of 20TB and more will become commercially available from 2020, and the technology has the potential to make capacities of 100TB or more a possibility within a few decades. The first HAMR drives are already out with Seagate customers for final testing and have been receiving excellent feedback. Here's the story of why we need a rethink of how we store data, and how we're charting a way forward with HAMR technology.

While easily integrated and totally transparent to the end-user, HAMR is a highly complex technology sorely needed in the data storage industry in order to maximise capacity offerings. In order to appreciate why HAMR is so important, we first need to understand the current state of data storage technology and why we need innovative technologies in order to be sustainable. The vast majority of hard drives in the world today use technology called conventional magnetic recording (CMR). These hard drives are made up of disk-shaped platters, covered in a thin film of recording medium. This recording medium is made up of tightly-packed grains, which are polarized by magnetic fields produced by a write head in such a way that they can later be read as either '0' or '1'.

Around a dozen of these grains make up a single bit of data, and the key to boosting the capacity of our hard drives has been developing new ways to make the grains smaller and pack as many as possible in a given space. This strategy has served the industry well for a number of years, but we're reaching the end of its usefulness. At a certain point, the grains on a storage medium are so small that they become unstable, potentially flipping between 0 and 1 when they're not supposed to. This can lead to data corruption and is clearly not acceptable; we need another solution if we are going to maintain a steady increase in hard drive capacity and keep up with the rapid growth in data storage needs projected over the coming years.

HAMR is a technology developed by Seagate that enables a significant increase in the amount of data that can be stored in a disk. Put simply, HAMR allows us to continue to shrink the size of the grains which makes it possible to increase areal density more than in previous types of hard drive.

At the outset we knew that in order to reduce the grain size , we would need to experiment with the materials used to create the recording media. We tested a few different options, primarily high-anisotropy (or "hard") magnetic materials such as iron-platinum alloys (FePt). The challenge with these materials is that, while they allow more bits to be recorded within a smaller space, these bits cannot be flipped under the normal temperatures that conventional hard disks operate at. In order to write data to drives with FePt recording media, the media needs to be hotter at the time of recording.

The theory behind HAMR technology is deceptively simple. In order to record data to the medium, it must first be heated up, to over 400°C. A tiny portion of the recording medium is brought to this temperature for a very short time - around one nanosecond - which allows the data to be recorded reliably and then 'frozen' in place once the temperature has decreased. Seagate has tested approximately 40,000 HAMR drives so far, and the technology will be commercially ready very soon. Crucially, the new technology in HAMR drives has no detrimental impact on overall temperature of the hard drive or wider system, or the overall durability of the drive. For example, one of our drives has clocked up more than 4000 TB and is still going strong after an incredible 16 months of continuous HAMR writing.

Reducing the grain size in our hard drives in this way required us to completely rethink how we build our products. The structure of existing hard drives using conventional perpendicular magnetic recording heads designed to operate at room temperature would simply not work.

HAMR is an amazing combination of technologies incubated by Seagate. We have designed an entirely new recording head which incorporates a tiny laser, no bigger than a grain of salt, which is capable of heating the recording media to the right temperature. We needed to introduce a host of other new components to HAMR drives to get them operating effectively, such as optical waveguides and near-field transducers, as well as tackling the thousands of small issues that engineers encounter whenever developing a new product.

Seagate is committed to making the most out of emerging technologies and their potential for improving customers' ability to store and use their data effectively, and HAMR technology is just the latest example of this. Back in 2014 we introduced shingled magnetic recording, which increased areal density by 10%, and the following year we developed helium-sealed drive technology, enabling drives to run with more disks while using less power.

With today's HAMR technology we're currently on track to deliver five terabits per square inch, an unimaginable milestone just a few years ago. Keeping up with the constantly growing amount of data generated by the public and by businesses around the world is a challenge we work to solve every day.

HAMR is going to deliver tangible storage improvements years into the future. According to our estimates, HAMR technology will enable us to achieve a 30% compound annual growth rate (CAGR) in disk drive capacity over the next 10 years. HAMR drives are just the beginning: the world's storage needs are increasing rapidly, and HAMR is the latest step in a long heritage of innovative systems and ideas to store the world's data.
More info: www.seagate.com

"The theory behind HAMR technology is deceptively simple. In order to record data to the medium, it must first be heated up, to over 400°C. A tiny portion of the recording medium is brought to this temperature for a very short time - around one nanosecond - which allows the data to be recorded reliably and then 'frozen' in place once the temperature has decreased."