Seagate Technology Holdings plc today debuted Mozaic 3+, a new hard drive architecture that features a so-called nanophotonic laser for writing data and several other hardware innovations. 

The company will use Mozaic 3+ to power its flagship Exos line of data center HDDs. According to Seagate, the new hard drives it’s bringing to market will be capable of storing more than 30 terabytes of information. That’s nearly twice the capacity offered by the average data center HDD, which can hold only about 16 terabytes’ worth of files.

HAMR-powered hard drives

Mozaic 3+ is based on a technology known as HAMR, or heat-assisted magnetic recording. The technology increases HDDs’ capacity by addressing some of the technical limitations that historically constrained disk storage.

A typical data center HDD contains multiple compact, magnetic discs known as platters. Each platter holds numerous microscopic structures called grains. HHDs store data by encoding bits into those structures’ magnetic fields. The so-called direction of a grain’s magnetic field determines whether it represents a one or a zero.

One way storage makers such as Seagate increase their hard drives’ capacity is by adding more grains. Because of space constraints, that necessarily requires packing grains more densely on an HDD’s platters. This increased density, in turn, gives rise to certain technical challenges.

When grains are located in close proximity to one another, they interfere with each other’s magnetic fields. This interference mixes up the data encoded into their magnetic fields. The result is decreased HDD reliability, which is a particularly major issue in data centers hosting mission-critical business information.

The HAMR technology on which Seagate’s new Mozaic 3+ hard drive architecture is based addresses the issue. In a HAMR-based HDD, grains are made of materials that only change their magnetic direction at relatively high temperatures. At room temperature, a grain’s magnetic field can’t be modified by interference from its neighbors, which reduces the risk of data loss. 

By mitigating the reliability issues associated with magnetic interference, HAMR allows storage makers to make higher-capacity hard drives than they could before. But that increased capacity comes at a cost. Because HAMR grains can change their magnetic direction only at high temperatures, they have to be heated up before new data can be written. Seagate’s hard drives accomplish that task using tiny laser emitters included in their case.

New hardware features

Seagate says Mozaic 3+ has an edge over other HAMR implementations. According to the company, the current iteration of the architecture makes it possible to store more than 3 terabytes of data in each of a hard drive’s platters. Seagate expects that number to reach more than 5 terabytes in the coming years as its engineers refine the technology. 

“Seagate is the world’s only hard drive manufacturer with the areal density capability to get to 3 TB per platter and with 5 TB on the horizon,” said Seagate Chief Executive Dave Mosley. “As AI use cases put a premium on raw data sets, more companies are going to need to store all the data they can. To accommodate the resulting masses of data, areal density matters more than ever.”

One of the main highlights in Mozaic 3+ is its grain design, which is based on an alloy that Seagate describes as an “iron-platinum superlattice.” A superlattice is a microscopic structure comprising different materials that are stacked atop one another in layers. According to Seagate, the alloy makes Mozaic 3+ hard drives’ grains less susceptible to magnetic interference, which should reduce the risk of data loss and make it easier to boost future HDDs’ capacity.

The new HDDs also feature what the company describes as a nanophotonic laser emitter. This component is responsible for heating up a hard drive platter’s grains to the temperatures at which writing new data becomes possible. The emitter shines laser light on only a tiny section of a platter’s surface area, described as an “infinitesimal heat spot” by Seagate, to optimize data write reliability.

HDDs require the ability to not only ingest new information but also make the files they already store available for applications. Mozaic 3+ accomplishes the latter task using a so-called spintronic reader that can extract the data encoded in grains’ magnetic fields. According to Seagate, the component is one of the smallest and most sensitive sensors of its kind in the industry. 

The company designed a new embedded processor to coordinate the flow of data in and out of Mozaic 3+ hard drives. It’s a system-on-chip, a processor that combines several different compute modules in a single piece of silicon. Seagate says that the chip provides up to three times the performance of earlier microcontrollers in the category.

The company detailed that the architecture will power several new additions to its flagship Exos line of data center HDDs. The upcoming hard drives, which will enter mass production later this quarter, are set to offer capacities of 30 terabytes and above. The company says that one “leading cloud service provider” has already decided to upgrade most of its existing Seagate hard drives to Mozaic 3+ hardware. 

Photo: Wikimedia