Seagate today announced upgrades to its 2.5-in. laptop hybrid drives and released its first 3.5-in. desktop hybrid drive.
Hybrid drives combine a relatively small amount of NAND flash with traditional spinning disks along with firmware that determines where data resides on the disk based on application performance requirements.
Because the hybrid drives use spinning disk, they can provide terabyte-plus capacities, but because of the NAND flash, they can offer performance similar to solid-state drives (SSDs) with price points approaching traditional hard disk drives.
As part of today's release, Seagate also announced it will no longer sell its hybrid drives under the Momentus XT name and will now use the brand SSHD (solid-state hybrid drives) to better reflect the technology.
Seagate's SSHD hybrid drive family.
The drives represent Seagate's third generation of 2.5-in. hybrid drives. The release includes a new version of its standard laptop hybrid drive and 7mm-high "Thin" SSHD, designed to fit smaller laptops, such as ultrathin notebooks.
One notable change to the 2.5-in. line is that Seagate is now using 5400 rpm spinning disk, versus the 7200 rpm spindles of its previous generation drives. But, even with the slower spindle speeds, the new Seagate Laptop and Laptop Thin SSHDs boast performance that's as much as 40% faster than previous generations, and can add as much as 30% to total system performance -- regardless of the processor inside the system, according to David Burks, Seagate's director of global marketing.
To boost performance in the slower spindle speed drives, Seagate deployed a new NAND flash subsystem, using upgraded write caching algorithms that automatically write all high-priority data directly to flash. In past generations, all data was initially written to spinning disk and then migrated to flash as performance metrics required, Burks said.
"[The firmware] constantly monitors every block of data and evaluates it as to whether it's boot information or data frequently used by the operating system or an application. At the same time, we also evaluate the data based on what its impact is on system performance if it's stored on hard disks versus the SSD portion of the drive," Burks said.
For example, Burks said, if the data consists of long, sequential blocks, there is no benefit in storing it on the NAND flash, whereas random data consisting of short -- 4KB and 8KB -- blocks can benefit from the low search latency of the solid-state memory.
The new Seagate Laptop and Laptop Thin SSHDs come with 8GB of NAND flash. The drives come in single-platter 500GB or dual-platter 1TB capacities.
Burks said Seagate is working with Intel, which created the specifications for ultrabooks, in order to get their hybrid drives into more models of the ultrathin laptops. Currently, some ultrabooks contain separate NAND flash and hard disk drives in order to achieve Intel's low threshholds for fast boot-up and data sleep-to-active-mode times.
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