(Editor's Note: Min-Jie Chong, SATA technology expert at Agilent
Technologies, shares his perspective on the Serial ATA Revision 3.0 (SATA Gen 3)
standard and explains why he thinks it will be adopted quickly in server and
high-performance storage applications but slow to make inroads in mainstream
storage applications. He analyzes the threat USB 3.0 poses to the SATA Gen 3
standard and touches briefly on the challenges engineers will face when they
test their SATA Gen 3 devices. Chong concludes by discussing the importance of
digital standards and the critical role of measurement expertise in enabling
Companies are already churning out Serial ATA Revision 3.0 (SATA Gen 3)
motherboards and hard drives that run at 6 Gbits/second. But is there really a
long-term market for SATA Gen 3 products? Or will SATA Gen 3 be derailed quickly
by the almost-as-fast USB 3.0 interface that is currently taking the market by
My crystal ball is currently out of commission, but if we analyze the latest
developments in the market, we can gain clues to what the future holds.
In storage applications that use conventional, mechanical hard drives,
there's not much incentive to move from SATA Gen 2 technology, which moves data
at up to 3 Gbits/s, to SATA Gen 3, which is twice as fast. Because of the moving
parts in a rotational disk array, bandwidth is essentially capped at about 3
Gbits/s. So if you are using conventional hard drives, you don't gain much by
moving to SATA Gen 3, because the bottleneck is at the hard drive media, not the
The storage industry, however, is migrating away from mechanical hard drives
with rotational disks to solid-state drives (SSDs) with nonmoving parts.
Spinning a disk array takes a lot of power. By switching to nonmoving parts, you
reduce power consumption and increase reliability. That's important in the
server and workstation world, where data integrity is everything.
Another big reason for moving from conventional drives to solid-state drives
is the higher throughput. With SSDs, you can push throughput to 6 or even 12
Gbits/s. So moving to SATA Gen 3 makes sense for product developers who are
At about the same time the SATA Gen 3 standard was published, the Serial ATA
International Organization (SATA-IO) announced a new standard, called mini SATA
(mSATA), for an interface that operates at up to 3 Gbits/s. I believe the
published data rate is quite conservative, however, and that the SATA-IO is
being cautious with this new incarnation of the specification.
The mSATA spec eliminates the internal cable, so the host and disk drive talk
directly to each other. Compact mSATA interfaces are ideal for mobile devices
such as phones, netbooks and notebooks because they give designers flexibility
and allow them to include more memory in a smaller footprint.
Toshiba recently introduced mSATA-equipped SSDs that are about the size of a
thick business card. According to Toshiba, its 62-GB module is only one-seventh
the volume and one-eighth the weight of a standard SSD and consumes half the
power. So mSATA enables small, lightweight, reliable devices that consume less
power; sounds to me like a perfect fit for the evolving world of "mobile
In addition to Toshiba, companies such as Dell, Hewlett-Packard, Samsung and
SanDisk seem to think the technology has a future and are rumored to be working
on their own introductions.