Days are numbered for decade-old hard drive connection tech

Switching storage connections from SATA to PCI Express means speed without hogging too much power. Marvell Semiconductor

To keep up with ever-faster electronics, the computing industry periodically rips out the old way of doing things. Today, it's hard drive maker WD's turn to do some of the ripping.

At the Computex tech show this week in Taiwan, the Western Digital subsidiary showed off a new hard drive that dumps the decade-old SATA connection technology and instead uses the faster PCI Express.

"For customers who want to discuss a future beyond vanilla SATA, WD is ready to plan the future with them," said Matt Rutledge, WD's senior vice president for storage technology, in a statement.

Consumers generally needn't fret these days about what data-transfer technology their laptop or phone uses to save files like photos or apps. That's especially the case since computing devices have shifted gradually from desktops that can be upgraded with more memory and new hard drives to sealed-chassis devices like sleek laptops and tablets. In earlier days, consumers could get caught in "bus wars" that pitted one interconnect against another and ran the risk that people would buy a component that didn't actually work in their computer.

But the shifts are important to consumers: without them, we'd be held back by last year's slower technology. SATA tops out at six gigabits per second, but PCI Express (PCIe) links run at 8Gbps each, and multiple links can be joined -- for example two PCIe lanes means a raw capacity of 16Gbps.

What's interesting about the WD shift is that it applies to hard drives -- the traditional, high-capacity storage devices made of spinning platters that store data as magnetic ones and zeros.

Moving to faster PCIe-based storage means it's time for a new connector for hard drives and SSDs. SATA-IO

Tablets and smartphones all use solid-state drives (SSDs) that instead use flash memory, which store data in chips instead for faster access, and laptops from Apple and other major PC makers have followed suit. On PCs, the first SSDs attached with SATA, but newer ones used the PCI Express connection instead for higher speed.

WD's demo indicates that it believes hard drives will benefit from PCI's speed. It wasn't immediately clear whether the demo used a traditional hard drive or one of the new hybrid designs that combine a hard drive with a small SSD for faster access to some data. Hybrid designs are more likely to run into speed limits of SATA earlier.

It's not a hard choice to make, since industry engineers from companies like Intel, Hewlett-Packard, and Western Digital already decided PCI Express is the future. They've created a standard called SATA Express that can accommodate either SATA or PCI Express connections, an approach that should ease the transition from one to the other.

The industry group overseeing the technology, SATA-IO, considered a new version of SATA to keep up with faster devices, but concluded it would take two years of effort and would yield an approach that consumed more power than PCI Express. Thus, it embraced PCIe.

"SATA Express enables a migration path to PCIe," said Paul Wassenberg, Director, Product Marketing at Marvell Semiconductor, in a 2013 presentation (PDF) about the approach.

In other words, SATA isn't dead yet, but it's on its way.