Why USB 3.0 Is So Much Faster

By Chris Preimesberger  |  Posted 2009-01-02 Print this article Print

The key to the breakneck speed of USB 3.0 is the vastly improved drivers, which are not "polling-type" mechanisms, O'Neill said.

"In a polling-type driver [which USB 1.0 and 2.0 use], every transmission had to be initiated and acknowledged by the CPU," O'Neill said. "Basically, in USB 1.0 and 2.0, the CPU was involved in handling every packet of data that was transferred [in the stream]. So just rewriting the protocol so that the CPU initiates the transaction but doesn't need to acknowledge every single packet-it only does it at the beginning and at the end."

Additionally, USB 3.0 features much-improved power management, O'Neill said.

"In an enterprise, for example, let's say you connect a PC to a USB hub with five ports, and then you connect a bunch of devices to it. Unless all those devices are asleep, the hub has to send a poll to every one of the client devices," O'Neill said.

"It's been a dirty little secret that USB claims to have effective power management, but in reality if you have more than one peripheral connected, the whole thing is broken. USB 3.0 has addressed that, so that each device is viewed independently from the host perspective," O'Neill said.

"So you can't effectively have all but one of the devices connected powered down and basically ... not 'woken up' to poll for data. Overall, power management is going to be a huge benefit for the end consumer."

Chris Preimesberger Chris Preimesberger was named Editor-in-Chief of Features & Analysis at eWEEK in November 2011. Previously he served eWEEK as Senior Writer, covering a range of IT sectors that include data center systems, cloud computing, storage, virtualization, green IT, e-discovery and IT governance. His blog, Storage Station, is considered a go-to information source. Chris won a national Folio Award for magazine writing in November 2011 for a cover story on Salesforce.com and CEO-founder Marc Benioff, and he has served as a judge for the SIIA Codie Awards since 2005. In previous IT journalism, Chris was a founding editor of both IT Manager's Journal and DevX.com and was managing editor of Software Development magazine. His diverse resume also includes: sportswriter for the Los Angeles Daily News, covering NCAA and NBA basketball, television critic for the Palo Alto Times Tribune, and Sports Information Director at Stanford University. He has served as a correspondent for The Associated Press, covering Stanford and NCAA tournament basketball, since 1983. He has covered a number of major events, including the 1984 Democratic National Convention, a Presidential press conference at the White House in 1993, the Emmy Awards (three times), two Rose Bowls, the Fiesta Bowl, several NCAA men's and women's basketball tournaments, a Formula One Grand Prix auto race, a heavyweight boxing championship bout (Ali vs. Spinks, 1978), and the 1985 Super Bowl. A 1975 graduate of Pepperdine University in Malibu, Calif., Chris has won more than a dozen regional and national awards for his work. He and his wife, Rebecca, have four children and reside in Redwood City, Calif.Follow on Twitter: editingwhiz

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