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USB 3.0 Is Ten Times Faster; Get It In 2010

Posted by timothy on from the slow-boat-to-the-racetrack dept.

thefickler writes "Seagate and Symwave are jointly demonstrating the first consumer applications of USB 3.0 at CES, showing a Seagate FreeAgent drive running through a Symwave USB 3.0-compatible storage controller device. According to Symwave, this will result in 'speeds previously unattainable with legacy USB technology.' Which means, if you understand PR-write, it will be much faster."

10 of 280 comments (clear)

  1. That speed comes at a cost by stokessd · · Score: 4, Informative

    Given that USB is PIO and not DMA, the faster the bus runs the more processor intervention is needed. Given how cheap and fast our processors are, that's not a huge deal, but it's not like a DMA based transfer just got faster, it means that the processor is going to be more busy too.

    PR-write or not, it will be a PITA just like USB2.0 until it's built in and common.

    Sheldon

    1. Re:That speed comes at a cost by Vihai · · Score: 5, Informative

      USB is PIO and not DMA? You understand that PIO/DMA transfer modes only meaningful for Parallel ATA devices?

      That's because the ATA interface was originally THE 16-bit system bus (AT bus) and the disk controller was onboard on the disks (thus the name IDE - Integrated Drive Electronics).

      So, the CPU accessed the disk controller through the AT bus which was originally programmed I/O and then started using DMA.

      Of course, the system bus quicky become different and faster (FSB + PCI) thus the ATA interface became a disk attachment interface instead of the system bus and an additional controller was put between the system and the disk.

      USB is a completely different beast. The "bus" actually transfer packets (URBs) and all USB controllers use DMA to transfer URBs to the main memory... So, no PIO/DMA stuff is involved....

  2. USB3 whitepaper by whyde · · Score: 5, Informative

    Most of the replies so far show a glaring lack of knowledge of what USB3 really is. Honestly, it only bears a passing resemblance to its predecessors, and is a closer relative to PCIe. If you want more technical information, Denali has a good whitepaper (registration required):

    http://www.denali.com/en/events/usb3_whitepaper/?EB20090105

    1. Re:USB3 whitepaper by legirons · · Score: 3, Informative

      Most of the replies so far show a glaring lack of knowledge of what USB3 really is. Honestly, it only bears a passing resemblance to its predecessors, and is a closer relative to PCIe. If you want more technical information, Denali has a good whitepaper (registration required):

      And the real info can of course be found at https://secure.wikimedia.org/wikipedia/en/wiki/Usb3#USB_3.0

      weirdly, wikipedia doesn't seem to include any of that stuff about upgrade to our standard or your company will die - you might need to turn to an industry-funded news source for the full story ;)

  3. Re:And how much cpu power is needed at that speed? by Daniel+Dvorkin · · Score: 3, Informative

    I hate to say this, but Firewire's dead. Apple invented it and they've been the main ones pushing it; now that they're pretty clearly planning to get rid of it, there are no major industry players with an interest in its survival. I agree that it's a far superior standard for pushing any meaningful amount of data around, so I'm not at all happy about this state of affairs, but so it goes.

    --
    The correlation between ignorance of statistics and using "correlation is not causation" as an argument is close to 1.
  4. PIO vs. DMA by Alwin+Henseler · · Score: 5, Informative

    You understand that PIO/DMA transfer modes only meaningful for Parallel ATA devices?

    That's the meaning in traditional sense. But you can also use this distinction in a wider sense:

    • PIO: The CPU has to manage / monitor / do every little step in the process.
    • DMA: The CPU sets parameters, give a start signal, and then just waits (ehm, can do something else in the meanwhile), while dedicated hardware does all the boring work, like tranfer individual bytes / words of data to main memory. When ready, the CPU gets a signal (for example: an interrupt) that the transfer is complete. This may be used to describe many hardware-supported tasks, not just IDE harddisk controllers.

    How much of an advantage this is, depends on how complex the initial parameter setup is, how much of the work is done by hardware vs. CPU, transfer speed, how large transferred blocks are, how often transfer occur, etc. etc. Besides overall speed, a big advantage is that the CPU can do other things (like decode a video stream, respond to keyboard / mouse input) while a tranfer continues in the background. This allows a system to feel much more responsive.

    You state that USB controllers use DMA, parents says not. I don't know which is true. Perhaps there is DMA support for USB controllers, but the packets are small enough and flowing at a high enough rate that it feels like the CPU is doing all the work?

    1. Re:PIO vs. DMA by Agripa · · Score: 3, Informative

      That was the impression I got from the various sources I have read. I also think I remember reading that they are planning to fix this with USB 3.

      I read through Intel's EHCI specifications and from what I understood, while DMA is supported it still requires double buffering because of alignment issues. The interrupt rate and required CPU supervision were probably not a problem until the 480 Mbits/sec transfer rate was implemented.

  5. Re:Faster data is great, but... by pchan- · · Score: 4, Informative

    You'll be glad to know that it does, but I'm not sure if it's enough to run a 3.5" Magnetic Hard drive.

    "Maximum bus power is increased to 150mA per unit load (+50% over USB 2.0)."

    A solid State drive, on the other hand...

    Power is measured in Watts, not Amps. USB3 is still at 5V, but now lets you negotiate up to 1 Amp of current (USB2 limits at 500 mA). So, that's 5 Watts of power. the 150mA draw is the maximum current you are allowed to draw in before negotiating up to verify the host supports more.

  6. Re:76 Virgins!?!?!? by Jafafa+Hots · · Score: 4, Informative

    There has to be at LEAST 76 virgins on slashdot.

    --
    This space available.
  7. Re:What about the rest of us? by necro81 · · Score: 5, Informative

    One other problem Firewire had in becoming widespread was that it required a more beefy, dedicated chip. As far as I understand it, Firewire is implemented mostly in the chip, cutting out the CPU, and creates a more-or-less guaranteed bandwidth. This is why it was popular with camcorders - you could always be sure that you could transfer video in realtime. Same for high-end sound equipment.

    USB, on the other hand, while it has its own controller chip, is moderated largely by the CPU and memory bus. If the computer is under heavy load, the USB throughput suffers. Peripheral devices are at the mercy of the host to control things. This is fine for things like mice and keyboards, which transfer relatively little data semi-asynchronously. You don't need such a robust high speed bus for such lightweight peripherals. But for hard drives and other devices, USB has some catching up to do.

    Royalties aside, the Firewire chipset that could implement a high-speed bus robustly cost more than the more lightweight USB controller. In the particular case of the iPod, a portable device, having the Firewire controller eventually took more board space than Apple was willing to provide. While every computer had a mouse and keyboard, not every computer was made with the ability for connecting external drives. So there, too, the economics played in USB's favor.