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Whither The 1.21 Jigowatts?

Intel’s X-Lab: Tomorrow’s Network Happens Here
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Whither The 1.21 Jigowatts?

Those who have seen Back to the Future no doubt recall Doc and his revelation about the DeLorean’s “1.21 jigowatt” power requirements. Thankfully, we had neither plutonium nor lightning strikes present on our tour, but we did have a flux capacitor. That’s the cylindrical capacitor housed within the bisected metal block you see above. The data cable sets inside the center conductor, and it literally is in flux—hence the name. In electromagnetic field theory, there are lines of flux, so X-Lab engineers joke about it being the infamous “flux capacitor.” In reality, all capacitors are flux capacitors. Gotta love that geek humor. Anyway, the inserted cable has noise coupled onto all four of its wire pairs simultaneously.

Techs examine several signal types through the flux capacitor test to assess their effect on differential signaling, which assists with noise cancelation.

“Differential signaling is a very brute force method of noise cancellation,” explained Pete. “We split the signal, invert one half, run this split signal into a difference amplifier, and look at the resulting signal. If you have a signal that is common to both halves—meaning the same phase, polarity, and amplitude—coming into the receiver, the signals should cancel. Well, that’s great in math, but in the real world, one pair of wire will probably be a little longer or shorter than another, so you have an offset in time. They’ll probably be manufactured slightly differently, so the amplitude or power will be different. You subtract two things that are not identical but close. That’s why you get a little noise left over at the end.”

I asked if this was the same principle behind active noise cancelation in headphones.

“That’s a good way to think about it,” he said. “By the way, our alien crosstalk test uses a differential noise source. It comes in and stays there. For common-mode noise, we’re hoping that the system will work really well, the noise will balance, and be eliminated. But in the real world, it doesn’t always happen.”

(Note: For those who question the spelling of “jigowatts,” see http://www.imsdb.com/scripts/Back-to-the-Future.pdf at the famous shot 67.)

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  • 0 Hide
    dogman_1234 , January 17, 2011 4:05 AM
    Anyone else notice the Guy Fawkes mask in the background?
  • -1 Hide
    super_tycoon , January 17, 2011 6:38 AM
    dogman_1234Anyone else notice the Guy Fawkes mask in the background?


    It's existence is noted in the text for pic3, though I can only wonder why he has it. Is it good taste to associate yourself with 4chan and anon nowadays?
  • 0 Hide
    gmoney86 , January 17, 2011 7:10 AM
    I am not sure if I ever saw the sign to the X-Lab when working at Jones Farm, but I did always wonder what went on in the labs that were similar to it. They kind of looked like IT work rooms to me, though it makes sense to have a need for oscilloscopes, soldering irons, networking tools, etc. for certain R&D projects.
  • 2 Hide
    CvP , January 17, 2011 7:19 AM
    In picture #4 (elephant arm) :D 

    Thanks Toms for this article.
  • 2 Hide
    scook9 , January 17, 2011 2:25 PM
    Awesome article, I just finished me BSEE degree and now work in an network company where I help engineer servers so this is right up my alley!
  • 0 Hide
    Anonymous , January 17, 2011 4:28 PM
    This all started in 1990 with the creation of EtherExpress 16 by a handful of people led by a visionary leader, Steve Kassel.
  • 0 Hide
    williamvw , January 17, 2011 10:30 PM
    super_tycoonIt's existence is noted in the text for pic3, though I can only wonder why he has it. Is it good taste to associate yourself with 4chan and anon nowadays?

    My guess is that it was just a fun-looking mask someone had brought to the lab, perhaps because they also enjoyed "V for Vendetta." (I did!) I'd wager that the X-Lab crew had no idea of the mask's fleeting association with 4chan's anti-Scientology protests, much less the religious motivations behind Fawkes's attempted regicide. Let's not accuse good people without cause.
  • 1 Hide
    chovav , January 18, 2011 10:02 AM
    Excellent article Tom (Willam actually). Nice reading, informative and geeky, just the way I like it. Amazing to see that they transfer 76TB in just one test (500,000,000*1518*100). Good job!
  • 0 Hide
    dEAne , January 19, 2011 12:46 AM
    I love this article - thanks for this info.
  • 0 Hide
    williamvw , January 26, 2011 6:50 PM
    chovavExcellent article Tom (Willam actually). Nice reading, informative and geeky, just the way I like it. Amazing to see that they transfer 76TB in just one test (500,000,000*1518*100). Good job!

    Yeah, I was stunned. I honestly expected some automated tests, maybe a few guys with scopes taking occasional signal readings -- NOTHING like what I saw. I'd assumed that a technology as old as Ethernet was pretty much a done deal and didn't require much hand holding at this point. I couldn't have been more wrong.
  • 0 Hide
    Anonymous , February 1, 2011 8:27 PM
    Does this have a PHY made by one of startups like Aquantia or Teranetics or is it a Broadcom PHY.
    I think we will be running 10GbaseT LOM in most datacenters soon.
  • 0 Hide
    Anonymous , February 7, 2011 3:30 PM
    You can buy them off of newegg, they use Teranetics PHY's (Logo under the heatsink).
  • 0 Hide
    woshitudou , February 12, 2011 12:57 AM
    Can Toms quit with the galleries or add a '10 per page' mode? Clicking next and having the entire page reload 50 times and having to scroll down 50 times is stupid. It's like we're suck in 2001 web design practices.
  • 0 Hide
    juanc , February 25, 2011 3:06 PM
    The question is... where is QAM in networks? Why not? Is there anyone from Toms taking this question?
  • 0 Hide
    rebel1280 , May 18, 2011 4:44 PM
    Fun, great, informative and geeky. Loved reading every second of it. A nod and a drink to those guys for sure! By the way, i have IE9 and i cant post comments with it, have to use firefox for it, just an FYI. Not a big deal as i use FF anyways, just testing IE9.
  • 0 Hide
    quickmana , June 7, 2011 10:09 PM
    I don't know why but the picture of the engineer staring deeply into the glass struck an emotional tone with me.
  • 0 Hide
    Anonymous , November 1, 2011 9:50 PM
    Nice to see a TestEquity chamber in picture number 23!
  • 0 Hide
    faryalk90 , June 25, 2012 9:08 AM
    A very Nice and Helpful Post..Thanks for Sharing
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  • 0 Hide
    faryalk90 , June 25, 2012 9:09 AM
    A very Nice and Helpful Post..Thanks for Sharing
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