Bandwidth of a 747 hauling Blu-ray discs

Go read this post at Peter Murray’s Disruptive Library Technology Jester.

And then go read the comments. Specifically the second one, where Peter Murray responds to my offhand suggestion that the bandwidth of a station wagon full of computer tapes pales compared to that of a 747 (in cargo mode) full of 50GB Blu-ray discs.

Murray, being a librarian [and, full disclosure, a long-time friend], actually did the research to determine the effective bandwidth of such a delivery vehicle. It stands up pretty well to any current network plans.

Go on to the third and fourth comments. I upped the ante. Peter had assumed slimline jewel boxes to hold the Blu-ray discs, taking half the space of regular jewel boxes. Because of some work I was doing with my CD collection, I was aware of Office Depot CD Double Slim Jewel Cases (although I didn’t use the formal name), which actually hold two discs in a slimline case.
That ups the ante, making the effective bandwidth 74 terabits per second. (I noted that you could nudge that up past 100 terabits per second by using Tyvek sleeves instead of jewel boxes, but at the expense of unprotected discs–see Peter’s response, with which I fully agree.)

By comparison, the new and improved Internet2 backbone will offer 100 gigabits per second bandwidth.
The lesson here: If you really have huge quantities of data to move, there’s still a lot to be said for physical transport.

Now: Anyone want to figure out the weight of all those Blu-ray discs and jewelboxes, and whether they’d exceed the carrying capacity of a 747?

9 Responses to “Bandwidth of a 747 hauling Blu-ray discs”

  1. Dorothea Salo Says:

    Between you, you two nearly ruined an expensive Kinesis keyboard. Lucky it withstands water.

  2. walt Says:

    We do what we can. (Well, Peter does what he can. I just provided assistance.)

  3. Peter Murray Says:

    Great, Walt! Now if I get /.-ed (or LISnews-dotted), I’ll know who to thank. :-) As you point out, it all just goes to show how some of the “old fashion” ways of doing things are orders of magnitude better than some of these new-fangled things. (Although you will never catch me admitting that AACR-as-description/MARC-as-transport is orders of magnitude better than some of the new-fangled things we’ve got now.)

    Hmmm — come to think of it, the first flight of the Boeing 747 is just about the same time as LC MARC pilot project!

  4. walt Says:

    I believe MARC has served extremely well for an uncommonly long time, particularly for a machine-readable format (possibly because Henriette Avram and partners really were a LONG way ahead of their time). I believe a range of other tools makes sense for some purposes…but that we’ll be using MARC-via-XML or MARC-via-whatever for a while yet, one way or another, for materials that justify that level of precision. But orders of magnitude? Nahh.

    AACR: I’m not going there under any circumstances.

    Oh, I won’t get you /.ed, I don’t think: My readership isn’t that big.

  5. Thom Hickey Says:

    I just happened to recently purchase a box of 100 slimline cases and the CDs to go in them. Together they came to just over 10 pounds, or about 50 grams/CD. Given the 1,488,800 CDs as what a 747 can hold, the total load should be something like 75,000 Kg, or 75 metric tons. Looking at the empty vs. the fully loaded weights of a 747, it should lift that easily.
    –Th

  6. walt Says:

    Thom,

    Thanks for adding another hard fact to this remarkable discussion. I need to ask you and Peter both for permission to run a mildly-edited version of this whole discussion to a future issue of Cites & Insights; it’s too good to limit to W.a.r.’s smaller audience!

    We actually upped the ante by using the two-disc slimline cases, doubling it to 2,977,600–but that doesn’t come close to doubling the weight, since a substantial percentage of the disc-plus-case weight is the case itself. (Netflix would be in trouble if a DVD weighed more than about 25g, since that would substantially increase their postage costs–figuring 3g for the disc sleeve and mailer combined and staying within an ounce or 28g.) My rough guesstimate was somewhere around 90 tons (not metric tons), but that’s a rough guesstimate. Still, I believe, well within a 747′s capacity.

    Peter, Thom: Any objection to quoting this whole discussion in Cites & Insights? Collaborative investigation at work…

  7. walt Says:

    And if you printed out the contents of those 2,977,600 Blu-ray discs, and taped all the output together (taping on the short side of each page), how many times would the result reach to the moon and back?

    I hope nobody makes an attempt to answer that question. I pose it because someone somewhere linked to a very odd page (one of those that undermines the idea that “.edu” confers any special gravitas), which had a comment about 55 billion web pages that, if printed out, would reach to the moon and back several trillion times.

    Obvious hyperbole, to be sure, but it raised a fundamentally unanswerable and very silly question that took no more than two minutes to answer (noting that the answer is meaningless): Just under 48.

    That is, if each web page fits on a single sheet of 8.5×11″ paper (obvious nonsense, but work with me here), and if you could solve the minor engineering problems, and if the moon actually had a perfectly circular orbit at its average distance from Earth, rather than the elliptical orbit it actually has, then… that taped-together space monster would be right around 47.7 times as long as the distance from the earth to the moon. (It’s Webra!)

    Now, if there were actually 48.4 billion web pages…(the length of the Wikipedia entry related to this final thought says something about Wikipedia. Maybe.)

  8. Peter Murray Says:

    Thanks, Thom, for doing the math on the weight. It is good to know that, should anyone find a real need to load up a Boeing 747 full of Blu-ray disks, the weight limit will not be exceeded.

    Walt, permission to reprint granted! (It was probably implicit with DLTJ’s Creative Commons By-NC-SA license, but might as well be explicit.)

    Your comment to my comment about MARC is still buzzing around in my brain. I can’t quite put a finger on it yet, but that string of words is niggling the ‘jester’ side of my persona.

  9. walt Says:

    Peter: It’s the “SA” that made me ask, since it’s not part of the C&I license. Thanks. And I’m sure the jester will show up when it’s time.


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