Moving A Petabyte of Data

(With apologies for the headfake of posting this entry then taking it down - my fingers were working faster than my brain, and I accidentally posted the entry without completing it. Or proofreading it.) I made a speech last week at which I asserted it was faster to send a petabyte of data from San Francisco to Hong Kong by sailboat, than by the internet. I got quite a few "how can that possibly be true?" kinds of questions, so here's the math. (Full disclosure, I am a mathematician by training, which guarantees me a lifetime of small "off by one" errors in all subsequent calculations - so if I get something wrong, be gentle). A petabyte is a thousand terabytes, which is a million gigabytes, or a billion megabytes. Or 8 billion megabits. With me so far? So if you had a half megabit per second internet connection, which is relatively high in the US (relatively low compared to residential bandwidth available in, say, Korea), it'd take you 16 billion seconds, or 266 million minutes, or 507 years to transmit the data. Can you sail to Hong Kong faster than that? At a full megabit, just divide the time in half. Even at a hundred megabits (about the highest, generally available, of any carrier I've seen), it's a few years. As Hal Stern once said to me, "Never understimate the bandwidth of a station wagon full of storage driving down the [New] Jersey Turnpike" - and now you understand why tape based storage has su...

Date: March, 12 2007
Url: http://blogs.sun.com/jonathan/entry/moving_a_petabyte_of_data

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