Tuesday, February 5, 2008

How much bandwidth does a man need, Mr. Tolstoy?

Earl comments that we probably already have enough, or nearly enough bandwidth to saturate human capacity, but not enough to satisfy our human desire for new shiny pretty things. Or at least I hope that's a reasonable paraphrase.

I would say it depends on what kind of information you're trading in. If you're dealing in metadata like who knows whom, or dealing in random facts like the score of every major sports event in the world, or in text like newspaper copy, even a dial-up connection can feed you information faster than you can process it.

If you're dealing in sound, a dial-up connection can certainly carry voice (that's what it was designed for, after all). Decent stereo sound requires more like 100kb/s (mp3 takes about a megabyte a minute). That's a bit beyond dial-up, but cable and DSL can handle it.

Analogously, if you want YouTube-quality video, you can certainly get that over cable or DSL, but plain DVD quality, at 4Mb/s, needs what's still an uncommonly big pipe. And that still leaves plenty of room before we hit the limits of perception. Those finely-tuned eyes of ours are bandwidth-hungry.

On the other hand, as Earl points out, you hit diminishing returns well before you hit the limits of perception. That last Mb/s of bandwidth doesn't improve the experience nearly as much as the first one. The difference between regular TV and HD is not nearly the difference between TV and no TV (and some would argue whether that last one represents an improvement, either).

Storage hardware is already entering a new regime of plenty. You can now get a terabyte disk off the shelf. My spell checker flags "terabyte", but soon enough we'll be throwing around (I'm guessing) "T" like we now throw around "gig" and "meg". Borrowing from those displays you see in the camera/music player department, a terabyte can hold:
  • A million minutes, or more than two solid years, of music.
  • Hundreds of thousands of high-quality photos.
  • Hundreds of hours of DVD-quality video.
For less than the cost of a humongous monitor to watch it on, you can now get enough disk to store your entire DVD collection and (likely) every home video you ever shot, plus your entire song collection. Or you could store every phone conversation you've ever had in your life (phone quality requires much less than mp3, in case you've spent more than two years of your life chatting).

If you have dial-up at 56Kb/s, it would take 4-5 years to fill a terabyte, assuming the connection is running full-tilt, constantly, with every bit recorded on the disk. When you're done with that, you'll probably be able to pop in a 10TB disk for the same price and keep going ... The question is, will you still have a 56Kb/s dial-up connection?

In the big happy family of Moore's law, bandwidth into the house is the poor cousin (processing power is the crazy uncle in the attic, but maybe I'll get to that later). At some point, bandwidth will reach the point that disk is reaching now, where we'll actually have to think a bit about how to use it all. Anomalously, that point still seems fairly far off.

But then, how much do we really need? In Tolstoy's famous story How much land does a man need? (which I haven't read), it turns out you need about three feet by six feet. By six feet deep.

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