Which has more bandwidth, a truck full of DVDs or a data cable?

Just vague curiosity. Imagine you have a semi-trailer full of DVDs – that’s got to be in the tens of thousands, maybe even the hundreds of thousands if you fill it to the brim. Each DVD holds 4.7 GB, so we’re talking about what, half a petabyte or so? Am I way off here? Let’s assume there’s no cardboard or jewel cases.

At 60 MPH, a semi is going 88 feet per second. If the trailer is, for convenience’s sake, 44 feet long, it gets all that data past a specific point in half a second.

Is there ANY data cable, fiber optic or otherwise, capable of transmitting a petabyte per second?

I asked a similar question a little while ago that took a turn towards your question.

http://boards.straightdope.com/sdmb/showthread.php?t=278609&highlight=fastest

The speed of the truck going past a point is not really a useful way to quantify bandwidth here. It is more important to use the time from loading the truck until it is unloaded at the destination. The truck probably still wins but that is answering the more important question how long does it take to deliver X amount of bits.

It’s only a petabyte a second burst. To have it sustained, you would have to have a string of trucks bumper to bumper. And no, it’s not possible, even internal busses can’t get 1 petabyte a second.

The way that you are quantifying it is not quite right. The truck has to travel from point A to point B to “transmit”. The cable works at near the speed of light.

I did the math for one example:

The truck and cable “race” from New York To LA

18 wheelers can carry up to 42000 pounds. A DVD weighs about 100 grams or 0.220462262 pounds

That means the 18 wheeler can carry about 190,500 DVD’s by weight which shouldn’t fill the truck up by space (cube).

Those DVD’s hold 895000 gigabytes or .85 petabytes total

The journey is about 55 hours driving taking about 198000 seconds.

895000 gigabytes / 198000 seconds = 4.5 GB/second transfer.

If you allow for many more hours loading, unloading, and unpacking, the contest isn’t hugely lopsided for the truck versus the fastest lines. The truck would win easily for now but there is promise that it may not be that way in 20 years.

And, really, you should consider the time spend burning and ripping those DVDs as well. Moving a pile of plastic from one warehouse to another only qualifies as “data transfer” using the loosest of definitions.