Bandwidth of an SUV full of DVDs

Bandwidth of a SUV full of DVDs

First the Megabytes

A friend of mine owns a Chevrolet Suburban. The measurements were taken on his unit. (Thanks William and Josh). Folding down the back seats, the cargo space is 106 inches long, 62 inches wide and 36 inches high. DVSs seem to fit nicely in a 5" x 5" footprint. At MicroCenter they were selling spindles of 100 CDROMs in a case about 8" high. I’ll assume DVDs are about the same thickness. Rounding this says that on the floor of the suburban would fit a matrix of 12 by 21 CDROMs and we could stack them 450 high if we had a suitable spindle. So the suburban could hold 12x21x450=113,400 DVDs. What is the data capacity of such? At 4.7 Gigabytes per DVD, we come out with 113,400 x 4.7 = 532,980 Gb Megabytes, 532.98 Terabytes.

Now the Seconds

Consider a one-way trip from Washington, DC to San Francisco California (MAE East to MAE west). My road atlas gives 2890 miles (about 21 miles shorter than New York City to Los Angeles). Assuming we have two drivers and haul as fast as legally possible (averaging 50 MPH) this gives us a driving time of 2890/50 = 57.8 hours. This is reasonable, because the winning time in the Fireball Baker Sea-to-Shining-Sea Memorial race is typically under 36 hours.(This is the race that has inspired such cinematic bombs as Gumball Rally and The Cannonball Run) How many seconds is this? 57.8 hours x 60 minutes/hour x 60 seconds/minutes = 208,080 seconds.

Bandwidth = Megabytes / Second

532,980 Gigabytes / 208,080 seconds = 2.56 Gigabytes/Second.How does this compare with fiber?On October 15th, 2003, CNN reported that CalTech and CERN broke the internet speed record with a sustained transfer rate of 5.44 Gigabits/second. Allowing for the 8x between bits and bytes, it seems that the SUV has about four times the current maximum network bandwidth.This illustrates that bandwidth isn’t everything, one needs low latency as well to be useful. A week of turn-around time of data going from coast to coast and back isn’t very useful, no matter what its bandwidth.