Words about things and stuff…


Posted on November 17, 2010 by | No Comments

A lot of technologies come and go. That is just the nature of computers and computer technology. But one thing that has been around since the beginning of computing is sneakernet.

What is sneakernet? Why hasn’t it died like the floppy disk? Will it die… ever?

Sneakernet is a method of transferring data between computers by physically carrying the data from one computer to another on physical media like a floppy disk/tape/CD/DVD/bluray/USB thumb drive/external HDD ect… You could say that sneakernet is a network/network protocol.

Sneakernet is used to transfer large amounts of data when it would be impractical to transfer the data over other types of networks. Where two networks may not be compatible sneakernet may be used to transfer data between these networks. Even postal services like the US Postal Services offer a sneakernetwork service.

Sneaker net is often used to illustrate the trade off between latency and throughput.

Never underestimate the bandwidth of a station wagon full of tapes hurtling down the highway. —Tanenbaum, Andrew S. (1996). Computer Networks. New Jersey: Prentice-Hall. pp. 83. ISBN 0-13-349945-6.

Sneakernets can achieve massive throughput but at the cost of extreme latency. Consider person A had a 4.7 GB DVD of data that person B wants. Person A could throw up an ISO of the DVD online so that person B could download it over the internet. Latency over the internet is usually measured in milliseconds but even with a modest, lets say they have a 512 kbps, connection and they can download the file at 50 kB/s it could take a day or longer to download the file. Let’s say that Person A lives an hour away from Person B. Person A could burn a copy of the DVD and deliver the data to person B in an hour. The latency is an hour but the throughput is about 1305 kB/s.

In theory a Boeing 747 can hold 595,520,000 Gigabits of data on 1,488,800 Blu-ray DVDs. Assuming that the Blu-rays are cased in slim jewel cases that each hold 1 Blu-ray. The time (latency) to travel between point A and point B is 4.46 hours, but the throughput is 37Tb/s! Try doing that on any network right now. [source]

And there are plenty of real world examples of sneakernet useage. In September 2009, Durban company Unlimited IT reportedly pitted a carrier pigeon against South African ISP Telkom to transfer 4 GB of data 60 miles (97 km) from Howick to Durban. The pigeon, carrying the data on a memory stick, arrived in one hour eight minutes, with the data taking another hour to upload. During the same two-hour period, only about 4% of the data had been transferred over the ADSL link. A similar experiments was conducted in England in September 2010; the “pigeonnet” also proved superior. [source http://en.wikipedia.org/wiki/Sneakernet#cite_note-7]

Amazon use sneakernet. [source] Even Google uses sneakernet. [source]. Netflix effectively uses sneakernet by mailing out DVDs to customers.

Sneakernet has also shown up in fiction, like in Terry Pratchett’s Going Postal novel where a contest between a horse-back courier and the “Grand Trunk Clacks” (a semaphore line) is arranged to see which is the fastest way to transmit a book. Live Free or Die Hard depicts a digital thief attempting to download 500TB of financial data to a suitcase sized package(s). The 1995 film Johnny Mnemonic, based on the short story by William Gibson, stars Keanu Reaves as a digital courier with 320 GB of corporate data transported in his head. Gibson’s 2007 novel Spook Country also featured sneakernets, with iPods being the storage device used to clandestinely move information.

So sneakernet has been around for many years and will still be for many years to come thanks to the tremendous throughput that it offers.

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