Tuesday, January 18, 2011

How many was that again?

It's generally claimed but probably not true that IBM president Tom Watson said the world would need five computers. In 1980 many people thought the world needed just over four billion Internet addresses - wrong again! We know they believed this because that's how it was designed. All Internet addresses are numbers. The addresses we use - www.Braley.com for example - are immediately translated into a number (the real address of the site) before they are sent whizzing off to their destination. Imagine that you were setting up the records for a small town and decided to record every resident using a three digit number - after all it was a small town. Of course when person number 1,000 moves in, you have a problem.

That's exactly the predicament faced by the Internet - the 4.2+ billion Internet addresses are almost used up. People have seen this coming for a long time and created a new addressing system  that will be phased in over several years. Internet addresses are called IP addresses for Internet Protocol. The current version is IPv4 and the new version will be IPv6. IPv4 addresses consist of a 32 bit string of zeros and ones - bits. IPv6 will be 128 bits long. Keep in mind that every bit you add doubles the size of the maximum number. The fact that everything from cell phones to printers and refrigerators may get an IP addressed assigned in the future is no cause to worry since a 128 bit address is inconceivably large - a 4 followed by 38 zeros - just shy of a duodecilion!

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