Chapter 1


1.1. Why a network?

A network transmits information from point-to-point from an office, company, school, aircraft carrier or, more generally, from anywhere on the planet. Very often associated with the Internet, it has completely transformed the design of traditional computer systems. To remember this, one need only read the short story by sciencefiction writer Isaac Asimov who in the 1970s offered his vision of the computer industry evolution in the short story All the Troubles of the World1. For the 2000s, he forecast a gigantic computer called “the multivac”, which would control the entire planet. He went as far as predicting the election of the world president by this computer. Asimov writes that it encompassed Washington D.C. and its suburbs and that an army of civil servants was needed to run it.

To foresee the computer of the future, Asimov simply described the situation of the centralized computer systems of the 1970s and increased everything: the size of central units and the number of people needed to make them run. The footprint, the design and maintenance cost mean that this type of equipment is limited and reserved for important research and general interest tasks. Information is necessarily centralized in these points and resorting to a network is pointless.

What we can observe, in the 21st century, is radically opposed to Asimov’s vision. The systems are decreasing in size, increasingly powerful, numerous and specialized and their maintenance ...

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