1. Drivers of evolution

The evolution of computers, from the Eniac machine considered the first computer (1946) to the computers of the mid-2010s, is essentially the result of three factors:

• the technological evolution of computer components (processors, memory, input-output devices) with two main periods, before and after the birth and use of integrated circuits;

• application needs, from data center computing to personal computing with the personal computer and the "invisible" computing of embedded and mobile systems;

• economic constraints, which lead to different characteristics depending on whether the target is the "consumer" computer, the supercomputer reserved for "heavy users" (meteorology, nuclear industry, automotive industry, etc.), the "embedded system" in an automobile, mobile components...