7. In a nutshell

The problems of integration tend to favor homogeneous architectures, because they are naturally redundant, but these are not the most efficient in terms of performance per Watt consumed, nor in terms of surface area and therefore production cost. Embedded systems therefore cover a vast range of hardware architectures, depending on the class of applications for which they are intended. Unlike conventional OSes, embedded OSes are designed to run on these different architectures. The design of such OSes, although based on concepts similar to those of the computer world, brings with it new issues. These include :

• rapid adaptation to very different platforms, which requires the definition of a complete, watertight hardware abstraction layer;

• taking time into account in task scheduling choices, which requires knowledge of their...