Nowadays and future embedded and special purpose systems need a qualitative step forward in the research efforts better than continue in quantitatively improve the designs: it's time for scaling-out architectures, instead of scaling-up frequency. As transistor count is still increasing as expected by Moore's law, recent challenges like wire-delay, design complexity, and power requirements are becoming more and more important. These problems are preventing the evolution of chip architecture in the directions followed in the previous decades, when clock frequency as well could scale-up with Moore's law. Many researchers and companies have started to look at building multiprocessors on a single chip, following both past and novel design solutions: no doubt that we are all expecting several cores on a single chip in the near future.