In this book we propose a new simulation platform specifically designed for modeling parallel and distributed architectures, which consists on integrating the model of the four basic systems into a single simulation platform. Those systems consist of storage system, memory system, processing system and network system. The main characteristics of this platform are flexibility, to embrace the widest range of possible designs; scalability, to check the limits of extending the architecture designs; and the necessary trade-offs between the execution time and the accuracy obtained. This simulation platform is aimed to model both existent and new designs of HPC architectures and applications. Then, the model can be focused on a set of the basic systems, or by the contrary on the complete system. Therefore, a complete distributed system can be modeled by integrating those basic systems in the model, each one with the corresponding level of detail, which provides a high level of flexibility. Moreover, it provides a good compromise between accuracy and performance, and flexibility provided for building a wide range of architectures with different configurations.