Embedded System Design

A unique feature of this open access textbook is to provide a comprehensive introduction to the fundamental knowledge in embedded systems, with applications in cyber-physical systems and the Internet of things. It starts with an introduction to the field and a survey of specification models and languages for embedded and cyber-physical systems. It provides a brief overview of hardware devices used for such systems and presents the essentials of system software for embedded systems, including real-time operating systems. The author also discusses evaluation and validation techniques for embedded systems and provides an overview of techniques for mapping applications to execution platforms, including multi-core platforms. Embedded systems have to operate under tight constraints and, hence, the book also contains a selected set of optimization techniques, including software optimization techniques. The book closes with a brief survey on testing. This fourth edition has been updated and revised to reflect new trends and technologies, such as the importance of cyber-physical systems (CPS) and the Internet of things (IoT), the evolution of single-core processors to multi-core processors, and the increased importance of energy efficiency and thermal issues

High-Performance and Time-Predictable Embedded Computing

Nowadays, the prevalence of computing systems in our lives is so ubiquitous that we live in a cyber-physical world dominated by computer systems, from pacemakers to cars and airplanes. These systems demand for more computational performance to process large amounts of data from multiple data sources with guaranteed processing times. Actuating outside of the required timing bounds may cause the failure of the system, being vital for systems like planes, cars, business monitoring, e-trading, etc. High-Performance and Time-Predictable Embedded Computing presents recent advances in software architecture and tools to support such complex systems, enabling the design of embedded computing devices which are able to deliver high-performance whilst guaranteeing the application required timing bounds. Technical topics discussed in the book include: Parallel embedded platforms Programming models Mapping and scheduling of parallel computations Timing and schedulability analysis Runtimes and operating systems The work reflected in this book was done in the scope of the European project P SOCRATES, funded under the FP7 framework program of the European Commission. High-performance and time-predictable embedded computing is ideal for personnel in computer/communication/embedded industries as well as academic staff and master/research students in computer science, embedded systems, cyber-physical systems and internet-of-things.info:eu-repo/semantics/publishedVersio

Satisfying hard real-time constraints using COTS components

L'utilizzo di componenti COTS (Commercial-Off-The-Shelf) è sempre più comune nella produzione di sistemi embedded real-time. Prodotti commerciali, come periferiche di Input/Output e bus di sistema, vengono utilizzati in sistemi real-time al fine di ridurre i costi, il tempo di produzione, ed aumentare le performance. Sfortunatamente, hardware e sistemi operativi COTS sono progettati principalmente per ottimizzare le performance, ma con poca attenzione verso determinismo, predicibilità ed affidabilità. Per questa ragione, molte problematiche devono ancora essere affrontate prima di un loro impiego in sistemi real-time ad alta criticita'. In questa tesi abbiamo centrato la nostra attenzione su alcune delle piu' importanti sorgenti di impredicibilita' che devono essere rimosse al fine di integrare hardware e software COTS in sistemi hard real-time. Come prima cosa abbiamo sviluppato ASMP-Linux, una variante di Linux che minimizza overhead e latenza del sistema operativo. Successivamente abbiamo progettato ed implementato un nuovo sistema di gestione dell'I/O, basato sul Real-Time Bridge, un nuovo componente hardware che fornisce isolamento temporale sui bus COTS e rimuove le interferenze fra periferiche di I/O. E' stato anche sviluppato un Multi-Flow Real-Time Bridge per assicurare predicibilita' nel caso di periferiche condivise. Infine abbiamo proposto PREM, un nuovo modello di esecuzione per sistemi real-time che elimina le interferenze fra periferiche e CPU, e quelle fra processi ad alta criticita' ed interruzioni hardware. Per ognuna delle nostre soluzioni saranno descritti in dettaglio gli aspetti teorici, l'implementazione dei prototipi ed i risultati sperimentali.Real-time embedded systems are increasingly being built using Commercial Off-The-Shelf (COTS) components such as mass-produced peripherals and buses to reduce costs, time-to-market, and increase performance. Unfortunately, COTS hardware and operating systems are typically designed to optimize average performance, instead of determinism, predictability, and reliability, hence their employment in high criticality real-time systems is still a daunting task. In this thesis, we addressed some of the most important sources of unpredictability which must be removed in order to integrate COTS hardware and software into hard real-time systems. We first developed ASMP-Linux, a variant of Linux, capable of minimizing both operating system overhead and latency. Next, we designed and implemented a new I/O management system, based on real-time bridges, a novel hardware component that provides temporal isolation on the COTS bus and removes the interference among I/O peripherals. A multi-flow real-time bridge has been also developed to address interperipheral interference, allowing predictable device sharing. Finally, we propose PREM, a new execution model for real-time systems which eliminates interference between peripherals and the CPU, as well as interference between a critical task and driver interrupts. For each of our solutions, we will describe in detail theory aspects, as well as prototype implementations and experimental measurements