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Provides information on component-based software for embedded systems. Advantages of component-based design software; Definition of component software; Features of embedded systems.

Real-time computing is an enabling technology for many important application areas, including process control, nuclear power plants, agile manufacturing, intelligent vehicle highway systems, avionics, air-traffic control, telecommunications, multimedia, real-time simulation, virtual reality, medical applications, and defense applications. In particular, almost all safety-critical systems and many embedded computer systems are real-time systems. Further, real-time technology is becoming increasingly important and pervasive, more and more infrastructure of the world depends on it. Real-time computing is an enabling technology for many current and future applications that affect public safety, competitiveness, the economy, and life-style. Many results have been developed, but difficult research and transfer of technology issues remain. For example, real-time research has yet to grapple with three major realities concerning real-time applications. One proposed strategic decision is to develop a major funding and international research initiative in real-time computing to capitalize on current results, establish generic technology for the future, and thereby pay large dividends for safety and the economy.

Real-time systems are those systems in which the correctness of the system depends not only on logical results of computation but also on the time at which those results are produced. They span a broad spectrum of complexity from very simple microcontrollers in embedded systems to highly sophisticated, complex and distributed systems. Most embedded systems consist of a small microcontroller and limited software situated within some product such as a microwave oven or automobile. However, with the increasing sophistication of such systems, powerful microcontrollers and digital signal processing chips are commonly used, as are off-the-shelf real-time operating systems and design and debugging tools. Distributed multimedia have produced a new set of soft real-time requirements. Real-time principles lie at the heart of distributed multimedia, but without the concomitant high reliability requirements found in safety-critical, hard real-time systems. The confluence of real-time databases, multimedia and real-time control has great potential for moving application areas such as manufacturing and process control into the next generation.

Quality-aware realtime Embedded DataBase (QeDB) is a database for data-intensive real-time applications running on embedded devices. Currently, databases for embedded systems are best effort, providing no guarantees on their timeliness and data freshness. Existing real-time database (RTDB) technology cannot be applied to these embedded databases since it hypothesizes that the main memory of a system is large enough to hold the entire database. This, however, might not be true in data-intensive real-time applications. QeDB uses a novel feedback control scheme to support QoS in such embedded systems without requiring all data to reside in main memory. In particular, our approach is based on simultaneous control of both I/O and CPU resources to guarantee the desired timeliness. Unlike existing work on feedback control of RTDB performance, we implement and evaluate the proposed scheme on a modern embedded device. The experimental results show that our approach supports the desired timeliness of transactions while still maintaining high data freshness compared to baseline approaches. [ABSTRACT FROM AUTHOR]