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Component-based software engineering (CBSE) and the use of (de-facto) standard component models have gained popularity in recent years, particularly in the development of desktop and server-side software. This paper presents a motivation for applying CBSE to real-time systems and discusses the consequences of adopting a software component model in the development of such systems. Specifically, the consequences of adopting Microsoft's COM, DCOM, and .NET models are analyzed. The most important aspects of these models are discussed in an incremental fashion. The analysis considers both real-time systems in general, and a real-life industrial control system where some aspects the COM model have been adopted. It is concluded that adopting these models makes it possible to meet real-time requirements, but that some overhead must be expected and that special precautions may have to be taken to prevent loss of real-time predictability.

This chapter presents a case study from a global company developing a new generation of programmable controllers to replace several existing products. The system needs to incorporate support for a large number of I/O systems, network types, and communication protocols. To leverage its global development resources and the competency of different development centers, the company decided to adopt a component-based software architecture that allows I/O and communication functions to be realized by independently developed components. The architecture incorporates a subset of a standard component model. The process of redesigning the software architecture is presented, along with the experiences made during and after the project. An analysis of these experiences shows that the component-based architecture effectively supports distributed development and that the effort required for implementing certain functionality has been substantially reduced while, at the same time, the system's performance and other run-time quality attributes have been kept on a satisfactory level.

The use of software component models has become popular during the last decade, in particular in the development of software for desktop applications and distributed information systems. However, such models have not been widely used in the domain of embedded real-time systems. There is a considerable amount of research on component models for embedded real-time systems, or even narrower application domains, which focuses on source code components and statically configured systems. This paper explores an alternative approach by laying the groundwork for a component model based on binary components and targeting the broader domain of embedded real-time systems. The work is inspired by component models for the desktop and information systems domains in the sense that a basic component model is extended with a set of services for the targeted application domain. A prototype tool for supporting these services is presented and its use illustrated by a control application.

While the use of software component models has become popular in the development of desktop applications and distributed information systems, such models have not been widely used in the domain of embedded real-time systems. Presumably, this is due to the requirements such systems have to meet with respect to predictable timing and limited use of resources. There is a considerable amount of research on component models for embedded real-time systems that focuses on source code components, statically configured systems, and relatively narrow application domains. This paper explores the alternative approach of using a mainstream component model based on binary components. The effects of using the model on timing and resource usage have been measured by implementing example applications both with and without using the model. In addition, the use of a prototype tool for supporting software component services has been investigated in the same manner.

The use of software component models has become popular in the development of desktop applications and distributed information systems. The most successful models incorporate support for runtime services of general use in their intended application domains.There has been no widespread use of such models in the development of embedded real-time systems and much research is currently directed at defining new component models for this domain. We have explored the alternative approach of extendinga mainstream component model with run-time services for embedded real-time systems. A prototype tool has been developedthat generates code for a number of such services. To evaluatethis tool, we have conducted a multiple-case study, where four teams of students were given the same development task. Two teams were given the tool while the remaining two were not. This paper describes the design of the study and our initial analysis of the results.