Book Image

The Complete Edition - Software Engineering for Real-Time Systems

By : Jim Cooling
Book Image

The Complete Edition - Software Engineering for Real-Time Systems

By: Jim Cooling

Overview of this book

From air traffic control systems to network multimedia systems, real-time systems are everywhere. The correctness of the real-time system depends on the physical instant and the logical results of the computations. This book provides an elaborate introduction to software engineering for real-time systems, including a range of activities and methods required to produce a great real-time system. The book kicks off by describing real-time systems, their applications, and their impact on software design. You will learn the concepts of software and program design, as well as the different types of programming, software errors, and software life cycles, and how a multitasking structure benefits a system design. Moving ahead, you will learn why diagrams and diagramming plays a critical role in the software development process. You will practice documenting code-related work using Unified Modeling Language (UML), and analyze and test source code in both host and target systems to understand why performance is a key design-driver in applications. Next, you will develop a design strategy to overcome critical and fault-tolerant systems, and learn the importance of documentation in system design. By the end of this book, you will have sound knowledge and skills for developing real-time embedded systems.
Table of Contents (16 chapters)
Preface
15
Glossary of terms

12.5 Real-World Interfacing

12.5.1 Background

Many design processes pay scant attention to the handling of real-world interactions. Frequently, OO techniques treat interfacing rather dismissively, using "interface" or "boundary" classes that are peripheral to the design (no pun intended). In some ways, this view is understandable in desktop-type IT systems. However, to take the same approach for real-time embedded systems is, at best, risky; at worse, it can be extremely dangerous. Lutz [LUT93], for example, describes the experiences gained in the integration and system testing of the Voyager and Galileo spacecrafts. He found that the misunderstanding of interface requirements and the lack of detailed requirements for robustness were the primary causes of safety-related software errors. These accounted for 44% of all logged safety-related errors, as a result of the following:

  • Out-of-range input values
  • Non-arrival of expected inputs
  • The unexpected...