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

7.2 Diagrams for Functionally Structured Methods

7.2.1 Context Diagrams

The purpose of a context diagram is to show the relationship between the system software and its environment. It portrays the complete system in its simplest form: a set of external items connected to a software black box, as shown in Figure 7.1(a):

Figure 7.1: Context diagram — functional flow diagram notation

It contains:

  • A single unit representing the complete software system
  • The external items that this software interfaces with
  • Signal/data flows into and out of the software

The result of applying these ideas to a hypothetical anti-skid braking system is shown in Figure 7.1(b). This would be used in concert with the system operational description contained in the SOR document. Details concerning system behavior, signal levels, required response rates, and so on are normally tied in with the context diagram documentation.

The information presented in...