Doing Hard Time: Developing Real-Time Systems with UML, Objects, Frameworks, and Patterns

Product Author Bios

Bruce Powel Douglass is the Chief Evangelist for i-Logix, a leading producer of tools for real-time systems development. He contributed to the original specification of the UML and to the UML 2.0 as one of the co-chairs of the Object Management Group’s Real-Time Analysis and Design Working Group. Bruce consults for a number of companies and organizations, including NASA, on building large-scale, real-time, safety-critical systems. He is the author of seven other books, including Real-Time Design Patterns (Addison-Wesley, 2003) and Doing Hard Time (Addison-Wesley, 1999).

"This book will almost certainly become a seminal work in this field...the one book everyone will want to have both as a tutorial and as a reference."
--Larry McAlister, Senior Systems Architect, ENSCO, Inc.

The global demand for real-time and embedded systems is growing rapidly. With this increased demand comes an urgent need for more programmers in this realm; yet making the transition to real-time systems development or learning to build these applications is by no means simple. Real-time system designs must be written to meet hard and unforgiving requirements. It is a pursuit that requires a unique set of skills. Clearly, real-time systems development is a formidable task, and developers face many unique challenges as they attempt to do "hard time."

Doing Hard Time is written to facilitate the daunting process of developing real-time systems. It presents an embedded systems programming methodology that has been proven successful in practice. The process outlined in this book allows application developers to apply practical techniques--garnered from the mainstream areas of object-oriented software development--to meet the demanding qualifications of real-time programming.

Bruce Douglass offers ideas that are up-to-date with the latest concepts and trends in programming. By using the industry standard Unified Modeling Language (UML), as well as the best practices from object technology, he guides you through the intricacies and specifics of real-time systems development. Important topics such as schedulability, behavioral patterns, and real-time frameworks are demystified, empowering you to become a more effective real-time programmer.

The accompanying CD-ROM holds substantial value for the reader. It contains models from the book, as well as two applications that are extremely useful in the development of real-time and embedded systems. The first application, a UML-compliant design automation tool called Rhapsody (produced by I-Logix), captures analysis and design of systems and generates full behavioral code for those models with intrinsic model-level debug capabilities. The second application, TimeWiz, can analyze the timing and performance of systems and determine the schedulability of actions in multitasking systems.

Customer Reviews

72 of 81 people found the following review helpful Hard Times "Doing Hard Times", July 19, 2000 By  Arthur Schwarz - See all my reviews This review is from: Doing Hard Time: Developing Real-Time Systems with UML, Objects, Frameworks, and Patterns (Hardcover) The book appears to be a testament to "why I am good" rather than a description of the topic at hand. Editorially, figures don't match text, grammar is expansive and lacks understandability, it is difficult to determine whether words used are used in their English or technical sense, and the use of words requiring dictionary lookup is laudable in grade schools somewhat suspect in a book of this caliber (try 'reify'). Technically little scholarship is shown. The section titles are good, the author often strays from them. For analysis of embedded systems, trivial results are stated and no attention is given to their derivation nor to analysis or references to analysis. Little attention is paid topics beyond their brief statement. Much time is wasted on examples which show the authors work engagements but which do not illustrate the point at hand. Critical topics (for embedded systems) need greater attention and technical analysis rather than restating obvious... Read more Help other customers find the most helpful reviews  Was this review helpful to you?  Report abuse | Permalink  Comment (1) 31 of 33 people found the following review helpful Too wide and too optimistic?, February 26, 2001 By  Babak A. Farshchian (Trondheim, Norway) - See all my reviews This review is from: Doing Hard Time: Developing Real-Time Systems with UML, Objects, Frameworks, and Patterns (Hardcover) I read this book as a first introduction to OO real time computing. I liked the introduction that covers the three topics of OO, RT systems and fault tolerance (though it does not connect the three topics in any sense). I gave up reading the book after the chapter on method, though I skipped through the remaining chapters. The rest of the book was mainly old stuff on waterfall models and OOA/OOD. The whole book was also very commercial and connected to a specific product from the company that the author works for. There was no comparison to other (in my opinion superior) methods and tools. Instead of buying this book I would recommend you to buy an established book on real time systems and an established book on OO. You will end up spending less money and get a better overview of the two fields by reading fewer pages. Help other customers find the most helpful reviews  Was this review helpful to you?  Report abuse | Permalink  Comment 14 of 16 people found the following review helpful A must read for anyone working in real-time embedded, July 12, 1999 By A Customer This review is from: Doing Hard Time: Developing Real-Time Systems with UML, Objects, Frameworks, and Patterns (Hardcover) Wow! And I thought Real-Time UML was good! Doing Hard Time is everything Real-Time UML is plus so much more. I really liked the easy-to-read but in-depth coverage of the "hard stuff" of real-time and embedded systems. What's special about this book: The coverage of safety critical systems is unparalleled -- safety explained in terms of design patterns and key concepts and how to do this using object methods. The development process in Chapter 4 on ROPES shows how to effectively apply UML to think about, design and construct real-time systems. Chapter 11 explains the difficult concepts of timeliness and gives ways to guarantee schedulability. I've looked at other books on that topic and they're filled with really ugly math which makes for a difficult read. This book explains those concepts in an easy going way. The chapters on behavioral patterns covers "design patterns" for wiring together state machines to solve commonly occurring behavioral issues. I... Read more Help other customers find the most helpful reviews  Was this review helpful to you?  Report abuse | Permalink  Comment

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Praise For Doing Hard Time: Developing Real-Time Systems with UML, Objects, Frameworks, and Patterns

"This book will almost certainly become a seminal work in this field...the one book everyone will want to have both as a tutorial and as a reference." - Larry McAlister, Senior Systems Architect, ENSCO, Inc.

"Because in times past I had been a bit-bashing coder of real-time programs in assembly language for pokey little microprocessors, I was very skeptical when I first heard about UML -- skeptical but intrigued. The idea that you could “draw” real-time programs using “bubble charts” seemed ludicrous to me. I considered bubble charts good only for sketching out simple algorithms. I did not believe they could handle a real, complex software system.

To test my prejudging, I obtained and studied Douglass’ book. And as much as it pains me to admit that I was wrong, I now believe that you can indeed draw robust, complex, real-time software systems using Douglass’ methods and the I-Logix Rhapsody program (a demo disk is included with the book). First of all, to paraphrase the Buick commercial, I-Logix’ directed graphs are NOT your father’s bubble charts. They are significantly enhanced beyond the classical Mealy and Moore state machines with more optional ways to execute things as well as branching and memory constructs. In addition to the directed graphs, numerous other visual tools are presented.

The book describes, in detail, a comprehensive and careful software-design methodology for top-down design of complex software systems. While many in the software field have a penchant for inventing new words or using ordinary words in peculiar ways -- “dereference” and “parameter” comes to mind -- Douglass is careful to define all his terms. Like the blind wise men examining the elephant, many different ways to view such a system exist. Douglass steps through the visual tools used for each of these views, delineating their usefulness.

Visual tools are important because engineers are characterized by having high visual intelligence. They express themselves visually. They absorb information visually. Perceptual psychologists have discovered, unfortunately, that high visual intelligence correlates strongly with mild-to-severe dyslexia. So moving away from textual programming systems to a visual programming system is probably a very good idea for engineers.

Lastly, one salient aspect of the book has to be mentioned: the high quality of the writing. I have been editing the writing of engineers and programmers for twenty years now. The AQL of their writing is, in a word, wretched. Douglass’ prose, on the other hand, is clear, well organized, interesting, and entertaining. There is not a hint of Technical Manual English - a subset of English that is even more horrible than Business English or (UGH!) Marketing English."- Charles H Small, Senior Technical Editor at Electronic Systems magazine

Table of Contents

(Chapters begin with an Introduction and conclude with a Summary, Looking Ahead, Exercises and References.)

Figure List.


About the Author.


Preface.


Acknowledgments.

SECTION 1: BASICS.

SECTION 2: ANALYSIS.

SECTION 3: DESIGN.

SECTION 4. ADVANCED REAL-TIME MODELING.

Preface

Goals

Today's world literally runs on embedded computers. Virtually every field of endeavor in our modern society depends on embedded computers from manufacturing to transportation to medicine. The typical household is a computing eco-system that includes telephones, televisions, washing machines, ovens, and a host of other silicon-based fauna. Many, if not most, of these computing devices have timeliness requirements to their functionality, so that late action is often wrong action. Many embedded devices have the capacity to do great harm if they malfunction or fail.

Not only are more things being handled by embedded computing devices, but the scope, complexity, and criticality of the things being handled is increasing geometrically. Technological advances are crucial in order to keep up with the increasing demands on the developer of such systems. Gone are the days when the hardware complexity was the limiting factor in the development of electrical devices. Most companies involved in the manufacture of real-time and embedded systems have realized the truism of "the tail that wags the dog" and have begun seriously looking at ways to improve software productivity. These better ways to develop real-time and embedded systems are the source and soul of this book.

Doing Hard Time: Designing and Implementing Embedded Systems with UML focuses on model-based development of real-time and embedded systems using the Unified Modified Language (UML) and a risk-based iterative development lifecycle called ROPES. UML is a 3rd generation modeling language that rigorously defines the semantics of the object metamodel and provided a notation for capturing and communicating object structure and behavior. The UML became a standard modeling language in the OMG in late 1996, and the author remains heavily involved in its ongoing effort. This book is based upon the 1.3 revision of the UML standard.

Model-based development is crucial in today's high-complexity, short-development-cycle business environment. It is important to focus on the fundamental abstractions of the problem rather than on the low-level details of its implementation; to focus on "should the control rods be in the reactor core to avoid a meltdown?" rather than "should I jump on non-zero or carry?" By increasing the level of abstraction, it is possible to build more complex systems with fewer defects in less time--a winning combination for everyone concerned.

Because the UML is executable, it is possible to automatically generate executable systems from UML models. The importance of this goes well beyond simply saving the time and effort of hand-translating code from abstract models. It is an enabling technology, allowing the developer to rapidly move from the inception of a concept to the testing of that concept. This allows early risk reduction and encourages exploration of the solution space. Conceptual defects can be identified and fixed very early before many dependencies on the flawed concepts are created, resulting in higher-quality systems in less calendar time.

This book is meant to be a fusion of a number of subject domains almost universally left disjoint--real-time concepts such as timeliness and performance, object modeling, a rapid development process, and system safety. This unified approach allows the developer to follow simple and well-understood process steps culminating with the delivery of correct and timely embedded solutions.

There are very few books on using objects in real-time systems and even fewer that use the latest in object modeling languages--the UML. Virtually all object-oriented books focus primarily on business or data base application domains and do not mention real-time aspects at all. On the other hand, texts on real-time systems have largely ignored object-oriented methods. For the most part, such books fall into two primary camps: those that bypass methodological considerations altogether and focus solely on "bare metal" programming and those that are highly theoretical with little advice for actually implementing workable systems. Doing Hard Time is meant to bridge for these technologies, presenting the development of deployable real-time systems using the object semantics and notation of the UML. It does so in a tool-independent manner, even though it does use a particular tool to demonstrate the examples.

Audience

The book is oriented towards the practicing professional software developer and the computer science major, in the junior year or higher. The book could serve as an undergraduate or graduate level text, but the focus is on practical development rather than a theoretical introduction. A few equations are to be found in this book, but more theoretical and mathematical approaches are referenced where appropriate. The book assumes a reasonable proficiency in at least one programming language and at least a cursory exposure to the fundamental concepts of both object orientation and real-time systems.

Organization

This book is organized into 5 sections:

• The Basics

• Analysis

• Design

• Advanced Real-Time Modeling

• Appendices

1. UML Notational Guide: A short guide to the notations used in the UML and in the book.
2. Introduction to Rhapsody: An introduction to the UML visual programming tool provided in the accompanying CD-ROM.
3. Introduction to TimeWiz: An introduction to the schedulability analysis tool provided in the accompanying CD-ROM.

CD-ROM

The CD-ROM provided with this book contains three kinds of things:

• The examples presented within the pages of the book

• Rhapsody

• TimeWiz

I believe (and hope) that the needs of both the student and professional developer will be addressed by this book, and it is in this spirit that I offer it.

Acknowledgments

I wish to express thanks to my reviewers who tried hard to keep me honest and on topic, and who, I think, more or less succeeded:

Eran Gery, i-Logix

Jim Collins, i-Logix

Larry McAlister, ENSCO, Inc.

Therese M. Douglass, Air Traffic Software Architecture, Inc.

Gary Cernosek, Rational Software Corp.

I would also like to thank Neeraj Chandra and Gene Robinson of i-Logix for their support in allowing me to spend so much effort on this book, Doug Jensen of Mitre for his input on schedulability, Therese Douglass for her expertise in air traffic control systems, and the editorial team at Addison-Wesley, including Carter Shanklin, Krysia Bebick, and Maureen Willard, to name a few.