Operating systems are an essential part of any computer system. Similarly, a course on operating systems is an essential part of any computer science education. This field is undergoing rapid change, as computers are now prevalent in virtually every arena of day-to-day life—from embedded devices in automobiles through the most sophisticated planning tools for governments and multinational firms. Yet the fundamental concepts remain fairly clear, and it is on these that we base this book.
We wrote this book as a text for an introductory course in operating systems at the junior or senior undergraduate level or at the first-year graduate level. We hope that practitioners will also find it useful. It provides a clear description of the concepts that underlie operating systems. As prerequisites, we assume that the reader is familiar with basic data structures, computer organization, and a high-level language, such as C or Java. The hardware topics required for an understanding of operating systems are covered in Chapter 1. In that chapter, we also include an overview of the fundamental data structures that are prevalent in most operating systems. For code examples, we use predominantly C, with some Java, but the reader can still understand the algorithms without a thorough knowledge of these languages.
Concepts are presented using intuitive descriptions. Important theoretical results are covered, but formal proofs are largely omitted. The bibliographical notes at the end of each chapter contain pointers to research papers in which results were first presented and proved, as well as references to recent material for further reading. In place of proofs, figures and examples are used to suggest why we should expect the result in question to be true.
The fundamental concepts and algorithms covered in the book are often based on those used in both commercial and open-source operating systems. Our aim is to present these concepts and algorithms in a general setting that is not tied to one particular operating system. However, we present a large number of examples that pertain to the most popular and the most innovative operating systems, including Linux, Microsoft Windows, Apple Mac OS X, and Solaris. We also include examples of both Android and iOS, currently the two dominant mobile operating systems.
The organization of the text reflects our many years of teaching courses on operating systems, as well as curriculum guidelines published by the IEEE Computing Society and the Association for Computing Machinery (ACM). Consideration was also given to the feedback provided by the reviewers of the text, along with the many comments and suggestions we received from readers of our previous editions and from our current and former students.
The text is organized in six major parts:
We have based Operating System Essentials on the Ninth Edition of Operating System Concepts, published in 2012. Our intention behind developing this Essentials edition is to provide readers with a textbook that focuses on the core concepts that underlie contemporary operating systems. By focusing on core concepts, we believe students are able to grasp the essential features of a modern operating system more easily and more quickly.
To achieve this, Operating System Essentials omits the following coverage from the Ninth Edition of Operating System Concepts:
For those that wish to pursue a more comprehensive study of operating systems, we refer you to the Ninth Edition of Operating System Concepts, and in the following we describe the changes relevant to that edition.
As we wrote this Second Edition of Operating System Concepts Essentials, we were guided by the recent growth in the following fundamental areas that affect operating systems:
We have integrated relevant coverage throughout this new edition To emphasize these topics. Additionally, we have rewritten material in almost every chapter by bringing older material up to date and removing material that is no longer interesting or relevant.
We have also made substantial organizational changes. For example, we have eliminated the chapter on real-time systems and instead have integrated appropriate coverage of these systems throughout the text. We have reordered the chapters on storage management and have moved up the presentation of process synchronization so that it appears before process scheduling. Most of these organizational changes are based on our experiences while teaching courses on operating systems.
Below, we provide a brief outline of the major changes to the various chapters:
This book uses examples of many real-world operating systems to illustrate fundamental operating-system concepts. Particular attention is paid to Linux and Microsoft Windows, but we also refer to various versions of UNIX (including Solaris, BSD, and Mac OS X).
The text also provides several example programs written in C and Java. These programs are intended to run in the following programming environments:
We have chosen these three programming environments because we believe that they best represent the two most popular operating-system models—Windows and UNIX/Linux—along with the widely used Java environment. Most programming examples are written in C, and we expect readers to be comfortable with this language. Readers familiar with both the C and Java languages should easily understand most programs provided in this text.
In some instances—such as thread creation—we illustrate a specific concept using all three programming environments, allowing the reader to contrast the three different libraries as they address the same task. In other situations, we may use just one of the APIs to demonstrate a concept. For example, we illustrate shared memory using just the POSIX API; socket programming in TCP/IP is highlighted using the Java API.
To help students gain a better understanding of the Linux system, we provide a Linux virtual machine, including the Linux source code, that is available for download from the website supporting this text (http://www.os-book.com). This virtual machine also includes a gcc development environment with compilers and editors. Most of the programming assignments in the book can be completed on this virtual machine, with the exception of assignments that require Java or the Windows API.
We also provide three programming assignments that modify the Linux kernel through kernel modules:
Over time it is our intention to add additional kernel module assignments on the supporting website.
When you visit the website supporting this text at http://www.os-book.com, you can download the following resources:
On the website for this text, we provide several sample syllabi that suggest various approaches for using the text in both introductory and advanced courses. As a general rule, we encourage instructors to progress sequentially through the chapters, as this strategy provides the most thorough study of operating systems. However, by using the sample syllabi, an instructor can select a different ordering of chapters (or subsections of chapters).
In this edition, we have added over sixty new written exercises and over twenty new programming problems and projects. Most of the new programming assignments involve processes, threads, process synchronization, and memory management. Some involve adding kernel modules to the Linux system which requires using either the Linux virtual machine that accompanies this text or another suitable Linux distribution.
Solutions to review questions, written exercises and programming assignments are available to instructors who have adopted this text for their operating-system class. To obtain these restricted supplements, contact your local John Wiley & Sons sales representative. You can find your Wiley representative by going to http://www.wiley.com/college and clicking “Who's my rep?”
We encourage you to take advantage of the review questions (available online) and practice exercises that appear at the end of each chapter. The review questions as well as solutions to the practice exercises are available for download from the supporting website http://www.os-book.com. We also encourage you to read through the study guide, which was prepared by one of our students. Finally, for students who are unfamiliar with UNIX and Linux systems, we recommend that you download and install the Linux virtual machine that we include on the supporting website. Not only will this provide you with a new computing experience, but the open-source nature of Linux will allow you to easily examine the inner details of this popular operating system.
We wish you the very best of luck in your study of operating systems.
We have endeavored to eliminate typos, bugs, and the like from the text. But, as in new releases of software, bugs almost surely remain. An up-to-date errata list is accessible from the book's website. We would be grateful if you would notify us of any errors or omissions in the book that are not on the current list of errata.
We would be glad to receive suggestions on improvements to the book. We also welcome any contributions to the book website that could be of use to other readers, such as programming exercises, project suggestions, on-line labs and tutorials, and teaching tips. E-mail should be addressed to [email protected].
This book is derived from the previous editions, the first three of which were coauthored by James Peterson. Others who helped us with previous editions include Hamid Arabnia, Rida Bazzi, Randy Bentson, David Black, Joseph Boykin, Jeff Brumfield, Gael Buckley, Roy Campbell, P. C. Capon, John Carpenter, Gil Carrick, Thomas Casavant, Bart Childs, Ajoy Kumar Datta, Joe Deck, Sudarshan K. Dhall, Thomas Doeppner, Caleb Drake, M. Racsit Eskicioğlu, Hans Flack, Robert Fowler, G. Scott Graham, Richard Guy, Max Hailperin, Rebecca Hartman, Wayne Hathaway, Christopher Haynes, Don Heller, Bruce Hillyer, Mark Holliday, Dean Hougen, Michael Huang, Ahmed Kamel, Morty Kewstel, Richard Kieburtz, Carol Kroll, Morty Kwestel, Thomas LeBlanc, John Leggett, Jerrold Leichter, Ted Leung, Gary Lippman, Carolyn Miller, Michael Molloy, Euripides Montagne, Yoichi Muraoka, Jim M. Ng, Banu Özden, Ed Posnak, Boris Putanec, Charles Qualline, John Quarterman, Mike Reiter, Gustavo Rodriguez-Rivera, Carolyn J. C. Schauble, Thomas P. Skinner, Yannis Smaragdakis, Jesse St. Laurent, John Stankovic, Adam Stauffer, Steven Stepanek, John Sterling, Hal Stern, Louis Stevens, Pete Thomas, David Umbaugh, Steve Vinoski, Tommy Wagner, Larry L. Wear, John Werth, James M. Westall, J. S. Weston, and Yang Xiang
Robert Love updated both Chapter 15 and the Linux coverage throughout the text, as well as answering many of our Android-related questions. Jonathan Katz contributed to Chapter 14. Salahuddin Khan updated Section 14.9 to provide new coverage of Windows 7 security.
Chapter 15 was derived from an unpublished manuscript by Stephen Tweedie. Cliff Martin helped with updating the UNIX appendix to cover FreeBSD. Some of the exercises and accompanying solutions were supplied by Arvind Krishnamurthy. Andrew DeNicola prepared the student study guide that is available on our website. Some of the slides were prepeared by Marilyn Turnamian.
Mike Shapiro, Bryan Cantrill, and Jim Mauro answered several Solaris-related questions, and Bryan Cantrill from Sun Microsystems helped with the ZFS coverage. Josh Dees and Rob Reynolds contributed coverage of Microsoft's NET. The project for POSIX message queues was contributed by John Trono of Saint Michael's College in Colchester, Vermont.
Judi Paige helped with generating figures and presentation of slides. Thomas Gagne prepared new artwork for this edition. Mark Wogahn has made sure that the software to produce this book ( and fonts) works properly. Ranjan Kumar Meher rewrote some of the software used in the production of this new text.
Our Executive Editor, Beth Lang Golub, provided expert guidance as we prepared this edition. She was assisted by Katherine Willis, who managed many details of the project smoothly. The Senior Production Editor, Joyce Poh, was instrumental in handling all the production details.
The cover illustrator was Susan Cyr, and the cover designer was Madelyn Lesure. Beverly Peavler copy-edited the manuscript. The freelance proofreader was Katrina Avery; the freelance indexer was WordCo, Inc.
Abraham Silberschatz, New Haven, CT, 2013
Peter Baer Galvin, Boston, MA, 2013
Greg Gagne, Salt Lake City, UT, 2013