What makes an operating system modern? According to author Andrew Tanenbaum, it is the awareness of high-demand computer applications--primarily in the areas of multimedia, parallel and distributed computing, and security. The development of faster and more advanced hardware has driven progress in software, including enhancements to the operating system. It is one thing to run an old operating system on current hardware, and another to effectively leverage current hardware to best serve modern software applications. If you don't believe it, install Windows 3.0 on a modern PC and try surfing the Internet or burning a CD.
Readers familiar with Tanenbaum's previous text, Operating Systems, know the author is a great proponent of simple design and hands-on experimentation. His earlier book came bundled with the source code for an operating system called Minux, a simple variant of Unix and the platform used by Linus Torvalds to develop Linux. Although this book does not come with any source code, he illustrates many of his points with code fragments (C, usually with Unix system calls).
The first half of Modern Operating Systems focuses on traditional operating systems concepts: processes, deadlocks, memory management, I/O, and file systems. There is nothing groundbreaking in these early chapters, but all topics are well covered, each including sections on current research and a set of student problems. It is enlightening to read Tanenbaum's explanations of the design decisions made by past operating systems gurus, including his view that additional research on the problem of deadlocks is impractical except for "keeping otherwise unemployed graph theorists off the streets."
It is the second half of the book that differentiates itself from older operating systems texts. Here, each chapter describes an element of what constitutes a modern operating system--awareness of multimedia applications, multiple processors, computer networks, and a high level of security. The chapter on multimedia functionality focuses on such features as handling massive files and providing video-on-demand. Included in the discussion on multiprocessor platforms are clustered computers and distributed computing. Finally, the importance of security is discussed--a lively enumeration of the scores of ways operating systems can be vulnerable to attack, from password security to computer viruses and Internet worms.
Included at the end of the book are case studies of two popular operating systems: Unix/Linux and Windows 2000. There is a bias toward the Unix/Linux approach, not surprising given the author's experience and academic bent, but this bias does not detract from Tanenbaum's analysis. Both operating systems are dissected, describing how each implements processes, file systems, memory management, and other operating system fundamentals.
Tanenbaum's mantra is simple, accessible operating system design. Given that modern operating systems have extensive features, he is forced to reconcile physical size with simplicity. Toward this end, he makes frequent references to the Frederick Brooks classic The Mythical Man-Month for wisdom on managing large, complex software development projects. He finds both Windows 2000 and Unix/Linux guilty of being too complicated--with a particular skewering of Windows 2000 and its "mammoth Win32 API." A primary culprit is the attempt to make operating systems more "user-friendly," which Tanenbaum views as an excuse for bloated code. The solution is to have smart people, the smallest possible team, and well-defined interactions between various operating systems components. Future operating system design will benefit if the advice in this book is taken to heart. --Pete Ostenson
From the Inside Flap
The world has changed a great deal since the first edition of this book appeared in 1992. Computer networks and distributed systems of all kinds have become very common. Small children now roam the Internet, where previously only computer professionals went. As a consequence, this book has changed a great deal, too.
The most obvious change is that the first edition was about half on single-processor operating systems and half on distributed systems. I chose that format in 1991 because few universities then had courses on distributed systems and whatever students learned about distributed systems had to be put into the operating systems course, for which this book was intended. Now most universities have a separate course on distributed systems, so it is not necessary to try to combine the two subjects into one course and one book. This book is intended for a first course on operating systems, and as such focuses mostly on traditional single-processor systems.
I have coauthored two other books on operating systems. This leads to two possible course sequences.
Operating Systems Design and Implementation by Tanenbaum and Woodhull Distributed Systems by Tanenbaum and Van Steen
Modern Operating Systems by Tanenbaum Distributed Systems by Tanenbaum and Van Steen
The former sequence uses MINIX and the students are expected to experiment with MINIX in an accompanying laboratory supplementing the first course. The latter sequence does not use MINIX. Instead, some small simulators are available that can be used for student exercises during a first course using this book. These simulators can be found starting on the author's Web page: cs.vu.nl/~ast/ by clicking on Software and supplementary material for my books.
In addition to the major change of switching the emphasis to single-processor operating systems in this book, other major changes include the addition of entire chapters on computer security, multimedia operating systems, and Windows 2000, all important and timely topics. In addition, a new and unique chapter on operating system design has been added.
Another new feature is that many chapters now have a section on research about the topic of the chapter. This is intended to introduce the reader to modern work in processes, memory management, and so on. These sections have numerous references to the current research literature for the interested reader. In addition, Chapter 13 has many introductory and tutorial references.
Finally, numerous topics have been added to this book or heavily revised. These topics include: graphical user interfaces, multiprocessor operating systems, power management for laptops, trusted systems, viruses, network terminals, CDROM file systems, mutexes, RAID, soft timers, stable storage, fair-share scheduling, and new paging algorithms. Many new problems have been added and old ones updated. The total number of problems now exceeds 450. A solutions manual is available to professors using this book in a course. They can obtain a copy from their local Prentice Hall representative. In addition, over 250 new references to the current literature have been added to bring the book up to date.
Despite the removal of more than 400 pages of old material, the book has increased in size due to the large amount of new material added. While the book is still suitable for a one-semester or two-quarter course, it is probably too long for a one-quarter or one-trimester course at most universities. For this reason, the book has been designed in a modular way. Any course on operating systems should cover chapters 1 through 6. This is basic material that every student show know.
If additional time is available, additional chapters can be covered. Each of them assumes the reader has finished chapters 1 through 6, but Chaps. 7 through 12 are each self contained, so any desired subset can be used and in any order, depending on the interests of the instructor. In the author's opinion, Chaps. 7 through 12 are much more interesting than the earlier ones. Instructors should tell their students that they have to eat their broccoli before they can have the double chocolate fudge cake dessert.
I would like to thank the following people for their help in reviewing parts of the manuscript: Rida Bazzi, Riccardo Bettati, Felipe Cabrera, Richard Chapman, John Connely, John Dickinson, John Elliott, Deborah Frincke, Chandana Gamage, Robbert Geist, David Golds, Jim Griffioen, Gary Harkin, Frans Kaashoek, Mukkai Krishnamoorthy, Monica Lam, Jussi Leiwo, Herb Mayer, Kirk McKusick, Evi Nemeth, Bill Potvin, Prasant Shenoy, Thomas Skinner, Xian-He Sun, William Terry, Robbert Van Renesse, and Maarten van Steen. Jamie Hanrahan, Mark Russinovich, and Dave Solomon were enormously knowledgeable about Windows 2000 and very helpful. Special thanks go to A1 Woodhull for valuable reviews and thinking of many new end-of-chapter problems.
My students were also helpful with comments and feedback, especially Staas de Jong, Jan de Vos, Niels Drost, David Fokkema, Auke Folkerts, Peter Groenewegen, Wilco Ibes, Stefan Jansen, Jeroen Ketema, Joeri Minder, Irwin Oppenheim, Stef Post, Umar Rehman, Daniel Rijkhof, Maarten Sander, Maurits van der Schee, Rik van der Stoel, Mark van Drill, Dennis van Veen, and Thomas Zeeman.
Barbara and Marvin are still wonderful, as usual, each in a unique way. Finally, last but not least, I would like to thank Suzanne for her love and patience, not to mention all the druiven and kersen, which have replaced the sinasappelsap in recent times.
Andrew S. Tanenbaum