This revised and updated Second Edition presents a practical introduction to operating systems and illustrates these principles through a hands-on approach using accompanying simulation models developed in Java and C++. This text is appropriate for upper-level undergraduate courses in computer science. Case studies throughout the text feature the implementation of Java and C++ simulation models, giving students a thorough look at both the theoretical and the practical concepts discussed in modern OS courses. This pedagogical approach is designed to present a clearer, more practical look at OS concepts, techniques, and methods without sacrificing the theoretical rigor that is necessary at this level. It is an ideal choice for those interested in gaining comprehensive, hands-on experience using the modern techniques and methods necessary for working with these complex systems.New material added to the Second Edition:- Chapter 11 (Security) has been revised to include the most up-to-date information- Chapter 12 (Firewalls and Network Security) has been updated to include material on middleware that allows applications on separate machines to communicate (e.g. RMI, COM+, and Object Broker)- Includes a new chapter dedicated to Virtual Machines- Provides introductions to various types of scams- Updated to include information on Windows 7 and Mac OS X throughout the text- Contains new material on basic hardware architecture that operating systems depend on- Includes new material on handling multi-core CPUs