For a one-semester undergraduate course in operating systems for computer science, computer engineering, and electrical engineering majors. Operating Systems: Internals and Design Principles is a comprehensive and unified introduction to operating systems. By using several innovative tools, Stallings makes it possible to understand critical core concepts that can be fundamentally challenging. The new edition includes the implementation of web based animations to aid visual learners. At key points in the book, students are directed to view an animation and then are provided with assignments to alter the animation input and analyze the results. The concepts are then enhanced and supported by end-of-chapter case studies of UNIX, Linux and Windows Vista. These provide students with a solid understanding of the key mechanisms of modern operating systems and the types of design tradeoffs and decisions involved in OS design. Because they are embedded into the text as end of chapter material, students are able to apply them right at the point of discussion. This approach is equally useful as a basic reference and as an up-to-date survey of the state of the art. Resources William Stallings has prepared a robust suite of student and instructor resources, including a rich set of Animations to illustrate key functions and algorithms in OS design.  (Icons are placed at relevant points in the text to indicate that an animation is available.) Access them via the Prentice Hall page www.prenhall.com/stallings  or directly at the author's website http://www.williamstallings.com/OS/OS6e.html under the link "Useful Websites."  Visit Stalllings Computer Science Student Resource page at http://williamstallings.com/StudentSupport.html. Key downloadable instructor resources including access codes to GOAL (www.prenhall.com/goal), as well as student access to GOAL are available by clicking on the Resources tab above.