Operating Systems deals with the fundamental concepts and principles that govern the behavior of operating systems. Many issues regarding the structure of operating systems, including the problems of managing processes, processors, and memory, are examined. Various aspects of operating systems are also discussed, from input-output and files to security, protection, reliability, design methods, performance evaluation, and implementation methods. Comprised of 10 chapters, this volume begins with an overview of what constitutes an operating system, followed by a discussion on the definition and properties of the basic unit of computation within an operating system, the process. The reader is then introduced to processor allocation schemes as well as various classes of scheduling disciplines and their implementations; memory management functions; and virtual memory. Subsequent chapters focus on input-output and files; protection in an operating system; and design and implementation of an operating system. The book concludes by describing two operating systems to help the reader visualize how the major components of a system interact in a complete system: the Venus Operating System developed by MITRE Corp. and the SUE nucleus, designed at the University of Toronto. This monograph is intended for fourth-year undergraduates and first-year graduate students, as well as lecturers who plans to institute a course on operating systems.