This text demystifies the subject by using a simple and step-by-step approach, from fundamental to advanced concepts of operating systems. Its primary objective is to provide a reasonable balance between theoretical concepts and practical implementation, while projecting an insight into the generic operating systems of today. It addresses most of the issues that need to be resolved in the design of operating systems and describes successful approaches in the form of abstract models and algorithms. Key Features — Exhaustive discussion on conventional uniprocessor-based generic operating systems — Separate chapters on Distributed Systems and Real Time Operating Systems — Separate chapter on security aspects — Elaborate description of numerous design issues — More than 350 figures and tables that address various categories of operating systems in detail