This book is about the concept, structure, and mechanisms of operating systems. Its purpose is to present, as clearly and completely as possible, the nature and characteristics of modern-day operating systems.This task is challenging for several reasons. First, there is tremendous range and variety of computer systems for which operating systems are designed. These include embedded systems, smart phones, single-user workstations and personal computers, medium-sized share systems, large mainframe and supercomputers, and specialized machines such as real-time systems. The variety is not just in the capacity and speed of machines, but in applications and system support requirements as well. Second, the rapid pace of change that has always characterized computer systems continues with no letup. A number of key areas in operating system design are of recent origin, and research into these and other new areas continues. In spite of this variety and pace of change, certain fundamentals concept apply consistenly throughout. This book is organized in eight part. Part One Background, Part Two Processes, Part Three Memory, Part Four Scheduling, Part Five Input/Output and File, Part Six Embedded Systems, Part Seven Security, and Part Eight Distributed Systems.//yeni