To make the computer system convenient for users, the operating system provides a uniform, logical view of information storage. The operating system abstracts from the physical properties of its storage devices to define a logical storage unit, the file. The operating system maps files onto physical media and accesses these files via the storage devices.
File System Management
File management is one of the most visible components of an operating system. Computers can store information on several different types of physical media. Magnetic disk, optical disk, and magnetic tape are the most common. Each of these media has its own characteristics and physical organization. Each medium is controlled by a device, such as a disk drive or tape drive, that has its own characteristics. These properties include access speed, capacity, data-transfer rate, and access method (sequential or random).
A file is a collection of related information defined by its creator. Commonly, files represent programs (both source and object forms) and data. data files may be alphanumeric, or binary. Files may be free-form (for example, text files), or they may be formatted rigidly (for example, fixed fields). Clearly, the concept of a file is an extremely general one.
The operating system implements the abstract concept of a file by managing mass-storage media, such as tapes and disks, and the devices that control them. In addition, files are normally organized into directories to make them easier to use. Finally, when multiple users have access to files, it may be desirable to control which user may access a file and how that user may access it (for example, read write, append).
The operating system is responsible for the following activities in connection with file management:
• Creating and deleting files
• Creating and deleting directories to organize files
• Supporting primitive for manipulating files and directories
• Mapping files onto secondary storage
• Backing up files on stable (nonvolatile) storage media
About the Authors
Abraham Silberschatz is the Sidney J. Weinberg Professor of Computer Science at Yale University. Prior to joining Yale, he was the Vice President of the Information Sciences Research Center at Bell Laboratories. Prior to that, he held a chaired professorship in the Department of Computer Sciences at the University of Texas at Austin.
Professor Silberschatz is a Fellow of the Association of Computing Machinery (ACM), a Fellow of Institute of Electrical and Electronic Engineers (IEEE), a Fellow of the American Association for the Advancement of Science (AAAS), and a member of the Connecticut Academy of Science and Engineering.
Greg Gagne is chair of the Computer Science department at Westminster College in Salt Lake City where he has been teaching since 1990. In addition to teaching operating systems, he also teaches computer networks, parallel programming, and software engineering.
Operating System Concepts, now in its ninth edition, continues to provide a solid theoretical foundation for understanding operating systems. The ninth edition has been thoroughly updated to include contemporary examples of how operating systems function. The text includes content to bridge the gap between concepts and actual implementations. End-of-chapter problems, exercises, review questions, and programming exercises help to further reinforce important concepts. A new Virtual Machine provides interactive exercises to help engage students with the material.
Reader Adam Sinclair says, "
I'm writing this review from the perspective of a student. I am finishing an Operating Systems course at university and I have to say this book is fantastic at introducing new concepts. If there is ever a conversation about OS, I always refer to this book. The content is very well laid out and organized in a way that can be read from beginning to end. There is no need to jump from one chapter to another (unless you want to skip sections)."
Reader Chetan Sharma says, "
This book is bible for operating system knowledge. It covers very important concepts of Process Management and Memory Management. This book is good for all type of readers - Beginner, Intermediate and Advanced reader. Highly recommended for Students/Professionals/Readers who want to enhance their knowledge.
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