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Press Release: January 16, 2003

O'Reilly Authors Reveal the Inner Workings of the Linux Kernel: O'Reilly Releases "Understanding the Linux Kernel, Second Edition"

Sebastopol, CA--To thoroughly understand what makes Linux tick and why it's so efficient, one needs to delve deep into the heart of the operating system--into the Linux kernel itself. The kernel is Linux--in the case of the Linux operating system, it's the only bit of software to which the term "Linux" applies. The kernel handles all the requests or completed I/O operations and determines which programs will share its processing time, and in what order. Responsible for the sophisticated memory management of the whole system, the Linux kernel is the force behind the legendary Linux efficiency.

Understanding the Linux Kernel, Second Edition by Daniel P. Bovet and Marco Cesati (O'Reilly, US $49.95) takes readers on a guided tour through the most significant data structures, many algorithms, and programming tricks used in the kernel. Probing beyond the superficial features, the authors offer valuable insights to people who want to know how things really work inside their machine. Relevant segments of code are dissected and discussed line by line. The book covers more than just the functioning of the code, it explains the theoretical underpinnings of why Linux does things the way it does.

The new edition of "Understanding the Linux Kernel" has been updated to cover version 2.4 of the kernel, which is quite different from version 2.2: the virtual memory system is entirely new, support for multiprocessor systems is improved, and whole new classes of hardware devices have been added.

"The kernel code has been significantly enlarged," Bovet and Cesati explain. "The 2.2 version occupies about 58 megabytes of disk space, while the 2.4 version occupies about 144 megabytes. In order to list all of the code of the 2.4 version, we would need more than forty books like 'Understanding the Linux Kernel,' without commenting on it!" While refraining from listing all the code, the authors explore each significant new feature in detail. Other topics in the book include:

  • Memory management including file buffering, process swapping, and Direct Memory Access (DMA)
  • The Virtual Filesystem and the Second Extended Filesystem
  • Process creation and scheduling
  • Signals, interrupts, and the essential interfaces to device drivers
  • Timing
  • Synchronization in the kernel
  • Interprocess Communication (IPC)
  • Program execution

The second edition of "Understanding the Linux Kernel" will acquaint readers with all the inner workings of Linux, but is more than just an academic exercise. Readers will learn what conditions bring out Linux's best performance, and see how it meets the challenge of providing good system response during process scheduling, file access, and memory management in a wide variety of environments. If knowledge is indeed power, then this book give Linux users the power to make the most of their Linux systems.

What the critics said about the first edition:

"This is a good book. The authors have cracked open a large collection of code that's currently very relevant. If they are in for the long haul and release revised books in a timely way, then this will likely become and remain the definitive explanation of Linux internals."
--John Regehr,, January 2001

"After reading this book, you should be able to find your way through the code, distinguishing between crucial data structures and secondary ones--in short, you'll become a true Linux hacker."
--Software World, January 2001

"An outstanding explanation of the kernel that should benefit almost any C/C++ programmer working on Linux. Any programmer who has jumped into the kernel knows there is a real need for a book that takes a reader by the hand and steps through all the major (and sometime minor) internal components and processes of the Linux kernel. Luckily 'Understanding the Linux Kernel' not only does that, but it does it very well...the presentation of the material is very well executed, even by O'Reilly's normally high standards...a must-read for anyone doing non-trivial programming on Linux."
--Lou Grinzo,, December 22, 2000

"If you have reached the point where you have learned a few simple ideas about programming in Linux and you would like to know more about kernels, then this book is probably for you."
--Richard Ibbotson, Sheffield Linux User's Group, February 2001

"I am impressed both by the depth of coverage and by the readability of the text, especially bearing in mind the somewhat geek-like nature of the subject that's being discussed. It's the best explanation of Linux kernel internals that I've seen so far. This one's sure to be a classic, buy it if you can."
--Developers Review, February 2001

"A practical introduction to kernel internals for those who are new to the subject, and I strongly recommend it for any programmer who's competent in C.", February 14th, 2001

Additional Resources:

Understanding the Linux Kernel, Second Edition
Daniel P. Bovet & Marco Cesati
ISBN 0-596-00213-0, 765 pages, $49.95 (US), $77.95 (CAN), 35.50 (UK)
1-800-998-9938; 1-707-827-7000

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