A very good book for those who want to learn advanced concepts in OS. Since it is a open source the book is very useful in understanding how they look like. The paper quality is too good, which makes u read non stop. i luv reading this book. Price worth it. A good buy.

Before I encountered this book it was quite a bit of frustration in attempt to learn BSD and UNIX to the point I can really use it. For some reason there so many good books in a subject with one of two inclinations: or the book is too theoretical and very little of the real workflow provided or it is too down to earth and it is difficult to understand what is behind the sophisticated command line zingers.
I found this book to be well balanced, well written and generally providing good, accessible way to get into BSD. I have followed advise in someone's review here and coupled this book with Linux and UNIX for a beginner training suite, 4DVDs + 2CDs includes 4 Unix Academy Certifications ed.2008. To my great surprise I have to say they really have made an outstanding training outfit!
If you really ready for a training and do not expect that UNIX will come to you overnight it is worthy book and deserves your attention.

First of all you should be warned that this is not an introduction to get started with UNIX kernel programming. The Design of the UNIX Operating System by M.J. Bach provides a good general introduction to UNIX kernel programming. The design and implementation of the FreeBSD operating system is an excellent book to deepen knowledge of the UNIX kernel by looking how a current UNIX is implemented in practice. Even if you plan to write code for another kernel, working through the FreeBSD kernel with this book as a guide is a good excercise to become consious of the fundamental problems and solutions in kernel design. FreeBSD (or any of the other BSDs) is a good starting point, because the BSDs have relatively stable kernel subsystems and APIs due to the long cycles in BSD development.

The writing style of the authors is to the point (don't expect a novel) and clear. The troff typesetting of the book gives it a consistent style and simple, but clear diagrams (though I heard that some diagrams were hand-drawn). The book doesn't just drop the reader in a kernel subsystem. The second chapter gives a detailed explanation of the various kernel subsystems, and the relation between the subsystems. The third chapter gives a summary of what is expected from a kernel from the user level. Combined these two chapters give the reader the necessary conception of the FreeBSD kernel to start looking at individual parts of the kernel in detail. Most remaining chapters are logically ordered, in that subsystems are ordered from parts with less dependencies to parts with more dependencies (e.g. memory management and I/O are covered before filesystems).

If you are interested in UNIX programming, you should have this book on your bookshelf (as well as a CVS checkout of the FreeBSD kernel tree to read the implementation).

A BSD Bible. I never could read the Bible. I do Believe ...

650+ pages of truth and gore. I (as a sysadmin and BSD boomer) related most to the History (Ch.1) and Startup/Shutdown (final Ch.14). Memory management and other gore escapes me. GOOD JOB!

For the other side of the story, you may wish to check out the most recent "Inside Microsoft Windows" or "Microsoft Windows Internals" by Mark Russinovich.