We would like to thank each of our technical reviewers for their time and careful thought. Their suggestions have made this book stronger. Particular thanks go to Linus Torvalds, Alan Cox, Ted Ts'o, and Arjan van de Ven, who took time to answer our questions.
After supporting us through writing the first edition, our wives, Kim Johnson and Brigid Troan, were so brave and generous that they encouraged us to write this second edition. Without their help, this book would never have been written, let alone updated.