This "Nutshell" reference documents the features of the Linux 2.6 kernel in detail so that system administrators and developers can customize and optimize their systems for better performance. An operating system's kernel handles all interactions between the CPU and the external world, and determines which programs will share processor time, in what order. This in-depth reference documents Version 2.6 of the Linux kernel, which has seen significant changes to nearly every kernel subsystem, particularly in the areas of memory management and block devices. "Linux Kernel in a Nutshell" explains the conditions that bring out Linux's best performance, and how the OS meets the challenge of providing good system response during process scheduling, file access, and memory management in a wide variety of environments.