以下、引用
Provides you with a top down view of OS X and iOS
Walks you through the phases of system startup—both Mac (EFi) and mobile (iBoot)
Explains how processes, threads, virtual memory, and filesystems are maintained
Covers the security architecture
Reviews the internal Apis used by the system—BSD and Mach
Dissects the kernel, XNU, into its sub components: Mach, the BSD Layer, and I/o kit, and explains each in detail
Explains the inner workings of device drivers