作者：华清远见嵌入式学院。《Linux设备驱动开发详解》（08&09年度畅销榜TOP50）第11章、内存与I/O访问。由于Linux系统中提供了复杂的内存管理功能，所以内存的概念在Linux系统中变得相对复杂，出现了常规内存、高端内存、虚拟地址、逻辑地址、总线地址、物理地址、I/O内存、设备内存、预留内存等概念。本章将系统地讲解内存和I/O的访问编程，带您走出内存和I/O的概念迷宫。11.1节讲解内存和I/O的硬件机制，主要涉及内存空间、I/O空间和MMU。11.2节讲解Linux的内存管理、内存区域的分布、常规内存与高端内存的区别。11.3节讲解Linux内存存取的方法，主要涉及内存动态申请以及通过虚拟地址存取物理地址的方法。11.4节讲解设备I/O内存和I/O端口的访问流程，这一节对于编写设备驱动意义非常重大，设备驱动使用此节的方法访问物理设备。11.5节讲解设备驱动中的DMA与CACHE一致性问题以及DMA编程方法。-Author: HuaQing vision embedded institute. The Linux device driver development "(08 and 09 sep TOP50) annual list of best-selling chapter 11, the memory and I/O visit. Because of the complex Linux system provide the memory management function, so the concept of memory in Linux systems become relatively complex, the emergence of a conventional memory, the high memory, virtual address, logical address, bus address, physical address, I/O memory, equipment memory, obligate concepts such as memory. This chapter will systematically explaining memory and I/O visit programming, take you out of memory and I/O concept maze. Section 11.1 explain memory and I/O hardware mechanism, mainly involves the memory space, I/O space and MMU. Section 11.2 explain the Linux memory management, memory area distribution, conventional memory and the high memory difference. Section 11.3 memory access method explained Linux, Lord ?