说明：  讲述了MMU地址映射机制，并且阐述了ARM架构下MMU机制和PowerPC下的MMU机制，并且详细讲述了VxWorrks系统下的MMU地址映射机制、物理内存、虚拟内存的管理等等，是学习虚拟内存和物理内存映射的很好资料。 已通过测试。
(About the MMU address mapping mechanism, and described the mechanism of the ARM architecture MMU mechanisms and PowerPC MMU, and a detailed account of the MMU address mapping mechanism VxWorrks system, physical memory, virtual memory management, etc., is to learn from the virtual memory and physical memory mapping of good information. Has been tested.)