Memory Addressing （一）

Chapter 2. Memory Addressing

This chapter deals with addressing techniques. Luckily, an operating system is not forced to keep track of physical memory all by itself; today's microprocessors include several hardware circuits to make memory management both more efficient and more robust so that programming errors cannot cause improper accesses to memory outside the program.

这一章讨论内存映射技术。幸运的是，OS不用自己管理物理内存；如今的微处理器都包含了相应的硬件电路，内存管理变得更加有效率、更加健壮，有意或者无意的程序错误不可能访问到不该访问的内存。

CPU都有MMU单元，OS只需要控制好MMU就行了。

As in the rest of this book, we offer details in this chapter on how 80x86 microprocessors address memory chips and how Linux uses the available addressing circuits. You will find, we hope, that when you learn the implementation details on Linux's most popular platform you will better understand both the general theory of paging and how to research the implementation on other platforms.

学习内容:x86地址映射、Linux如何使用这些特性、Linux的page技术、其他平台的实现。

This is the first of three chapters related to memory management; Chapter 8 discusses how the kernel allocates main memory to itself, while Chapter 9 considers how linear addresses are assigned to processes.

第八章会讨论Kernel如何分配main memory给它本身，第九章会涉及线性地址如何assign给进程。