chapter 2 SYSTEM ARCHITECTURE OVERVIEW

IA-32 architecture (beginning with the Intel386 processor family) provides extensive
support for operating-system and system-development software. This support offers
multiple modes of operation, which include:

ia-32框架（由intel386开始的处理器系列）提供了对操作系统和系统开发软件的广泛支持。这种支持

提供了多种操作模式其中包括
• Real mode, protected mode, virtual 8086 mode, and system management mode.
These are sometimes referred to as legacy modes.（遗产模式？什么意思不明白）
Intel 64 architecture supports almost all the system programming facilities available
in IA-32 architecture and extends them to a new operating mode (IA-32e mode) that
supports a 64-bit programming environment. IA-32e mode allows software to
operate in one of two sub-modes:

64位结构支持32为结构的操作模式而且还扩展出了新的操作模式IA-32e mode 
• 64-bit mode supports 64-bit OS and 64-bit applications
• Compatibility mode allows most legacy software to run; it co-exists with 64-bit
applications under a 64-bit OS.
The IA-32 system-level architecture and includes features to assist in the following
operations:
• Memory management
• Protection of software modules
• Multitasking
• Exception and interrupt handling
• Multiprocessing
• Cache management
• Hardware resource and power management
• Debugging and performance monitoring

Ia-32系统级结构极其特性支持以下的操作

内存的管理

软件模型的保护（不太明白什么意思）

多任务

异常和中断的处理

多线程

缓存的管理

硬件资源和电源的管理

调试和性能的监控
This chapter provides a description of each part of this architecture. It also describes
the system registers that are used to set up and control the processor at the system
level and gives a brief overview of the processor’s system-level (operating system)
instructions.

不翻译了
Many features of the system-level architectural are used only by system programmers.
However, application programmers may need to read this chapter and the
following chapters in order to create a reliable and secure environment for application
programs.

很多系统级的特性只能被系统软件使用，因此 应用程序开发者了解一下。
This overview and most subsequent chapters of this book focus on protected-mode
operation of the IA-32 architecture. IA-32e mode operation of the Intel 64 architecture,
as it differs from protected mode operation, is also described.
All Intel 64 and IA-32 processors enter real-address mode following a power-up or
reset (see Chapter 9, “Processor Management and Initialization”). Software then
initiates the switch from real-address mode to protected mode. If IA-32e mode operation
is desired, software also initiates a switch from protected mode to IA-32e
mode.

大部分内容我们都集中在Ia-32保护模式上，同时讲一些 IA-32e mode 不同的东西

这两种架构进入实方式都要经过启动和重启 看第九章 软件然后打开从实方式到保护方式

的开关，如果用到IA-32e mode ，那么软件就打开从保护模式到IA-32e mode 的开关