什么是BIOS
you are probably very familiar with two different types of software:the operating system and the applications
你可能对两种类型的软件很熟悉:操作系统和应用软件
Inside the above-mentioned ROM thrcedifferent programs are stored (actually burned).The Basic Input and Output System (BIOS) that is
responsible for teaching the main processor how todeal with basic devices, such as floppy unit or harddisk and so on; the Power on Self Test(POST)which is the program in charge of the self test that
is executed every time PC is powered up (likememory counting, for instance); and the Setupwhich is the program that allows the alteration ofthe parameters stored in the configuration memory（CMOS).
在上述只读存储器中存储着三种不同类型的程序（事实上是烧录上去的）。基本的输入输出系统（BIOS程序）负责
指导主处理器如何控制像软盘驱动器、硬盘之类的基本设备。加电自检程序（POST）是负责在每次计算机开机时执行
自检测的程序（比如内存容量检测）。设置程序（Setup）则是种专门用来修改CMOS中存储参数的程序
BIOS的任务是什么
The BIOS software has a number of different roles,but its most important role is to load the operating system
BOIS软件要执行许多不同的任务，但最重要的任务是载入操作系统
1. Check the CMOS Setup for custom settings
2. Load the interrupt handlers and device drivers
3.Initialize registers and power management
4.Perform the Power on Self Test(POST)
5.Display system settings
6.Determine which devices are bootable
7.Initiate the bootstrap sequence
1 检测 CMOS 常规设置
2.载入中断处理程序和设备驱动程序
3.初始化寄存器和电源管理
4.执行加电自检程序（POST）
5.显示系统设置
6.确定可启动设备
7.开始自举程序