BIOS 开机自检顺序是什么？
发布网友
发布时间：2023-10-03 00:45
共2个回答
热心网友
时间：2024-11-18 21:36
When the power supply after stability, then remove RESET signal chipset, the CPU immediately FFFFOH from executed instructions. Note: this address system BIOS address range, whether BIOS or AMI BIOS, put in here's just a jump instruction, jumped to the real system BIOS in start-up code. System BIOS start-up code: the first thing to do is to POST (plus electric self-check).
POST is the main task of the detection system of some key equipment and whether there can work normally, such as memory and video CARDS, etc. If the time of the system of the speaker is not a clear and crisp "di" sound, that could be memory or display card, etc is out of order)
Computer, electric, the Power supply of main proce immediate "Power Good" low potential signal-through the clock proces (driver) of output signal and the effective RESET to CPU into state and forced to RESET the system into the ROM-BIOS program area. (note: the system BIOS first instruction is "jump star", that is, to jump to the hardware. In order to facilitate self-inspection program start to function of the realization of the BIOS when used to run, some RAM)
So most BIOS the first thing to do in the test system and low-end RAM. (note: if the test failure, so most BIOS will not fall into the RAM, the machine without any response, microcomputer you.)
Self-inspection program allows the necessary additional card the BIOS on the program first into their own system and initialization, but before that, the BIOS on the main board and find additional card the BIOS on the program, to the motherboard BIOS and before operating the system operation.
Such as display card itself contains start programs BIOS chip, the chip inside the program to start graphics boards, prepare to show other information, and displayed on the screen of the graphics version and copyright information. If the above process completed, computers began to show ROM-BIOS version, and copyright information and detect the CPU model, main frequency and memory capacity. In this process, the program will test and self-inspection DAM (memory), controller and ROM-BIOS chip bytes.
(note: these test, if mistakes, it is wrong, can lead to fatal crash or dead circulation if normal.)
To continue to check interrupt controller-timer-and expand O interface, keyboard, and the IDE interface, floppy disk, equipment and initialization.
Note: in the test if mistakes, as general error, display an error message; If the normal, continues for the next step. Before that, the machine has been judge whether the user is pressed the "Del" button, if pressed into the ROM-BIOS setup of the system, the configuration of the system (such as soft, hard disk type) in the form of parameters in CMOS RAM, and then restart.
Later, self-inspection program will according to the contents of the CMOS RAM to identify some of the system hardware configuration, and these parts initialized, if meet the CMOS RAM set parameters and system of the actual hardware will lead to wrong or not crash. If above the work is done it, computer began to read data from the hard drive, and guide the operating system, show desktop. Agree with 0 | comments
热心网友
时间：2024-11-18 21:36
当电源供电稳定后，芯片组便撤去RESET信号，CPU马上就从FFFFOH处开始执行指令。注：这个地址在系统BIOS的地址范围内，无论是BIOS还是AMI BIOS，放在这里的只是一条跳转指令，跳到系统BIOS中真正的启动代码处。系统BIOS的启动代码首先要做的事情就是进行POST(加电自检)。
POST的主要任务是检测系统中的一些关键设备是否存在和能否正常工作，如内存和显卡等。如果这个时候系统的喇叭发出的不是一声清脆的“嘀”声，那就有可能是内存条或是显示卡等出故障了）
计算机加电后，主机电源立即产生“Power Good”低电位信号→通过时钟产生(驱动)器输出有效的RESET信号→使CPU进入复位状态→并强制系统进入ROM-BIOS程序区。（注：系统BIOS区的第一条指令是“jump star”，即跳转到硬件自检程序start。为了方便地实现的功能，BIOS运行时要用到一些RAM)
因此大多数BIOS要做的第一件事就是→检测系统中的低端RAM.（注：如果检测失败，那么大多数BIOS将无法调入RAM中，开机后无任何反应，微机黑屏。）
自检程序允许必要的附加卡上的BIOS程序首先进入它们自己的系统并初始化，但在此之前，主板上的BIOS→ 找到附加卡上的BIOS程序，才能在主板BIOS和操作系统之前运行。
如显示卡本身就带有启动程序的BIOS芯片，该芯片内的程序负责启动显示卡，为显示其它信息作准备，并在屏幕上显示显示卡的版本及版权信息。如果上面的过程完成了，电脑开始显示ROM-BIOS的版本、版权信息以及检测出的CPU型号、主频和内存容量。在这个过程中，自检程序还要测试→DAM（内存）→控制器及ROM-BIOS芯片的字节数。
（注：这些检测，如果出现错误，则为致命性错误，会导致死机或死循环如果正常。）
继续检验中断控制器→、定时器→、键盘→、扩展O接口→、IDE接口→、软驱等设备并进行初始化。
注：检测中如果出现错误，作为一般性错误，显示错误信息；如果正常，则继续进行下一步。在这之前，机器一直判断用户是否按了“Del”键，如果按了就进入ROM-BIOS中的系统设置程序，将系统的配置情况(如软、硬盘型号)以参数的形式存入CMOS RAM中，然后重新启动。
之后，自检程序将根据CMOS RAM中的内容来识别系统的一些硬件设置，并对这些部件进行初始化，如果遇到CMOS RAM中的设置参数与系统实际的硬件不符就会导致错误或死机。如果以上的工作都完成了的话，电脑就开始从硬盘读取数据，引导操作系统，显示桌面。
