Opening the power start machine is almost a matter of computer enthusiasts every day, facing a boot screen appearing on the screen, we will not feel unfamiliar, but what is the computer done when the computer is displayed? what about work? I believe that some friends are not very clear, this article will introduce what is done when the computer has done from the open power to the blue sky, the computer.
Let us first understand some basic concepts. The first is a very familiar BIOS (Basic Input Output System), BIOS is the underlying code that is dealt with hardware, which provides the operating system to control the basic functions of the hardware device. BIOS includes BIOS with system BIOS (i.e. often said motherboard BIOS), graphics card BIOS and other devices (such as IDE controller, SCSI card or network card, etc.), wherein the system BIOS is the protagonist to be discussed herein because the computer's startup process is It is carried out under its control. BIOS is generally stored in the ROM (read-only memory chip), and these code will not disappear even after turning off or powered down.
The second basic concept is the address of the memory, and 32MB, 64MB, or 128MB memory is generally installed in our machine, each byte of these memory is given an address so that the CPU has access to memory. The 32MB address range is indicated by hexadecimal number is 0 ~ 1ffffh, where 0 ~ FFFFH low end 1MB memory is very special, because the initial 8086 processor can access the maximum memory only 1MB, this 1MB low end 640KB is called For basic memory, and A00H ~ bffffh is preserved to use the display card, C0000h ~ fffh is preserved to BIOS, where the system BIOS generally occupies the last 64KB or more space, the graphics card BIOS is generally at C0000h ~ C7FFFH The BIOS of the IDE controller is at C8000H ~ CBFFFH.
Ok, let's take a closer look at the launch process of your computer.
Step 1: When we press the power switch, the power is powered to the motherboard and other devices. At this time, the voltage is not stable, and the control chipset on the motherboard will send an RESET (reset) signal to the CPU. Let the CPU automatically return to the initial state, but the CPU will not immediately perform the instructions immediately. When the chipset detected that the power supply has started to stabilize power (of course, from the unstable to a stable process is just a moment), it removes the RESET signal (if it is manually pressing the RESET button on the computer panel to restart the machine, then loose When the button is opened, the chipset will remove the RESET signal), and the CPU immediately starts executing instructions from the address FFF0H. From the previous introduction, this address is actually within the address range of the system BIOS, whether it is Award BIOS or Ami BIOS, Placing is just a jump instruction, jumps to the real start code in the system BIOS.
Step 2: The system BIOS startup code is the first thing to do is to perform Post (Power-On Self Test, self-test after power-on), and the main task of POST is to detect some key devices in the system and whether it can work properly. For example, devices such as memory and graphics cards. Since POST is the earliest test process, the graphics card has not been initialized. If the system BIOS found some fatal errors during POST, for example, there is no memory or memory problem (at this point only 640K regular memory), Then the system BIOS will directly control the speaker to report the error, and the length of the sound represents the type of error. Under normal circumstances, the POST process is very fast. We have almost unable to feel its presence, and other code will be called for more complete hardware detection after POST. Step 3: Next, the system BIOS will find the graphics card's BIOS, before, the start address of the ROM chip stores the graphics card BIOS is usually set at C0000h, and the system BIOS will call its initialization code after finding the graphics BIOS in this place. The graphics card is initialized by the graphics card BIOS. At this time, most graphics cards will show some initialization information on the screen, introduce manufacturers, graphic chip types, etc., but this picture is almost a flash. The system BIOS will then find the BIOS program of other devices. After finding, the initialization code to be called inside these BIOS is to initialize the relevant device.
Step 4: After finding the BIOS of all other devices, the system BIOS will display its own boot screen, including the type, serial number and version number of the system BIOS.
Step 5: The system BIOS will then detect and display the type and operating frequency of the CPU, then start testing all the RAM, and simultaneously display the progress of the memory test on the screen, we can decide to use the simple consumption in the CMOS settings or Detailed time consumption.
Step 6: After the memory test passes, the system BIOS will start some standard hardware devices installed in the system, including hard drives, CD-ROMs, serial ports, parallel ports, floppy drives, etc., and most newer version of the system BIOS is here. The timing parameters, hard disk parameters, and access modes, etc. of the memory are also automatically detected and set in the process.
Step 7: After the standard equipment is detected, the system BIOS inside the system BIOS will begin to detect and configure the plug-and-play device installed in the system. After finding a device, the system BIOS will display it on the screen. The name and model of the device, and the device allocates the interrupt, DMA channel, and I / O ports.
Step 8: All hardware has been detected, and the multi-system BIOS will re-clear the screen and display a table on the screen, which roughly lists the various standard hardware devices installed in the system. And the resources they use and some related work parameters.
Step 9: Next, the system BIOS will update the ESCD (Extended System Configuration Data). ESCD is a means of system BIOS to exchange hardware configuration information with operating systems, which are stored in CMOS (a small special RAM, powered by batteries on the motherboard). Usually the ESCD data will only be updated only after the system hardware configuration changes, so we can see information such as "Update Escd ... Success" when the machine is started, but the system BIOS of some motherboard is saved when ESCD data. Using the Data format with Windows 9x, Windows 9X modifies the ESCD data into its own format during its own startup process, but when the machine is started, even if the hardware configuration does not change, the system BIOS will also The ESCD's data format is changed, and this loop will cause the system BIOS to update the ESCD when the machine is started, which is why some machines will display relevant information at each time startup. Step 10: After the ESCD is updated, the system BIOS startup code will perform its last job, that is, start from the floppy disk, hard disk or optical drive from the floppy disk, hard disk, or optical drive according to the user-specified startup order. Taken from the C drive as an example, the system BIOS will read and perform the main boot record on the hard disk. The main boot record will then find the first active partition from the partition table, then read and execute the partition boot record of this activity partition, The partition boot record will be responsible for reading and executing IO.SYS, which is the most basic system files of DOS and Windows 9x. Windows 9x's IO.SYS first initializes some important system data, then show our familiar blue sky and white clouds, under this screen, Windows will continue to perform boot and initialization of the DOS section and the GUI (graphical user interface) section. jobs.
If the system is installed in the system, the main boot record will typically replace the boot code of the software, which will allow the user to select an operating system, then read and execute the basic operating system. Boot code (the basic boot code of DOS and Windows is partition boot record). The above introduction is the computer to complete the various initialization works to be completed when the power switch (or pressing the reset button) is turned on. If we press the Ctrl Alt DEL key button under DOS (or select Restart Computer from Windows) to heat Start, the POST process will be jumped, starting directly from the third step, and the detection CPU and memory testing of the fifth step will not be done again. We can see that whether it is cold start or hot start, the system BIOS has repeatedly repeated these things again and again, but it is not paying attention to things. However, it is these monotonic hardware testing steps to provide us with a computer. basis.
Now the mainstream brand machine randomly installed in the market is generally Windows XP, but some users may still have a unique closure of Windows 98, Windows ME or Windows 2000, etc., I hope to do not destroy the original operating system Next, install the above operating system. According to regularly, if we do not use third-party software, we should install it in order from low versions to high versions when installing Microsoft's Windows Series operating system; if you use third-party software, it will involve The copyright and usage problem of the software used is obviously not appropriate for general users. In fact, according to our method provided herein, any software that does not use third parties can also achieve the operating system to reach, and it is very simple! For example, my Lenovo brand, the hard disk C-zone installs Windows XP home version, the C area file format is FAT 32, and the file system of other partitions is also FAT 32. The file system that uses this article to install Windows 98, C-zone, and installation of Windows 98 needs to be converted to FAT 32, otherwise a third party startup software is required. Of course, if the file format is NTFS, we can use "Partition Magic" software to do not change it to FAT 32.
Prepare: Support for CD-ROM-drive booting Windows 98 / Me boot floppy disk; debug.exe file (copy from the Windows / Command folder to the startup floppy disk, or reclaim it from ebd.cab).
step:
first part:
Install Windows 98 / ME operating system
1. Put the Windows 98 / ME installation CD into the drive; 2. Use the production of a good start disk to start the computer;
3. Install the operating system according to the normal installation of Windows 98 / ME; just do not install Windows 98 / ME in the partition where Windows XP is located;
4. After installation, start the computer to the Windows 98 / ME operating system.
the second part:
Modify "Bootsect.dos" file
After installing the Windows 98 / ME operating system, you will modify the startup files necessary to Windows XP, we need to modify the "Bootsect.DOS" file to fix its boot file.
1. Open "Notepad" or other text editing software to make "read.scr" (file name can be changed), the content is as follows:
L 100 2 0 1
N c: /bootsect.dos
R bx
0
R CX
200
W
Qi
2. Copy the above-made files to the boot disk;
3. Start your computer to DOS mode with the boot disk;
4. Modify the file properties of "Bootsect.DOS", use the following command:
Attrib C: /Bootsect.dos -s -h -r
5. Enter: Debug at the command prompt: Debug
the third part:
Fix Windows XP
1. Modify the boot option in the BIOS, enabling the computer from the CD-ROM drive; you can also use the startup disk just produced to start the computer, then enter f: /i386/winnnt.exe under the command prompt (f is the drive letter of the CD drive ) To run installation instructions;
2. When you install Windows XP, we have to select the "Repair" item to fix the installed operating system in your hard drive;
3. Select the operating system you need to log in, usually "1", type "1", and enter the administrator password (set when installing, the user who installs the Windows XP Home Edition Lenovo brand only needs to press Enter " That is, 4. Type "FixBoot" at the command prompt to fix the startup file of Windows XP;
5. Take out the Windows XP installation CD in the CD-ROM drive, restart your computer, and set it to the hard drive from the hard drive in the BIOS.
Now, you can see the startup menu of Windows XP and you can select the operating system you want. After restarting your computer, we can choose the operating system that you need to start. Is not it simple?
fourth part:
Win2000 under WinXP
After installation of Windows XP, the Windows 2000 is installed more simpler than the installation 98 or ME. The methods mentioned herein do not need third-party software, and can be operated on FAT32 or NTFS file format.
1. First, open the Control Panel, select "Folder Item" and double-click, select "View" in the Folder option window, and hide protected operating system files in "Advanced Settings" "√" removed to show the two system files we need: "NTLDR" and "NTDetect.com";
2. Copy the above two files into a floppy disk;
3. Modify the boot options in the BIOS to start the computer from the CD and run the installation of Windows 2000;
4. Install Windows 2000 by normal method;
5. After the installation is complete, start the computer to Windows 2000;
6. Copy us to the two files in the floppy to the root directory of the C area; if the system prompts can't copy, the user needs to modify the properties of the above two files, remove their "read-only" and "hidden" attributes.
Description: We do this here because WIN XP version "NTLDR" and "NTDetect.com" support start Windows 2000, but the latter does not support boot to the former, so we need to do more.
