Overview This article describes the startup process of Microsoft Windows XP on an x86-architecture computer designed to give readers a better understanding of the basics of Windows XP Professional launch. With this knowledge in mind, when a problem occurs in the startup, the solution can be found faster to avoid all possible losses. However, it should be noted that this article does not cover fault handling and any explanation of faults. This article only introduces the Windows XP boot/boot process. Table of Contents 1. Overview of the Windows XP Boot Phase 2. Details of each boot phase Overview of the Windows XP boot phase From the startup of the computer switch to the startup of the computer to the login to the desktop, the following phases have been followed: 1. Pre-boot ( Pre-Boot phase; 2. Boot phase; 3. Load kernel phase; 4. Initialize kernel phase; 5. Log in. A detailed description of each startup phase a) The pre-boot phase is when the computer power is turned on to start the computer, and before the Windows XP Professional operating system starts, we call it the Pre-Boot phase. In the phase, the computer first runs Power On Self Test (POST), which detects the total memory of the system and the status of other hardware devices. If the computer system's BIOS (basic input/output system) is plug-and-play, the computer hardware device will be verified and configured. The computer's basic input/output system (BiOS) locates the computer's boot device, and then the MBR (Master Boot Record) is loaded and running. In the pre-boot phase, the computer is going to load the NTLDR file for Windows XP. b) Boot phase The Windows XP Professional boot phase consists of four small phases. First, the computer goes through the initial Boot Loader, where NTLDR converts the computer microprocessor from real mode to 32-bit flat memory mode. In real mode, the system reserves 640kb of memory for MS-DOS, and the rest of the memory is treated as extended memory. In 32-bit flat memory mode, the system (Windows XP Professional) treats all memory as available memory. Next, NTLDR launches the built-in mini-file system drivers. Through this step, NTLDR can identify each partition formatted with NTFS or FAT file system to discover and load Windows XP Professional, here, the initial boot loader stage. It is over. Then the system comes to the operating system selection phase. If the computer has more than one operating system installed (that is, multiple systems), and the boot.ini is properly set to provide the operating system selection, the computer display will display an operating system menu. This is the result of NTLDR reading boot.ini. (As for the operating system menu, because the temporary conditions are not enough, there is no way to take a screenshot, but the author simulates one, see Figure 1.) In boot.ini, it mainly contains the following contents: [boot loader] timeout=30 default=multi(0) Disk(0)rdisk(0)partition(1)\\Windows [Operating systems] multi(0)disk(0)rdisk(0)partition(1)\\WINDOWS="Microsoft Windows XP Professional" /fastdetect multi(0)disk (0) rdisk(0)partition(2)\\WINNT="Windows Windows 2000 Professional" where multi(0) represents the disk controller, disk(0)rdisk(0) represents the disk, and partition(x) represents the partition. NTLDR is the location of the system files for Windows XP Professional from here. (*This article will not explain the composition of boot.ini in more detail, because it has little to do with this topic. If you want to know, you can go to some special websites to check the relevant information.) If there is only one operation in boot.ini System option, or set the timeout value to 0, the system does not appear in the operating system selection menu, directly to the unique system or the default system. After selecting to start Windows XP Professional, the operating system selection phase ends and the hardware detection phase begins. During the hardware detection phase, ntdetect.com will collect a list of computer hardware information and return the list to NTLDR. The purpose of this is to facilitate the later addition of this hardware information to the hardware under the registry HKEY_LOCAL_MacHINE. After the hardware detection is completed, enter the configuration selection phase. If your computer contains multiple hardware profile lists, you can select it by pressing the up and down buttons. If there is only one hardware profile, the computer does not display this screen and loads Windows XP Professional directly with the default profile. The boot phase ends. In the boot phase, the files used by the system are: NTLDR, Boot.ini, ntdetect.com, ntokrnl.exe, Ntbootdd.sys, bootsect.DOS (optional). c) Loading the kernel phase In the kernel loading phase, ntldr loads ntokrnl.exe called the Windows XP kernel. The system loaded the Windows XP kernel but did not initialize it. Then ntldr loads the hardware abstraction layer (HAL, hal.dll). Then, the system continues to load the HKEY_LOCAL_MACHINE\\system key. NTLDR reads the select key to determine which Control Set will be loaded. The control set contains the drivers for the device and the services that need to be loaded. NTLDR loads the lowest device driver with the start key value of 0 under HKEY_LOCAL_MacHINE\\system\\service\\.... When the Current Control Set, which is the mirror of the Control Set, is loaded, ntldr passes control to the kernel, and the initialization kernel phase begins. d) Initialize the kernel phase At the beginning of the initialization kernel phase, the colored Windows XP logo and progress bar are displayed in the center of the screen. At this stage, the system completes the four tasks that are started: The kernel uses the hardware detection. The data was created to create the HKEY_LOCAL_MacHINE\\HARDWARE key.内核 The kernel creates a Clone Control Set by copying the Control Set by referencing the default value of HKEY_LOCAL_MacHINE\\system\\Current. The Clone Control Set configuration is a backup of computer data, does not include changes in startup, and will not be modified. The system completes initialization and loads the device driver. The kernel initializes the underlying drivers that are loaded during the loading kernel phase. The kernel then scans the device driver with the start key value of 1 under HKEY_LOCAL_MacHINE\\system\\CurrentControlSet\\service\\. These device drivers are initialized when they are loaded. If an error occurs, the kernel uses the ErrorControl key value to determine what to do. When the value is 3, the error flag is Crisis/Key. The first time the system encounters an error, it will be restarted with LastKnownGood Control Set. Startup, if the startup using LastKnownGood Control Set still generates an error, the system reports that the startup fails, the error message will be displayed, the system stops starting; when the value is 2, the error condition is serious, the system fails to start and restarts with LastKnownGood Control Set, if the system starts Already using the LastKnownGood value, it ignores the error and continues to start; when the value is 1, the error is normal, the system will generate an error message, but will still ignore the error and continue to start; ignore the value when the value is 0, the system Continue to run without displaying any error messages. Session Manager starts the Windows XP Advanced Subsystem and services. Session Manager starts controlling all input and output devices and accesses the Win32 subsystem of the monitor screen and the Winlogon process. Initially, the initial Kernel is completed. e) Log in Winlogon.exe starts Local Security Authority, and Windows XP Professional welcome screen or login dialog box. At this time, the system may continue to initialize the driver that has not been completed in the background.提示 Prompt for a valid username or password. The Service Controller finally executes and scans HKEY_LOCAL_MacHINE\\SYSTEM\\CurrentControlSet\\Servives to check if there are still services to load. The Service Controller looks for a service with a start key value of 2 or higher. The service loads according to the value of start and the values of DependOnGroup and DepandOnService. . Windows XP startup is considered complete only after the user successfully logs in to the computer. After successful login, the system copies the Clone Control Set to the LastKnownGood Control Set. After completing this step, the system means that the system has been successfully booted. Conclusion This article briefly describes the Windows XP Professional boot/boot process on a 32-bit computer, including each startup phase, as well as detailed steps in the phase. Although this article does not mention error handling, by letting the reader know about these startup processes, they become more comfortable and easier to find the cause of the error when they encounter an error. References [1] Microsoft Windows XP Professional Help; [2] MCSE: Windows XP Professional Study Guide. Sybex Press. [3] MCSE Training Kit Microsoft Windows XP Professional. Microsoft Press.