Computer boot process 011 106 to understand how

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Computer Boot Process 0:11-1:06 To understand how Windows boot, it's helpful to divide the startup process into four stages. The first stage is the power-on self-test post, POST. The POST process verifies the system hardwareand initializes the computer. The second stage is the boot loader stage. This is the stage where the computer looks for and identifies the location of the operating system files. The boot loader is an intermediary between the POST process and the operating system that helps the computer identify where the operating system exists. On older systems, this is handled by the BIOS. On newer systems, this is handle by the UEFI. The third step is the operating system load. During this process, the operating system loads system files, critical drivers, and the registry. The fourth stage is user logon. This stage involves loading the user profile along with any additional drivers and other settings. Windows Bootloaders 1:07-1:27 In this lesson, we're going to focus on the Windows portion of the boot process, starting with the boot loader phase. The boot loader's job is to locate and load an operating system. On Windows XP and earlier, the boot loader program is called NTLDR. For Windows Vista and later, the boot loader program is called Windows Boot Manager. BOOTMGR 1:28-2:23 There are two versions of Boot Manager, or Bootmgr. Bootmgr.exe is used on Windows systems running on BIOS-based hardware. Bootmgr.efi is used on Windows systems running on UEFI-based hardware. The boot loader maintains a database that identifies available operating systems on the computer.For NTLDR, this file is the boot.ini file. When NTLDR executes, it looks at the boot.ini file to identify where the operating system files are located. For Bootmgr, this information is stored in the boot configuration database, or BCD. The BCD file is a binary database, so it cannot be edited with a text editor. Instead, you must use a command line toolsuch as BCDEdit.exe to read and modify the list of available operating systems. Operating System Load Phase 2:24-2:54 The next step in the boot process is to load the Windows operating system files. This process works differently for different versions of Windows. If you're running older versions of Windows prior to Windows Vista, NTLDR continues the process of loading the operating system. It uses a program called NT Detect to help identify the hardware in the system and load the necessary drivers. If you're running Windows Vista or later, the Windows boot loader, Winload program, takes over the loading of the operating system. WINLOAD 2:55-3:20 As with Boot Manager, there are two different versions of Winload. Winload.exe is used on Windows systems running on BIOS-based hardware. Winload.efi is used on Windows systems running on UEFI-based hardware.
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  • Spring '14
  • Task Manager, Hard disk drive

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