This article is about startup process in Windows Vista and later versions. For older versions, see NTLDR.
The Windows Boot Manager (BOOTMGR) is the bootloader provided by Microsoft for Windows NT versions starting with Windows Vista and its server counterpart. It is the first program launched by the BIOS or UEFI of the computer and is responsible for loading the rest of Windows.[1] It replaced the NTLDR present in older versions of Windows.
On system with BIOS firmware, the BIOS invokes MBR boot code from a hard disk drive at startup. The MBR boot code and the VBR boot code are OS-specific. In Microsoft Windows, the MBR boot code tries to find an active partition (the MBR is only 512 bytes), then executes the VBR boot code of an active partition. The VBR boot code tries to find and execute the bootmgr file from an active partition.[3]
On systems with UEFI firmware, UEFI invokes bootmgfw.efi from an EFI system partition at startup, starting the Windows Boot Manager.
Operationedit
Once launched the Windows Boot Manager reads the Boot Configuration Data to determine what operating systems are present and if it should present the user with a menu allowing them to select which operating system to boot. Before Windows Vista, this data was contained in boot.ini.
These menu entries can include:
Options to boot Windows Vista and later by invoking winload.exe.
Options to resume Windows Vista and later from hibernation by invoking winresume.exe.
Options to boot a prior version of the Windows NT family by invoking its NTLDR.
The operating system is loaded by individual boot loaders for each install of Windows, called the Windows Boot Loader.
winload.exeedit
The Windows Boot Manager invokes winload.exe—the operating system boot loader—to load the operating system kernel executive (ntoskrnl.exe) and core device drivers. In that respect, winload.exe is functionally equivalent to the operating system loader function of NTLDR in prior versions of Windows NT. In UEFI systems, the file is called winload.efi and the file is always located at \windows\system32 or \windows\system32\boot.
winresume.exeedit
If the computer has recently hibernated, then bootmgr will instead invoke winresume.exe. In UEFI systems, the file is called winresume.efi and is always located at \windows\system32 or \windows\system32\boot.[4]
Boot Configuration Dataedit
Boot Configuration Data (BCD) is a firmware-independent database for boot-time configuration data.[5] It is used by Microsoft's Windows Boot Manager and replaces the boot.ini that was used by NTLDR.
Boot Configuration Data is stored in a data file that has the same format as Windows Registry hives and is eventually mounted at registry key HKEY_LOCAL_MACHINE\BCD00000[6] (with restricted permissions[7]). For UEFI boot, the file is located at /EFI/Microsoft/Boot/BCD on the EFI System Partition. For traditional BIOS boot, the file is at /boot/BCD on the active partition.[8]
^barrygolden. "Boot and UEFI - Windows drivers". learn.microsoft.com. Retrieved 2023-03-20.
^de Boyne Pollard, Jonathan. . Frequently Given Answers. Archived from the original on August 26, 2016.
^"Boot Sequence of Windows Multi-Boot - Multibooters.com". www.multibooters.com. Retrieved 2020-11-19.
^Hudek, Ted; Marshall, Don; Graf, Eliot (23 April 2019). "Overview of Boot Options in Windows". Microsoft Docs Hardware Dev Center. Microsoft. from the original on 21 April 2020. Retrieved 21 April 2020.
^Marshall, Don. "Overview of Boot Options in Windows - Windows drivers". learn.microsoft.com. Retrieved 2023-03-20.
^ abRussinovich, Mark (8 November 2011). "Fixing Disk Signature Collisions". Mark's Blog. Microsoft Corporation. Microsoft TechNet. Retrieved 5 February 2021.
^"Why can't I edit the system BCD store via regedit?".
^Microsoft. . Archived from the original on 16 January 2010.
^Pauly. . Archived from the original on 2013-12-28. Retrieved 2013-12-27.
de Boyne Pollard, Jonathan. "The Windows NT 6 boot process". Frequently Given Answers.
April 12, 2024
windows, boot, manager, this, article, about, startup, process, windows, vista, later, versions, older, versions, ntldr, this, article, needs, additional, citations, verification, please, help, improve, this, article, adding, citations, reliable, sources, unso. This article is about startup process in Windows Vista and later versions For older versions see NTLDR This article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources Windows Boot Manager news newspapers books scholar JSTOR May 2010 Learn how and when to remove this template message The Windows Boot Manager BOOTMGR is the bootloader provided by Microsoft for Windows NT versions starting with Windows Vista and its server counterpart It is the first program launched by the BIOS or UEFI of the computer and is responsible for loading the rest of Windows 1 It replaced the NTLDR present in older versions of Windows Windows Boot ManagerWindows Boot Manager operation system select menuOther namesBOOTMGRDeveloper s MicrosoftOperating systemWindowsPredecessorNTLDRTypeBootloaderLicenseProprietaryThe boot sector or UEFI loads the Windows Boot Manager a file named BOOTMGR on either the system or the boot partition accesses the Boot Configuration Data store and uses the information to load the operating system through winload exe or winresume exe 2 Contents 1 Launching 2 Operation 3 Operating system loading 3 1 winload exe 3 2 winresume exe 4 Boot Configuration Data 4 1 bcdedit 5 See also 6 References 7 Further readingLaunching editOn system with BIOS firmware the BIOS invokes MBR boot code from a hard disk drive at startup The MBR boot code and the VBR boot code are OS specific In Microsoft Windows the MBR boot code tries to find an active partition the MBR is only 512 bytes then executes the VBR boot code of an active partition The VBR boot code tries to find and execute the bootmgr file from an active partition 3 On systems with UEFI firmware UEFI invokes bootmgfw efi from an EFI system partition at startup starting the Windows Boot Manager Operation editOnce launched the Windows Boot Manager reads the Boot Configuration Data to determine what operating systems are present and if it should present the user with a menu allowing them to select which operating system to boot Before Windows Vista this data was contained in boot ini These menu entries can include Options to boot Windows Vista and later by invoking winload exe Options to resume Windows Vista and later from hibernation by invoking winresume exe Options to boot a prior version of the Windows NT family by invoking its NTLDR Options to load and to execute a volume boot record Operating system loading editFurther information Booting process of Windows NT The operating system is loaded by individual boot loaders for each install of Windows called the Windows Boot Loader winload exe edit The Windows Boot Manager invokes winload exe the operating system boot loader to load the operating system kernel executive ntoskrnl exe and core device drivers In that respect winload exe is functionally equivalent to the operating system loader function of NTLDR in prior versions of Windows NT In UEFI systems the file is called winload efi and the file is always located at windows system32 or windows system32 boot winresume exe edit If the computer has recently hibernated then bootmgr will instead invoke winresume exe In UEFI systems the file is called winresume efi and is always located at windows system32 or windows system32 boot 4 Boot Configuration Data editBoot Configuration Data BCD is a firmware independent database for boot time configuration data 5 It is used by Microsoft s Windows Boot Manager and replaces the boot ini that was used by NTLDR Boot Configuration Data is stored in a data file that has the same format as Windows Registry hives and is eventually mounted at registry key HKEY LOCAL MACHINE BCD00000 6 with restricted permissions 7 For UEFI boot the file is located at EFI Microsoft Boot BCD on the EFI System Partition For traditional BIOS boot the file is at boot BCD on the active partition 8 bcdedit edit bcdeditDeveloper s MicrosoftOperating systemMicrosoft WindowsTypeCommandLicenseProprietary commercial softwareWebsitedocs wbr microsoft wbr com wbr en us wbr windows server wbr administration wbr windows commands wbr bcdeditBoot Configuration Data may be altered using a command line tool bcdedit exe using the Registry Editor 6 regedit exe using Windows Management Instrumentation or with third party tools such as EasyBCD BOOTICE 9 or Visual BCD Editor 10 Boot Configuration Data allows for third party integration so anyone can implement tools like diagnostics or recovery optionsSee also editBooting process of Windows NT Windows Vista I O technologiesReferences edit barrygolden Boot and UEFI Windows drivers learn microsoft com Retrieved 2023 03 20 de Boyne Pollard Jonathan The Windows NT 6 boot process Frequently Given Answers Archived from the original on August 26 2016 Boot Sequence of Windows Multi Boot Multibooters com www multibooters com Retrieved 2020 11 19 Hudek Ted Marshall Don Graf Eliot 23 April 2019 Overview of Boot Options in Windows Microsoft Docs Hardware Dev Center Microsoft Archived from the original on 21 April 2020 Retrieved 21 April 2020 Marshall Don Overview of Boot Options in Windows Windows drivers learn microsoft com Retrieved 2023 03 20 a b Russinovich Mark 8 November 2011 Fixing Disk Signature Collisions Mark s Blog Microsoft Corporation Microsoft TechNet Retrieved 5 February 2021 Why can t I edit the system BCD store via regedit Microsoft Knowledge Base Article ID 2004518 Archived from the original on 16 January 2010 Pauly BOOTICE board index Archived from the original on 2013 12 28 Retrieved 2013 12 27 Bo Yans Visual BCD Editor Further reading editde Boyne Pollard Jonathan The Windows NT 6 boot process Frequently Given Answers Retrieved from https en wikipedia org w index php title Windows Boot Manager amp oldid 1216729085 Boot Configuration Data, wikipedia, wiki, book, books, library,
