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Windows Vista Info on Vista's New Boot Loader

Discussion in 'Legacy Windows' started by Steve R Jones, 2006/06/16.

  1. 2006/06/16
    Steve R Jones

    Steve R Jones SuperGeek Staff Thread Starter

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    Windows Vista introduces a new boot loader architecture; a new firmware-independent boot configuration and storage system called Boot Configuration Data (BCD); and a new boot option editing tool, BCDEdit (BCDEdit.exe). These components are designed to load Windows more quickly and more securely.

    The traditional Windows NT boot loader, Ntldr, is replaced by Windows Boot Manager (Bootmgr.exe) and a set of system-specific boot loaders. In the new configuration, Windows Boot Manager is generic and unaware of the specific requirements for each operating system, and each system-specific boot loader is optimized for the system that it loads.

    Where is the boot.ini?
    On BIOS-based computers that are running only Windows Vista, the Boot.ini text file is gone (not hidden) and any remnants of it on interim beta test builds are ignored. On computers with both earlier versions of Windows and with Windows Vista, the Boot.ini file remains to support the older versions but it does not affect booting in Windows Vista.

    On EFI-based computers that are running Windows Vista, boot options are still stored in NVRAM. However, in Windows Vista you use BCDEdit to edit boot options on an EFI-based computer just as you would on a BIOS-based computer, instead of accessing NVRAM directly by using Windows APIs or specialized tools such as NvrBoot.

    Windows Vista also includes new BCD classes that are supported by the WMI provider and enable you to edit BCD programmatically. For information about BCD classes, see the end of this tip.



    Introduction


    The Bcdedit.exe command-line tool can be used to add, delete and edit entries in the BCD store which contains objects. Each object is identified by a GUID (Globally Unique Identifier). Every drive or partition on the system will have its own GUID and could be {legacy} (to describe a drive or partition on which a pre-Windows Vista operating system), {default} (to describe the drive or partition containing the current default operating system), or {current} (to describe the current drive or partition one is booted to), or for example {c34b751a-ff09-11d9-9e6e-0030482375e7} (to describe another drive or partition on which an operating system has been installed).

    Bcdedit.exe is located in the \Windows\System32 directory of the Windows Vista partition and can be accessed only from the Command Prompt which is found on the Windows Vista start menu at Start>All Programs>Accessories. Then right click on the dos prompt and hit "Run as Administrator ". Use basic dos commands like Cd.. (to go back a directory) and "cd windows" (to go foward to the windows directory from the current directory), once you have navigated to the C:/windows/system32 folder enter "bcdedit" in the command prompt.


    BCDEDIT Commands

    bcdedit /? Shows all commands one is able to use

    bcdedit.exe /? CREATESTORE Shows detailed information for the command CREATESTORE or any other command available in bcdedit as shown when running bcdedit /? followed by the particular command more information is required for.

    bcdedit or bcdedit /enum all Shows the current structure of your boot configuration data.
    The GUID tags {xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx} of all Windows installations present on your computer will be displayed.


    Create a Backup

    It is strongly recommended that one creates a backup of the BCD store before making any changes to it.

    bcdedit /export "D:\BCD Backup\Bcd Backup" Creates a backup to a pre-created folder, in this case "BCD Backup" on drive D:

    bcdedit /import "D:\BCD Backup\Bcd Backup" Restores the backup previously created


    Making Changes to the Boot Configuration Data

    bcdedit /set {legacy} Description "Windows XP Professional SP2" Changes the text description of the "Legacy" OS line in the boot menu. The quotation marks must be included in the command

    bcdedit /set {current} description "Windows Vista Build 5270 x86" Changes the text of the boot menu line for the Vista or non-Vista installation one is currently booted to, from the default "Microsoft Windows" or other description to that shown in the quotation marks

    bcdedit /set {5189b25c-5558-4bf2-bca4-289b11bd29e2} description "Windows Vista Build 5270 x64" Changes the text of the boot menu line for any other Vista installation. One must use the GUID for that particular installation as shown when one runs the bcdedit or bcdedit /enum all command

    bcdedit /default {current} Sets the current Windows installation one is booted to as the default Windows boot OS

    bcdedit /default {5189b25c-5558-4bf2-bca4-289b11bd29e2} Sets the referenced Windows OS as the {default} Windows boot OS

    bcdedit /default {legacy} Sets the legacy (Windows XP) OS as {default} boot item

    bcdedit /displayorder Sets the display order of boot menu items for example:

    bcdedit.exe /displayorder {legacy} {current}

    bcdedit /timeout 15 Changes the default 30 second time-out of the boot menu to 15 seconds or any other value inserted.


    Correcting changes to the Partition/Disk structure

    Where a partition or a hard drive has been added or removed and has caused the partition/disk structure to change, this can be corrected by running these commands in the order shown:

    X:\>X:\boot\fixntfs.exe -lh -all (Where X: is the drive/partition on which the folder "boot" is to be found)

    bcdedit /set {5189b25c-5558-4bf2-bca4-289b11bd29e2} device partition=X: Changes boot partition of the OS whose GUID is indicated. (Where X: is new drive/partition required). Must be used together with the osdevice command below

    bcdedit /set {5189b25c-5558-4bf2-bca4-289b11bd29e2} osdevice partition=X: Changes boot partition of the OS whose GUID is indicated. (Where X: is new drive/partition required). Must be used together with the device command above
     

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