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  1. Joined : Jun 2015
    Posts : 213
    Windows 10
       08 Sep 2015 #1

    Alphanumeric object in the DVD BCD


    Hi

    After putting the DVD of Windows 10 in a DVD player and executing the command

    Code:
    C:\WINDOWS\system32>bcdedit /store "D:\boot\bcd"
    Windows Boot Manager
    --------------------
    identifier          {bootmgr}
    description             Windows Boot Manager
    locale                  en-US
    inherit                 {globalsettings}
    default                 {default}
    displayorder            {default}
    toolsdisplayorder       {memdiag}
    timeout                 30
    Windows Boot Loader
    -------------------
    identifier          {default}
    device                  ramdisk=[boot]\sources\boot.wim,{7619dcc8-fafe-11d9-b411-000476eba25f}
    path                    \windows\system32\boot\winload.exe
    description             Windows Setup
    locale                  en-US
    inherit                 {bootloadersettings}
    osdevice                ramdisk=[boot]\sources\boot.wim,{7619dcc8-fafe-11d9-b411-000476eba25f}
    systemroot              \windows
    bootmenupolicy          Standard
    detecthal               Yes
    winpe                   Yes
    ems                     No
    I noticed that the values of the osdevice and device elements end with an alphanumeric object.

    What is this object? There is an alias for this object?

    Thanks

    Bye
      My System SpecsSystem Spec


  2. Joined : Jul 2014
    San Jose, California
    Posts : 1,956
    Ubuntu14.04x64 MintMate17x64 Win10Prox64
       08 Sep 2015 #2
      My System SpecsSystem Spec


  3. Joined : Jun 2015
    Posts : 213
    Windows 10
       08 Sep 2015 #3

    If I run this command on another computer, this GUID changes?

    Thanks

    Bye
      My System SpecsSystem Spec


  4. Joined : Jul 2015
    Posts : 6,880
    Windows 10 Pro
       08 Sep 2015 #4

    balubeto said: View Post
    If I run this command on another computer, this GUID changes?

    Thanks

    Bye
    Yes. The GUID is pointing to the DVD drive. Think of the GUID as a serial number for that drive. Different drive in a different computer means different GUID. It's used so the program always looks in the same place for data once it starts, regardless of what drive letter is assigned, in this case back to the device that was used to boot with.

    The command bcdedit is processing the information it is reading from the BCD store, not just displaying the read only file. If you open the bcd store file in notepad, all you will see is unreadable binary garbage.
      My System SpecsSystem Spec


  5. Joined : Jun 2015
    Posts : 213
    Windows 10
       08 Sep 2015 #5

    So, can you explain one thing:

    I copied the contents of the DVD on my hard disk and then I wrote the following commands:

    Code:
    C:\WINDOWS\system32>bcdedit /store "C:\Users\Balubeto\Downloads\DVD\boot\bcd"
    Windows Boot Manager
    --------------------
    identifier              {bootmgr}
    description             Windows Boot Manager
    locale                  en-US
    inherit                 {globalsettings}
    default                 {default}
    displayorder            {default}
    toolsdisplayorder       {memdiag}
    timeout                 30
    Windows Boot Loader
    -------------------
    identifier              {default}
    device                  ramdisk=[boot]\sources\boot.wim,{7619dcc8-fafe-11d9-b411-000476eba25f}
    path                    \windows\system32\boot\winload.exe
    description             Windows Setup
    locale                  en-US
    inherit                 {bootloadersettings}
    osdevice                ramdisk=[boot]\sources\boot.wim,{7619dcc8-fafe-11d9-b411-000476eba25f}
    systemroot              \windows
    bootmenupolicy          Standard
    detecthal               Yes
    winpe                   Yes
    ems                     No
    C:\WINDOWS\system32>bcdedit /store "C:\Users\Balubeto\Downloads\DVD\boot\bcd" /set {default} osdevice ramdisk=[boot]\sources\boot.wim,{ramdiskoptions}
    Operazione completata.
    C:\WINDOWS\system32>bcdedit /store "C:\Users\Balubeto\Downloads\DVD\boot\bcd" /set {default} device ramdisk=[boot]\sources\boot.wim,{ramdiskoptions}
    Operazione completata.
    C:\WINDOWS\system32>bcdedit /store "C:\Users\Balubeto\Downloads\DVD\boot\bcd"
    Windows Boot Manager
    --------------------
    identifier              {bootmgr}
    description             Windows Boot Manager
    locale                  en-US
    inherit                 {globalsettings}
    default                 {default}
    displayorder            {default}
    toolsdisplayorder       {memdiag}
    timeout                 30
    Windows Boot Loader
    -------------------
    identifier              {default}
    device                  ramdisk=[boot]\sources\boot.wim,{ramdiskoptions}
    path                    \windows\system32\boot\winload.exe
    description             Windows Setup
    locale                  en-US
    inherit                 {bootloadersettings}
    osdevice                ramdisk=[boot]\sources\boot.wim,{ramdiskoptions}
    systemroot              \windows
    bootmenupolicy          Standard
    detecthal               Yes
    winpe                   Yes
    ems                     No
    C:\WINDOWS\system32>
    Why, in the final output, the ramdiskoptions alias is not converted into its alphanumeric code as it is done in the initial output?

    Thanks

    Bye
    Last edited by balubeto; 08 Sep 2015 at 12:30.
      My System SpecsSystem Spec


  6. Joined : Jul 2015
    Posts : 6,880
    Windows 10 Pro
       08 Sep 2015 #6

    That one I don't know. I am not that well versed in BCD functioning. Looking forward to answers that the experts might offer, though, because it is something I want to learn more about.
      My System SpecsSystem Spec


  7. Joined : Oct 2013
    Penns Forrest
    Posts : 3,506
    Win_8.1-Pro, Win_10.1607-Pro, Mint_17.3
       08 Sep 2015 #7

    balubeto said: View Post
    I copied the contents of the DVD on my hard disk and then I wrote the following commands:
    .....
    Why, in the final output, the ramdiskoptions alias is not converted into its alphanumeric code as it is done in the initial output?
    First, you should show all entries in the Boot Code (/v is verbose mode - it shows the GUID for well known objects)

    bcdedit /v /enum all

    That will help you understand the relationships.

    Code:
    Windows Boot Manager
    --------------------
    identifier              {9dea862c-5cdd-4e70-acc1-f32b344d4795}
    description             Windows Boot Manager
    locale                  en-US
    inherit                 {7ea2e1ac-2e61-4728-aaa3-896d9d0a9f0e}
    default                 {7619dcc9-fafe-11d9-b411-000476eba25f}
    displayorder            {7619dcc9-fafe-11d9-b411-000476eba25f}
    toolsdisplayorder       {b2721d73-1db4-4c62-bf78-c548a880142d}
    timeout                 30
    
    Windows Boot Loader
    -------------------
    identifier              {7619dcc9-fafe-11d9-b411-000476eba25f}
    device                  ramdisk=[boot]\sources\boot.wim,{7619dcc8-fafe-11d9-b411-000476eba25f}
    path                    \windows\system32\boot\winload.exe
    description             Windows Setup
    locale                  en-US
    inherit                 {6efb52bf-1766-41db-a6b3-0ee5eff72bd7}
    osdevice                ramdisk=[boot]\sources\boot.wim,{7619dcc8-fafe-11d9-b411-000476eba25f}
    
    . . .
    Device options -------------- identifier {7619dcc8-fafe-11d9-b411-000476eba25f} ramdisksdidevice boot ramdisksdipath \boot\boot.sdi
    If you follow the GUID reference to the identifier, it becomes clear that the Boot code on the DVD says:
    Create a RAMdisk to use as the boot device

    Boot to ramdisksdidevice {7619dcc8-fafe-11d9-b411-000476eba25f}
    Load System Deployment Image (boot\boot.sdi)
    Load WinPE (\sources\boot.wim)


    Sometimes the GUIDs are very close - so you have to read them carefully

    Windows Boot Loader
    -------------------------
    identifier {7619dcc9-fafe-11d9-b411-000476eba25f}
    device {7619dcc8-fafe-11d9-b411-000476eba25f}

    If you're going to experiment - make sure you back up your BCD, even if you're working on a different store. It's not hard to forget to specify /store and then you're working on the live BCD file.

    bcdedit /export <filename>

    Example: bcdedit /export "C:\Data\BCD Backup"

    This command exports the contents of the system store into a file. This file can be used later to restore the state of the system store. This command is only valid for the system store.

    <filename>
    The filename to be used as the destination for the export. If the filename contains spaces, it must be enclosed in quotation marks ("").
      My System SpecsSystem Spec


  8. Joined : Jun 2015
    Posts : 213
    Windows 10
       09 Sep 2015 #8

    Slartybart said: View Post
    First, you should show all entries in the Boot Code (/v is verbose mode - it shows the GUID for well known objects)

    bcdedit /v /enum all

    That will help you understand the relationships.

    Code:
    Windows Boot Manager
    --------------------
    identifier              {9dea862c-5cdd-4e70-acc1-f32b344d4795}
    description             Windows Boot Manager
    locale                  en-US
    inherit                 {7ea2e1ac-2e61-4728-aaa3-896d9d0a9f0e}
    default                 {7619dcc9-fafe-11d9-b411-000476eba25f}
    displayorder            {7619dcc9-fafe-11d9-b411-000476eba25f}
    toolsdisplayorder       {b2721d73-1db4-4c62-bf78-c548a880142d}
    timeout                 30
    
    Windows Boot Loader
    -------------------
    identifier              {7619dcc9-fafe-11d9-b411-000476eba25f}
    device                  ramdisk=[boot]\sources\boot.wim,{7619dcc8-fafe-11d9-b411-000476eba25f}
    path                    \windows\system32\boot\winload.exe
    description             Windows Setup
    locale                  en-US
    inherit                 {6efb52bf-1766-41db-a6b3-0ee5eff72bd7}
    osdevice                ramdisk=[boot]\sources\boot.wim,{7619dcc8-fafe-11d9-b411-000476eba25f}
    
    . . .
    Device options -------------- identifier {7619dcc8-fafe-11d9-b411-000476eba25f} ramdisksdidevice boot ramdisksdipath \boot\boot.sdi
    If you follow the GUID reference to the identifier, it becomes clear that the Boot code on the DVD says:
    Create a RAMdisk to use as the boot device

    Boot to ramdisksdidevice {7619dcc8-fafe-11d9-b411-000476eba25f}
    Load System Deployment Image (boot\boot.sdi)
    Load WinPE (\sources\boot.wim)
    Sometimes the GUIDs are very close - so you have to read them carefully

    Windows Boot Loader
    -------------------------
    identifier {7619dcc9-fafe-11d9-b411-000476eba25f}
    device {7619dcc8-fafe-11d9-b411-000476eba25f}

    If you're going to experiment - make sure you back up your BCD, even if you're working on a different store. It's not hard to forget to specify /store and then you're working on the live BCD file.
    bcdedit /export <filename>

    Example: bcdedit /export "C:\Data\BCD Backup"

    This command exports the contents of the system store into a file. This file can be used later to restore the state of the system store. This command is only valid for the system store.

    <filename>
    The filename to be used as the destination for the export. If the filename contains spaces, it must be enclosed in quotation marks ("").
    Code:
    C:\WINDOWS\system32>bcdedit /store "C:\Users\Balubeto\Downloads\DVD\boot\bcd" /v /enum all
    Windows Boot Manager
    --------------------
    identifier              {9dea862c-5cdd-4e70-acc1-f32b344d4795}
    description             Windows Boot Manager
    locale                  en-US
    inherit                 {7ea2e1ac-2e61-4728-aaa3-896d9d0a9f0e}
    default                 {7619dcc9-fafe-11d9-b411-000476eba25f}
    displayorder            {7619dcc9-fafe-11d9-b411-000476eba25f}
    toolsdisplayorder       {b2721d73-1db4-4c62-bf78-c548a880142d}
    timeout                 30
    Windows Boot Loader
    -------------------
    identifier              {7619dcc9-fafe-11d9-b411-000476eba25f}
    device                  ramdisk=[boot]\sources\boot.wim,{7619dcc8-fafe-11d9-b411-000476eba25f}
    path                    \windows\system32\boot\winload.exe
    description             Windows Setup
    locale                  en-US
    inherit                 {6efb52bf-1766-41db-a6b3-0ee5eff72bd7}
    osdevice                ramdisk=[boot]\sources\boot.wim,{7619dcc8-fafe-11d9-b411-000476eba25f}
    systemroot              \windows
    bootmenupolicy          Standard
    detecthal               Yes
    winpe                   Yes
    ems                     No
    Windows Memory Tester
    ---------------------
    identifier              {b2721d73-1db4-4c62-bf78-c548a880142d}
    device                  boot
    path                    \boot\memtest.exe
    description             Windows Memory Diagnostic
    locale                  en-US
    inherit                 {7ea2e1ac-2e61-4728-aaa3-896d9d0a9f0e}
    Settings Emergency Management Services
    ------------
    identifier              {0ce4991b-e6b3-4b16-b23c-5e0d9250e5d9}
    bootems                 No
    debugger settings
    -----------------
    identifier              {4636856e-540f-4170-a130-a84776f4c654}
    debugtype               Serial
    debugport               1
    baudrate                115200
    Global settings
    ---------------
    identifier              {7ea2e1ac-2e61-4728-aaa3-896d9d0a9f0e}
    inherit                 {4636856e-540f-4170-a130-a84776f4c654}
                            {0ce4991b-e6b3-4b16-b23c-5e0d9250e5d9}
    Boot Loader Settings
    -------------------
    identifier              {6efb52bf-1766-41db-a6b3-0ee5eff72bd7}
    inherit                 {7ea2e1ac-2e61-4728-aaa3-896d9d0a9f0e}
                            {7ff607e0-4395-11db-b0de-0800200c9a66}
    Hypervisor Settings
    -------------------
    identifier              {7ff607e0-4395-11db-b0de-0800200c9a66}
    description             Hypervisor Settings
    hypervisordebugtype     Serial
    hypervisordebugport     1
    hypervisorbaudrate      115200
    Device options
    --------------
    identifier              {7619dcc8-fafe-11d9-b411-000476eba25f}
    ramdisksdidevice        boot
    ramdisksdipath          \boot\boot.sdi
    C:\WINDOWS\system32>bcdedit /store "C:\Users\Balubeto\Downloads\DVD\boot\bcd" /enum all
    Windows Boot Manager
    --------------------
    identifier              {bootmgr}
    description             Windows Boot Manager
    locale                  en-US
    inherit                 {globalsettings}
    default                 {default}
    displayorder            {default}
    toolsdisplayorder       {memdiag}
    timeout                 30
    Windows Boot Loader
    -------------------
    identifier              {default}
    device                  ramdisk=[boot]\sources\boot.wim,{7619dcc8-fafe-11d9-b411-000476eba25f}
    path                    \windows\system32\boot\winload.exe
    description             Windows Setup
    locale                  en-US
    inherit                 {bootloadersettings}
    osdevice                ramdisk=[boot]\sources\boot.wim,{7619dcc8-fafe-11d9-b411-000476eba25f}
    systemroot              \windows
    bootmenupolicy          Standard
    detecthal               Yes
    winpe                   Yes
    ems                     No
    Windows Memory Tester
    ---------------------
    identifier              {memdiag}
    device                  boot
    path                    \boot\memtest.exe
    description             Windows Memory Diagnostic
    locale                  en-US
    inherit                 {globalsettings}
    Settings Emergency Management Services
    ------------
    identifier              {emssettings}
    bootems                 No
    debugger settings
    -----------------
    identifier              {dbgsettings}
    debugtype               Serial
    debugport               1
    baudrate                115200
    Global settings
    ---------------
    identifier              {globalsettings}
    inherit                 {dbgsettings}
                            {emssettings}
    Boot Loader Settings
    -------------------
    identifier              {bootloadersettings}
    inherit                 {globalsettings}
                            {hypervisorsettings}
    Hypervisor Settings
    -------------------
    identifier              {hypervisorsettings}
    description             Hypervisor Settings
    hypervisordebugtype     Serial
    hypervisordebugport     1
    hypervisorbaudrate      115200
    Device options
    --------------
    identifier              {7619dcc8-fafe-11d9-b411-000476eba25f}
    ramdisksdidevice        boot
    ramdisksdipath          \boot\boot.sdi
    C:\WINDOWS\system32>
    By chance, this is an internal alias for the "Device options" object?

    Its alphanumeric string is fixed or changes each boot or any device used? If it changes, what should I put in the osdevice and device elements to avoid boot problems?

    Thanks

    Bye
      My System SpecsSystem Spec


  9. Joined : Oct 2013
    Penns Forrest
    Posts : 3,506
    Win_8.1-Pro, Win_10.1607-Pro, Mint_17.3
       09 Sep 2015 #9

    From your code box (I removed ramdisk=[boot]\sources\boot.wim, from the Boot loader section to make the relationship clearer)

    Windows Boot Loader
    device {7619dcc8-fafe-11d9-b411-000476eba25f}
    osdevice {7619dcc8-fafe-11d9-b411-000476eba25f}
    Device options
    identifier
    {7619dcc8-fafe-11d9-b411-000476eba25f}

    You're right on target - the GUID in Bootloader referenced the information in Device options

    Does it change? Yes and no - it all depends on the ISO or tool used to create the bootable device.

    Rather than mucking about in the boot code for simple things, let the tool create what's needed.

    Why do you want to to do this? If you want to copy USB install media - just copy it - the boot structure is the same.

    It's only when you have multiple installs that you have to worry about what partition the install is on so you can tell the boot manager to load Windows from there.

    On external boot media, you always boot from the media.

    A Repair USB is a bit different - it has to know where the recovery partition is located.

    I'm not sure this is the best way to learn about the boot code. You have a starting point, now you should read a lot more.

    Here are two tools for editing BCD

    Visual BCD Editor

    EasyBCD - NeoSmart Technologies
    scroll down to the free version - registration required to download)
    alternative download: EasyBCD - MajorGeeks
      My System SpecsSystem Spec


  10. Joined : Jun 2015
    Posts : 213
    Windows 10
       10 Sep 2015 #10

    Then, the {7619dcc8-fafe-11d9-b411-000476eba25f} string always identifies the "Device options" object . Right?

    This also applies to Windows 7/8.x or this string is different?

    Thanks

    Bye
      My System SpecsSystem Spec


 
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