Windows 7 : Customizing Startups Using the Boot Configuration Data

Choose the operating system or tool you want to start:
(Use the arrow keys to highlight your choice.)
     Earlier version of Windows
     Windows 7

To specify an advanced option for this choice, press F8.
Seconds until highlighted choice will be started automatically: 30

Tools:
     Windows Memory Diagnostic

If you do nothing at this point, Windows 7 will boot automatically after 30 seconds. Otherwise, you select the operating system you want and then press the Enter key to boot it. (To switch between the operating system menu and the Tools menu, press the Tab key.) The specifics of this menu are determined by the Boot Configuration Data (BCD), a new data store that replaces the BOOT.INI file used in earlier versions of Windows. BOOT.INI still exists, but it’s used only for loading the legacy operating systems in multiboot setups. Why the change? There are three main reasons:

• It didn’t make sense to have two different types of boot information stores: one for BIOS-based systems and another for EFI-based systems. BCD creates a common store for both types of operating systems.

• The need to support boot applications, which refers to any process that runs in the boot environment that the Windows Boot Manager creates. The main types of boot applications are Windows 7 partitions, legacy installations of Windows, and startup tools, such as the Windows Memory Diagnostic that appears in the Windows Boot Manager menu. In this sense, Windows Boot Manager is a kind of miniature operating system that displays an interface (the Windows Boot Manager menu) that lets you select which application you want to run.

• The need to make boot options scriptable. The BCD exposes a scripting interface via a Windows Management Instrumentation (WMI) provider. This enables you to create scripts that modify all aspects of the BCD.

Windows 7 gives you four methods to modify some or all the data in the BCD store:

• The Startup and Recovery feature

• The System Configuration utility

• The BCDEDIT command-line utility

• The BCD WMI provider

Using Startup and Recovery to Modify the BCD

You can modify a limited set of BCD options using the Startup and Recovery dialog box: the default operating system, the maximum time the Windows Boot Manager menu is displayed, and the maximum time the Windows 7 startup recovery options are displayed. Here are the steps to follow:

Using the System Configuration Utility to Modify the BCD

For more detailed control over the BCD store, you can modify the data by using the System Configuration Utility. To start this program, follow these steps:

1.	Select Start, type msconfig, and then press Enter. The System Configuration Utility window appears.
2.	Select the Boot tab, shown in Figure 2. Figure 2. In the System Configuration Utility, use the Boot tab to modify the BCD store.

The large box near the top of the tab displays the Windows 7 installations on the current computer. You see Current OS beside the Windows 7 installation you are running now; you see Default OS beside the Windows 7 installation that is set up as the default. There are four main tasks you can perform:

• Click the Set as Default button to set the highlighted Windows 7 install as the default for the Windows Boot Manager menu.

• Use the Timeout text box to set the maximum time that Windows Boot Manager waits before selecting the default OS.

• Use the check boxes in the Boot Options group to set the following startup options for the currently highlighted Windows 7 install:

  Safe Boot: Minimal— Boots Windows 7 in Safe mode, which uses only a minimal set of device drivers. Use this switch if Windows 7 won’t start, if a device or program is causing Windows 7 to crash, or if you can’t uninstall a program while Windows 7 is running normally.

  Safe Boot: Minimal (Alternate Shell)— Boots Windows 7 in Safe mode but also bypasses the Windows 7 GUI and boots to the Command Prompt instead. Use this switch if the programs you need to repair a problem can be run from the Command Prompt or if you can’t load the Windows 7 GUI.

  Note

  The shell loaded by the /safeboot:minimal(alternateshell) switch is determined by the value in the following Registry key:

  HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\SafeBoot\AlternateShell

  The default value is cmd.exe (the Command Prompt).

  
  

  Safe Boot: Active Directory Repair— Boots Windows 7 in Safe mode and restores a backup of the Active Directory service. (This option applies only to domain controllers.)

  Safe Boot: Network— Boots Windows 7 in Safe mode but also includes networking drivers. Use this switch if the drivers or programs you need to repair a problem exist on a shared network resource, if you need access to email or other network-based communications for technical support, or if your computer is running a shared Windows 7 installation.

  No GUI Boot— Tells Windows 7 not to load the VGA display driver that is normally used to display the progress bar during startup. Use this switch if Windows 7 hangs while switching video modes for the progress bar, or if the display of the progress bar is garbled.

  Boot Log— Boots Windows 7 and logs the boot process to a text file named ntbtlog.txt that resides in the %SystemRoot% folder. Move to the end of the file and you might see a message telling you which device driver failed. You probably need to reinstall or roll back the driver. Use this switch if the Windows 7 startup hangs, if you need a detailed record of the startup process, or if you suspect (after using one of the other Startup menu options) that a driver is causing Windows 7 startup to fail.

  Note

  %SystemRoot% refers to the folder into which Windows 7 was installed. This is usually C:\Windows.

  
  

  Base Video— Boots Windows 7 using the standard VGA mode: 640×480 with 256 colors. This is useful for troubleshooting video display driver problems. Use this switch if Windows 7 fails to start using any of the Safe mode options, if you recently installed a new video card device driver and the screen is garbled, the driver is balking at a resolution or color depth setting that’s too high, or if you can’t load the Windows 7 GUI. After Windows 7 has loaded, you can reinstall or roll back the driver, or you can adjust the display settings to values that the driver can handle.

  OS Boot Information— Displays the path and location of each device driver as it loads, as well as the operating system version and build number, the number of processors, the system memory, and the process type.

• Click the Advanced Options button to display the BOOT Advanced Options dialog box shown in Figure 4.3. You can set the following options:

  Number of Processors— In a multiprocessor system, specifies the maximum of processors that Windows 7 can use. Activate this check box if you suspect that using multiple processors is causing a program to hang.

  Maximum Memory— Specifies the maximum amount of memory, in megabytes, that Windows 7 can use. Use this value when you suspect a faulty memory chip might be causing problems.

  PCI Lock— Activate this check box to tell Windows 7 not to dynamically assign hardware resources for PCI devices during startup. The resources assigned by the BIOS during the POST are locked in place. Use this switch if installing a PCI device causes the system to hang during startup.

  Detect HAL— Activate this check box to force Windows 7 to detect the computer’s hardware abstraction layer (HAL) at startup. The HAL is a software layer that resides between the computer’s hardware and the operating system kernel, and its job is to hide hardware differences so that the kernel can run on a variety of hardware. If you force Windows 7 to detect the HAL, it can use the HAL to interact with the computer’s hardware at startup. This is useful if dealing with the hardware directly is causing startup problems.

  Debug— Enables remote debugging of the Windows 7 kernel. This sends debugging information to a remote computer via one of your computer’s ports. If you use this switch, you can use the Debug Port list to specify a serial port, IEEE 1394 port, or USB port. If you use a serial port, you can specify the transmission speed of the debugging information using the Baud Rate list; if you use an IEEE 1394 connection, activate Channel and specify a channel value; if you use a USB port, type the device name in the USB Target Name text box.

Using BCDEDIT to Customize the Startup Options

The System Configuration utility makes it easy to modify BCD store items, but it doesn’t give you access to the entire BCD store. For example, the Boot tab doesn’t list any legacy boot items on your system, and there are no options for renaming boot items or for changing the order in which the boot items are displayed in the Windows Boot Manager menu. For these tasks, and indeed for every possible BCD task, you need to use the BCDEDIT command-line tool.

Note that BCDEDIT is an administrator-only tool, so you must run it under the Administrator account (not just any account in the Administrators group). The easiest way to do this is to elevate your privileges when running the Command Prompt, as described in the following steps:

Table 1 summarizes the switches you can use with BCDEDIT.

To help you understand how BCDEDIT works, let’s examine the output that appears when you run BCDEDIT with the /enum switch:

Windows Boot Manager
--------------------
identifier              {bootmgr}
device                  partition=\Device\HarddiskVolume1
description             Windows Boot Manager
locale                  en-US
inherit                 {globalsettings}
default                 {current}
resumeobject            {53c701aa-e1c3-11dd-9af1-8cfcc639165e}
displayorder            {ntldr}
                        {current}
toolsdisplayorder       {memdiag}
timeout                 30
Windows Legacy OS Loader
------------------------
identifier              {ntldr}
device                  partition=\Device\HarddiskVolume1
path                    \ntldr
description             Earlier Version of Windows

Windows Boot Loader
-------------------
identifier              {current}
device                  partition=C:
path                    \Windows\system32\winload.exe
description             Windows 7
locale                  en-US
inherit                 {bootloadersettings}
recoverysequence        {53c701ac-e1c3-11dd-9af1-8cfcc639165e}
recoveryenabled         Yes
osdevice                partition=C:
systemroot              \Windows
resumeobject            {53c701aa-e1c3-11dd-9af1-8cfcc639165e}
nx                      OptIn

					  

As you can see, this BCD store has three entries: one for Windows Boot Manager, one for a legacy Windows install, and one for a Windows 7 install. Notice that each entry has an Identifier setting, and these IDs are unique to each entry. All IDs are actually 32-digit globally unique identifiers (GUIDs), but by default BCDEDIT works with a collection of well-known identifiers, including the following (type bcdedit id /? to see the complete list):

If you want to see the full GUIDs for every entry, add the /v (verbose) switch:

bcdedit /enum /v

It would take dozens of pages to run through all the BCDEDIT switches, so I’ll just give you a few examples so you can get a taste of how this powerful utility operates.

Making a Backup Copy of the BCD Store

Before you do any work on the BCD store, you should make a backup copy. That way, if you make an error when you change something in the BCD, you can always restore the backup copy to get your system back to its original state.

You create a backup copy using the /export switch. For example, the following command backs up the BCD store to a file named bcd_backup in the root folder of the C: drive:

bcdedit /export c:\bcd_backup

If you need to restore the backup, use the /import switch, as in this example:

bcdedit /import c:\bcd_backup

Renaming an Entry

The names that Windows Boot Manager assigns to the boot applications leave a lot to be desired. For a legacy operating system entry, for example, the default Earlier Version of Windows is not particularly descriptive. A simpler name such as Windows XP Pro would be much more useful. Similarly, all Windows 7 installs get the same name: Windows 7, which can be quite confusing. Names such as Windows 7 Home Premium and Windows 7 Ultimate would be much more understandable.

To rename an entry using BCDEDIT, use the following syntax:

bcdedit /set {id} description "name"

Here, replace id with the entry identifier (the GUID or the well-known identifier, if applicable) and replace name with the new name you want to use. For example, the following command replaces the current name of the legacy operating system entry (ntldr) with Windows XP Pro:

bcdedit /set {ntldr} description "Windows XP Pro"

Changing the Order of the Entries

If you’d prefer that the Boot Manager menu entries appear in a different order, you can use BCDEDIT’s /displayorder switch to change the order. In the simplest case, you might want to move an entry to either the beginning or the end of the menu. To send an entry to the beginning, include the /addfirst switch. Here’s an example:

bcdedit /displayorder {a8ef3a39-a0a4-11da-bedf-97d9bf80e36c} /addfirst

To send an entry to the end of the menu, include the /addlast switch instead, as in this example:

bcdedit /displayorder {current} /addfirst

To set the overall order, include each identifier in the order you want, separated by spaces:

bcdedit /displayorder {current} {a8ef3a39-a0a4-11da-bedf-97d9bf80e36c} {ntldr}