Mastering Boot.ini

[James Afflek]

Edit, modify and understand the functioning of the Boot.ini file.

Edit the Boot.ini

Understand the boot.ini file options:

Consider the boot.ini file to a computer that has installed two operating systems:

[boot loader] 
timeout = 30 
default = multi (0) disk (0) rdisk (0) partition (1) \ WINDOWS 
[operating systems] 
multi (0) disk (0) rdisk (0) partition (2) \ WINDOWS = "Windows Server 2003, Enterprise" / fastdetect 
multi (0) disk (0) rdisk (0) partition (1) \ WINDOWS = "Microsoft Windows XP Professional" / fastdetect

Some explanations:

• Timeout: Specifies the waiting time before the default operating system starts. In our example, the waiting time is 30 seconds.
• Default: Specifies the default operating system. Here, Windows XP Professional is the default.
• Multi (0) specify that the main controller is in charge of the drive.
• Disk (0): specifies the logical unit used.
• Rdisk (0) means the physical disk.
• Partition (1) means the partition number which is installed on the operating system.

Windows Server 2003 is installed on a partition D:, while the professional version of Windows XP takes the drive letter C:.


The parameters of Boot.ini useful for troubleshooting:

These options can be used if you suspect a memory card is defective, or solve a problem of resource allocation:

• / MAXMEM =: allows you to specify a memory which is less than actually installed. For example, if you have two strips of 64 megabytes, you can specify this parameter: / maxmem = 64.
• / Burnmemory = number: You can specify the maximum size that the system will be able to use. For example, / burnmemory = 128 would allow the system to use only 128 MB of RAM.
• / PCILOCK =: disable the automatic granting of the interrupt request by the system and apply those specified in the BIOS.

It is easier to check one of these options using the System Configuration Utility.

If the boxes are grayed out, try this trick:

• Click on Start / Run and type: regedit
• Open HKEY_LOCAL_MACHINE \ SOFTWARE \ Microsoft \ Shared Tools \ MSConfig \ state.
• Edit DWORD value named bootini.
• Enter data as the value of the number 1.

Edit the Boot.ini although that has more access to the Windows desktop:

Let's say we wanted to reduce the amount of memory (up to 128 MB of RAM) used to check if the problem is not a problem of memory. That is to add this parameter in the Boot.ini file:

multi (0) disk (0) rdisk (0) partition (1) \ WINDOWS = "Microsoft Windows XP Professional" / fastdetect / MAXMEM = 128

1. Start the Recovery Console.
2. Choose what Windows installation you want to start.
3. Enter possibly the Administrator password.
4. Enter this command: bootcfg / rebuild
5. Add the first installation detected by tapping the letter O.
6. Enter Load Identifier as follows: test
7. Enter the option of loading the operating system this: / maxmem = 128
8. Check the results by typing this: type c: \ boot.ini or more c: \ boot.ini and bootcfg / list
9. You normally have two lines with an entry to a restricted to 128 MB of RAM.
10. Restart your computer and select the entry that was added.

Once a localized problem go back to editing the Boot.ini file and then delete the entry from the menu that will become obsolete.

Setting DEP data (DEP):

DEP data (DEP) is a feature both in hardware (provided they have a compatible processor that enables the prevention of physical data) and software made by Service Pack 2 Microsoft Windows XP and prevents code execution in the areas of memory "protected". This prevents attacks caused by other viruses and that can execute lines of code from memory locations reserved for the operating system and programs "secure". The new processors can use the DEP data when the physical address extension is enabled. It's easy to control the Boot.ini to verify if this feature is enabled or not. There are two switches:

/ noexecute: DEP data is enabled.
/ execute the DEP data is disabled.
As a result of this switch, you can enter different values:
/ Noexecute = AlwaysOn: turn on DEP for the operating system and all processes. All attempts to disable this feature will be ignored.
/ Noexecute = optout: turn on DEP for all processes. Users can specify a list of applications that are not monitored.
/ Noexecute = optin: turn on DEP for the operating system. This is the default setting.
/ Noexecute = alwaysoff the DEP feature is disabled.

[James Afflek]

Solving a problem in the Boot.ini

I have twice the same operating system:
This followed a parallel installation of Windows XP. The problem is therefore false information in the boot.ini file. So when you start on a system, it's done as a letter in the mail while on the other you're in the installation process (after, for example, a file copy).

1. Click on Start / Run and type: msconfig
2. Select the Boot.ini tab and click Check boot paths.

Otherwise simply edit the boot.ini file (it is at the root of your disk).

1. With the right mouse button, click the file, then click the Properties command.
2. Uncheck the Read-only option, then click OK.
3. Double-click the file, which normally must be opened with Windows Notepad.

The file looks like this:

[boot loader] 
timeout = 30 
default = multi (0) disk (0) rdisk (0) partition (1) \ WINDOWS 
[operating systems] 
multi (0) disk (0) rdisk (0) partition (1) \ WINDOWS = "Microsoft Windows XP Professional" / fastdetect 
multi (0) disk (0) rdisk (0) partition (2) \ WINDOWS = "Microsoft Windows XP Professional" / fastdetect

Operating systems are listed according to the same order from top to bottom. Simply delete the redundant line, then save the changes and reboot.

"Invalid Boot.ini. Starting from c: \ windows":

Just edit the boot.ini file:

1. Open Windows Explorer and enable the display of files and hidden folders. The file is located at the root of your drive.
2. With the right mouse button, click the file, then click the Properties command.
3. Uncheck the Read-only option, then click OK.
4. Double-click the file, which normally must be opened with Windows Notepad.

The file looks like this:

[boot loader] 
timeout = 30 
default = multi (0) disk (0) rdisk (0) partition (1) \ WINDOWS 
[operating systems] 
multi (0) disk (0) rdisk (0) partition (1) \ WINDOWS = "Microsoft Windows XP Professional" / fastdetect

In the worst case, you just have to create from scratch:

1. With the right mouse button, click an empty part of the Windows Explorer and select New / Text Document.
2. Copy word for word the text, possibly by making the necessary adjustments, and then save the file.
3. You will get a file named New Document texte.txt.
4. Select it, then press the F2 key on the keyboard.
5. Enter the new name: boot.ini.

Yes confirm the warning message from Windows: "Do you really want to change the extension?" All you have to restart your computer.