Booting Linux with the Win 2k Boot Loader

Tired of typing boot labels at LILO to get into Windows 2000? Here’s how to get Linux as an option in the Win 2k boot menu

Tuesday, August 01, 2000

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Booting up a PC is a complex process. When a PC starts up, instructions in the BIOS make it look at the first sector (Sector #0) of the primary hard disk, assuming that the primary hard disk is the first boot device, and loads the data residing there into memory. The data consists of the partition table and the Master Boot Record (MBR). The MBR contains a small, but important program called the Master Boot Code (MBC). This contains instructions on where to find the rest of the operating system—that is, the location of the rest of the OS on the physical hard disk. This address is nothing but the partition on which the rest of the operating system kernel resides. Once the MBC points to the correct location, the BIOS starts executing the code for the OS from there.

Every operating system has its own MBC. The code can be a simple set of instructions that point to one particular location, like in DOS or Win 9x; or a more interactive one that presents a menu of selections or allows you to type in a command, like the ones in Win NT/2000 and Linux. Every time you install a new operating system, it overwrites the current MBR with its own MBC that points to the new OS.

If you’ve installed Linux while retaining an existing Windows installation, you know you can switch between the Windows and Linux OSs by typing in the correct label at the LILO: prompt. For example, if your Windows installation was named "dos" (which it is by default), type in "dos" at the LILO: prompt and you can boot into Windows without any problem. This is nothing but the Linux boot loader at work.

However, for those of you who’ve used Win NT/2000, you have a different boot loader. NT shows a menu of currently installed operating systems and lets you switch between them by using the arrow keys and pressing "Enter" on the highlighted choice. Win 2000 doesn’t show you a list of choices by default, although you have the option to see if you wish.

If you’re only an occasional user of Linux, playing around and experimenting during your free time, but use NT/2000 much more often, you’d like to have Linux on the NT boot menu rather than the other way around. Unfortunately, this doesn’t recognize the Linux boot partition at all. So we’ll have to do some tweaking to get this to work.

This article will show you how to get Linux as an option in the Win 2000 boot menu under three different configurations—when Win 2000 is already installed and you want to install Linux, when Linux is already installed and you want to install Win 2000, and finally when both are installed and LILO is the boot loader. Most of these instructions should work with NT 4 too, but haven’t been tested with it.

Windows 2000 installed

This is the configuration that might be most common. Here, I assume you have enough unpartitioned space left on the drive to install Red Hat Linux 6.2 given on the PC Quest June 2000 CD, and that you know how to install Linux as well as Windows 2000.

First, create an Emergency Boot Disk for your Win 2000 installation by going to Start>Programs>Accessories>System Tools>Backup and clicking the Emergency Repair Disk. Insert a new, blank floppy when prompted. You should always do this.

Now boot off the PCQ Red Hat 6.2 CD and start the install process as usual. When you reach Disk Druid, don’t touch the Win 2000 partition(s). Simply add as many partitions as you want for the Linux install on the remaining free space. Continue till the point where you’re asked where to install LILO, the Linux boot loader.

The next two steps are very important. Don’t choose the Master Boot Record in this step; instead choose the first sector of the root partition. And when prompted to create a Boot Disk, do so. I can’t stress this point enough. Create the Boot Disk right now, or you may not be able to access your Linux installation without reinstalling it.

Once the Linux installation is complete, let the system reboot. If you’ve followed the instructions correctly, you should be booting into Win 2000 as usual, as if there were no Linux around. Put in the Linux boot floppy and reboot. This will show you the LILO prompt. Press "Enter" and get into your Linux installation.

Now take a look at /etc/lilo.conf. This is the boot configuration file that contains the name of the partition that holds the boot information. Look for a line that says: boot=/dev/hdxy. This line informs the OS loader which device to use for booting up. The "hd" stands for hard disk, the "x" is the physical device on your system and the "y" is the partition number on that physical device. So, if your Linux boot partition was on the third partition of your first hard disk, your boot device would be /dev/hda3. If it were on the second partition of the second physical hard disk, it would be /dev/hdb2.

After you make a note of the correct device, su as root and issue the following command:

dd if=/dev/hdxy of=/tmp/LiloBoot. bin bs=512 count=1

Remember to change the hdxy to the entry in your lilo.conf. This line creates a 512-byte file called LiloBoot.bin in the
/tmp directory (you can name this file anything you want). Copy this file to a DOS floppy using mcopy or by mounting it. Reboot into Win 2000 now.

Copy the Liloboot.bin file to the C:\ folder and make its attributes Read-Only and Hidden. Now open a command prompt and give the command:

attrib –r –s –h c:\boot.ini

After this, open the boot.ini file in Notepad. You should see a few lines similar to this:

[boot loader]

timeout=30

default=multi(0)disk(0)rdisk(0) partition(1)\WINNT

[operating systems]

multi(0)disk(0)rdisk(0)partition(1)\ WINNT="Microsoft Windows 2000 Professional" /fastdetect

Add a line to the end of the file, which looks like this:

c:\LiloBoot.bin="PCQ RedHat Linux 6.2 (Kernel 2.2.14-12)".

The first part specifies which file to use for booting and the second part is the label in the menu. You can use whatever you feel like here. Save the boot.ini file and reset its default attributes to Read-Only, Hidden, and System.

Boot your PC again, and see the label entry you made appear in the Win 2000 boot menu. Select it and press "Enter". You should immediately see the LILO prompt. Continue as you would normally.

Linux pre-installed

If you have a system where Linux has already been installed and you wish to install Win 2000 in some unpartitioned space, it isn’t much of a problem. Make sure you have a boot disk handy for Linux. If not, create one using the mkbootdisk command. Assuming you’re using the PCQ June 2000 Red Hat installation (Kernel 2.2.14-12) use the following command, with a floppy in the drive:

mkbootdisk –-device /dev/fd0 2.2.14-12

Open /etc/lilo.conf in your favorite editor and look for the line that says boot=/dev/hda. This line is the one that says where the boot loader is installed (hda is the MBR). Change this to the partition where the /boot is installed. This is again a very important step. To see which partitions exist, run the fdisk command and type "p" to view the partition table. Note the partition where /boot is installed (not /, unless you installed everything on a single partition) and enter that in lilo.conf. For example, if your /boot is installed on /dev/hda3, lilo.conf should have the entry boot=/dev/hda3. Save the file and issue the command lilo –v. This will write the new LILO.

Now install Win 2000 normally and it’ll overwrite LILO. You can boot into Win 2000 and play around. To get the Linux menu option, boot into Linux using the boot floppy and create the disk image for Windows using dd as given in the previous part. The remaining steps are the same to install the menu.

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