Boot Loader Configuration


A software boot loader is used to start Red Hat Linux on your computer. It can also start other operating systems, such as Windows. If you are using a Red Hat Linux software boot loader (GRUB or LILO), it will be detected automatically.

On the Boot Loader Configuration Screen, your options are:

  • Update boot loader configuration — Choose this option to keep your current boot loader configuration (GRUB or LILO depending on what you have currently installed) and have updates applied.

  • Skip boot loader updating — Choose this option if you do not want to make any changes to your current boot loader configuration. If you are using a third-party boot loader, you will want to skip updating your boot loader.

  • Create new boot loader configuration — Choose this option if you want to create a new boot loader for your system. If you currently have LILO and want to switch to GRUB, or if you have been using boot diskettes to boot your Red Hat Linux system and want to use a software boot loader such as GRUB or LILO, you will want to create a new boot loader configuration (see Chapter 1 for more information).

Once you have made your selection, click Next to continue.

Creating a New Boot Loader Configuration

In order to boot the system without a boot diskette, you usually need to install a boot loader. A boot loader is the first software program that runs when a computer starts. It is responsible for loading and transferring control to the operating system kernel software. The kernel, in turn, initializes the rest of the operating system. The installation program provides two boot loaders for you to choose from, GRUB and LILO.

GRUB (GRand Unified Bootloader), which is installed by default, is a very powerful boot loader. GRUB can load a variety of free operating systems, as well as proprietary operating systems, with chain loading (the mechanism for loading unsupported operating systems by loading another boot loader, such as DOS or Windows). LILO (LInux LOader) is a versatile boot loader for Linux. It does not depend on a specific file system, can boot Linux kernel images from floppy diskettes and hard disks, and can even boot other operating systems. If you do not want to install GRUB as your boot loader, click Change boot loader. You can then choose to install LILO or choose not to install a boot loader at all.

If you already have a boot loader that can boot Linux and do not want to overwrite your current boot loader, or if you plan to boot the system using boot diskettes, choose Do not install a boot loader by clicking on the Change boot loader button.

Warning

If you choose not to install GRUB or LILO for any reason, you will not be able to boot the system directly, and you will need to use another boot method (such as a boot diskette). Use this option only if you are sure you have another way of booting the system!

Every bootable partition is listed, including partitions used by other operating systems. The partition holding the system’s root file system will have a Label of Red Hat Linux (for GRUB) or linux (for LILO). Other partitions may also have boot labels. If you would like to add or change the boot label for other partitions that have been detected by the installation program, click once on the partition to select it. Once it’s selected, you can change the boot label by clicking the Edit button. Select Default beside the preferred boot partition to choose your default bootable OS. You will not be able to move forward in the installation unless you choose a default boot image.

Note

The Label column lists what you must enter at the boot prompt, in nongraphical boot loaders, in order to boot the desired operating system. Once you have loaded the GRUB boot screen, use the arrow keys to choose a boot label or type e for edit. You will be presented with a list of items in the configuration file for the boot label you have selected. At the graphical LILO screen, press Ctrl-x to exit to the boot: prompt. If you forget the boot labels defined on your system, you can always press Tab at the prompt to display a list of defined boot labels.

Boot loader passwords provide a security mechanism in an environment where physical access to your server is available. If you are installing a boot loader, you should create a password to protect your system. Without a boot loader password, users with access to your system can pass options to the kernel that can compromise your system security. With a boot loader password in place, the password must first be entered in order to select any nonstandard boot options. If you choose to use a boot loader password to enhance your system security, be sure to select the checkbox labeled Use a boot loader password. Once it’s selected, enter a password and confirm it.

To configure more advanced boot loader options, such as changing the drive order or passing options to the kernel, be sure that Configure advanced boot loader options is selected before clicking Next.

Advanced Boot Loader Configuration

Now that you have chosen which boot loader to install, you can also determine where you want the boot loader to be installed. You may install the boot loader in one of two places.

The master boot record (MBR)

This is the recommended place to install a boot loader, unless the MBR already starts another operating system loader, such as System Commander. The MBR is a special area on your hard drive that is automatically loaded by your computer’s BIOS and is the earliest point at which the boot loader can take control of the boot process. If you install it in the MBR, when your machine boots, GRUB (or LILO) will present a boot prompt. You can then boot Red Hat Linux or any other operating system that you have configured the boot loader to boot.

The first sector of your boot partition

This is recommended if you are already using another boot loader on your system. In this case, your other boot loader will take control first. You can then configure that boot loader to start GRUB (or LILO), which will then boot Red Hat Linux.

If your system will use only Red Hat Linux, you should choose the MBR. For systems with Windows 9x, you should also install the boot loader to the MBR so that it can boot both operating systems. Click the Change Drive Order button if you would like to rearrange the drive order. Changing the drive order may be useful if you have multiple SCSI adapters or both SCSI and IDE adapters and want to boot from the SCSI device.

The Force LBA32 (not normally required) option allows you to exceed the 1024-cylinder limit for the /boot partition. If you have a system that supports the LBA32 extension for booting operating systems above the 1024-cylinder limit and you want to place your /boot partition above cylinder 1024, select this option. If you wish to add default options to the boot command, enter them in the Kernel parameters field. Any options you enter will be passed to the Linux kernel every time it boots.




Official Red Hat Linux Administrator's Guide
Official Red Hat Linux Administrators Guide
ISBN: 0764516957
EAN: 2147483647
Year: 2002
Pages: 278
Authors: Red Hat Inc

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