Selecting a SUSE Linux 10 boot loader

Figure 1-17

Linux enterprise systems typically use one of two boot loaders, LILO (Linux Loader) or GRUB (Grand Unified Boot Loader). Both are very powerful and flexible, and are controlled by easily edited configuration files (/etc/lilo.conf and /etc/grub.conf, respectively). The key difference between the two boot loaders is how they interact with these configuration files. If you use LILO and update its configuration file, you must rerun the lilo command to update the system boot information that is stored on your disk. GRUB automatically rereads its configuration file whenever you boot your system and therefore does not require that you update any other system boot information.

A few years ago, the general consensus was to move away from the LILO boot loader to the GRUB boot loader. GRUB provides a more robust boot loader, and the default configuration is fine for most users. If YaST detects a Windows installation, it adds this as a boot option, providing a means to dual-boot Windows and Linux on the same system.

YaST will already have configured your boot loader, depending on your system configuration. This also includes any Windows installations that have been found. To edit a boot loader entry, select the relevant entry and click Edit. You will be presented with the boot item configuration screen shown in Figure 1-18.

Figure 1-18

One of the most important reasons for editing the default boot loader configuration is to add a Linux kernel option at startup. If your hardware manufacturer has notified you that a certain value must be passed to the Linux kernel at boot time, you would append it to the "Other kernel parameters" section of the configuration dialog box. When you are happy with the boot loader item configuration, click OK to return to the boot loader overview screen.

A few very common kernel parameters that we have come across in recent years are noht and noacpi. Both of these parameters are relevant to modern machines. The first, noht, will turn off Linux's support of the Intel processor's hyperthreading feature. In certain processor-bound workloads, it is better to turn off hyperthreading to improve performance. The second, noacpi, turns off Linux's ACPI infrastructure. ACPI is the Advanced Configuration and Power Interface and is a standardized way for an operating system to control machine power, BIOS settings, and so on. In some situations ACPI actually stops Linux from booting on certain machines. Using the boot loader configuration to set these parameters enables you to control this before a system is installed.

When you make any changes that you want on the Boot Loader setup screen, click the Finish button to return to the standard YaST installer screen.

Customizing your SUSE Linux 10 installation

 Home: Introduction
 Step 1: Partitioning Your Disks
 Step 2: Resizing Existing Operating Systems Partitions
 Step 3: Primary and Extended Partitions
 Step 4: Defining Filesystems
 Step 5: The root partition
 Step 6: Data Partitions
 Step 7: Selecting Software for Installation
 Step 8: Selecting a Boot Loader
 Step 9: Changing the Default Runlevel