The next item you can change in your SUSE Linux 10 installation is the configuration of the boot loader. A boot loader is central to the deployment of Linux enterprise as it controls the booting of operating systems on the PC. To customize the boot loader that is used by your SUSE Linux 10 installation, you must click the Booting heading in YaST's Expert Installation Settings panel, or click the Change button (under the Expert Tab) and select Booting from the popup menu. Doing either of these displays the pane shown in Figure 1-17, YaST's Boot Loader Settings screen.
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.
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
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
The above tip is excerpted from from Chapter 1, "Installing SUSE 10" our original excerpt of The SUSE Linux 10 Bible by Justin Davies, courtesy of Wiley Publishing. This chapter explains how to successfully install SUSE Linux 10 on your box. Find it helpful? Buy it on Amazon.