Datasheet

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Chapter 1 ✦ Installing SUSE 10
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 noti-
fied 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 dia-
log 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 fea-
ture. 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 situ-
ations 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.
Changing the Default Runlevel
Runlevels are discussed in detail in Chapter 4. As a quick summary, a system’s
runlevel determines the services that are automatically started when your system
boots. The YaST Expert Installation Settings screen can be used to change the
default runlevel of the system by clicking the Default Runlevel heading in YaST’s
Installation Settings panel or by clicking the Change button and selecting Default
Runlevel from the pop-up menu.
As you can see in Figure 1-19, you can choose to boot your SUSE system in a variety
of different ways: without networking functionality (runlevel 2), multiuser with net-
work (runlevel 3), or multiuser with X Windows (runlevel 5). The default runlevel in
a standard installation is runlevel 5, multiuser with X Windows. You should keep
this as your default runlevel unless you have a specific reason to change it.
When you make any changes that you want to your system’s default runlevel, click
OK to set the selected runlevel as your system default. The Set Default Runlevel
pop-up closes, and YaST’s Installation Setting panel displays.
Note
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