Chapter 2. Boot Loaders
file is left out of the command, a user who knows the password is allowed to edit the current
configuration file.
For more information about securing GRUB, refer to the chapter titled Workstation Security in the
Red Hat Enterprise Linux Security Guide.
•
root ( device-type
for GRUB, such as
•
rootnoverify ( device-type
root partition for GRUB, just like the
•
timeout= integer
entry designated in the
•
splashimage= path-to-image
used when GRUB boots.
•
title group-title
load a kernel or operating system.
To add human-readable comments to the menu configuration file, begin the line with the hash mark
character (
).
#
2.8. LILO
LILO is an acronym for the LInux LOader and has been used to boot Linux on x86 systems for many
years. Although GRUB is now the default boot loader, some users prefer to use LILO because it is
more familiar to them and others use it out of necessity, since GRUB may have trouble booting some
hardware.
2.8.1. LILO and the x86 Boot Process
This section discusses in detail the specific role LILO plays when booting an x86 system. For a
detailed look at the overall boot process, refer to Section 1.2 A Detailed Look at the Boot Process.
LILO loads itself into memory almost identically to GRUB, with the exception that it is only a two
stage loader.
1. The Stage 1 or primary boot loader is read into memory by the BIOS from the MBR
primary boot loader exists on less than 512 bytes of disk space within the MBR. It only loads
the Stage 2 boot loader and passes disk geometry information to it.
2. The Stage 2 or secondary boot loader is read into memory. The secondary boot loader displays
the Red Hat Enterprise Linux initial screen. This screen allows you to select which operating
system or Linux kernel to boot.
3. The Stage 2 boot loader reads the operating system or kernel and
LILO determines which operating system to start, it loads it into memory and transfers control
of the machine to that operating system.
Once the Stage 2 boot loader is in memory, LILO displays the initial Red Hat Enterprise Linux screen
with the different operating systems or kernels it has been configured to boot. By default, if Red Hat
Enterprise Linux is the only operating system installed,
system has multiple processors, a
option appears for the multiple processor (SMP) kernel. If LILO is configured to boot other
linux
operating systems, those boot entries also appear on this screen.
2. For more on the system BIOS and the MBR, refer to Section 1.2.1 The BIOS.
device-number , partition )
, and mounts the partition.
(hd0,0)
device-number , partition )
root
— Specifies the interval, in seconds, that GRUB waits before loading the
command.
default
— Specifies the location of the splash screen image to be
— Specifies a title to be used with a particular group of commands used to
linux-up
command, but does not mount the partition.
is the only available option. If the
linux
option appears for the single processor kernel and a
— Configures the root partition
— Configures the
into memory. Once
initrd
19
2
. The
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