Installation guide

208 Chapter 23. Upgrading the Kernel
If you plan to upgrade the kernel-source, kernel-docs, or kernel-utils packages, you
probably do not need to keep the older versions. Use the following commands to upgrade
these packages (the versions might vary):
rpm -Uvh kernel-source-2.4.18-0.12.i386.rpm
rpm -Uvh kernel-docs-2.4.18-0.12.i386.rpm
rpm -Uvh kernel-utils-2.4.18-0.12.i386.rpm
If you are using PCMCIA (for example, a laptop), you also need to install the kernel-
pcmcia-cs and keep the old version. If you use the -i switch, it will probably return a
conflict because the older kernel needs this package to boot with PCMCIA support. To work
around this, use the --force switch as follows (the version might vary):
rpm -ivh --force kernel-pcmcia-cs-3.1.24-2.i386.rpm
If you are using the ext3 file system or a SCSI controller, you need an initial RAM disk. The
purpose of the initial RAM disk is to allow a modular kernel to have access to modules that
it might need to boot from before the kernel has access to the device where the modules
normally reside.
The initial RAM disk is created by using the mkinitrd command. However, the Red Hat
kernel RPM package performs this step for you. To verify that it was created, use the com-
mand ls -l /boot. You should see the file initrd-2.4.18-0.12.img (the version should
match the version of the kernel you just installed).
Now that you have installed the new kernel, you need to configure the boot loader to boot
the new kernel. Refer to Section 23.5 for details.
23.5. Configuring the Boot Loader
The kernel RPM package configures the GRUB or LILO boot loader to boot the newly in-
stalled kernel if either boot loader is installed. However, it does not configure the boot loader
to boot the new kernel by default.
It is always a good idea to confirm that the boot loader has been configured correctly. This is
a crucial step. If the boot loader is configured incorrectly, you will not be able to boot your
system. If this happens, boot your system with the boot diskette you created earlier and try
configuring the boot loader again.
23.5.1. GRUB
If you selected GRUB as your boot loader, confirm that the file /boot/grub/grub.conf con-
tains a title section with the same version as the kernel package you just installed (if you
installed the kernel-smp and/or kernel-bigmem, you will have a section for it has well):
# NOTICE: You have a /boot partition. This means that
# all kernel paths are relative to /boot/
default=0
timeout=30
splashimage=(hd0,0)/grub/splash.xpm.gz
title Red Hat Linux (2.4.18-0.12)
root (hd0,0)
kernel /vmlinuz-2.4.18-0.12 ro root=/dev/hda3
initrd /initrd-2.4.18-0.12.img
If you created a separate /boot partition, the paths to the kernel and initrd image are relative
to the /boot partition.