Red Hat ENTERPRISE LINUX 5.1 - LINUX ORACLE Tuning Manual page 14

Chapter 3. Kernel Upgrades
initrd /initrd-2.4.21-32.0.1.ELsmp.img
In this example, the "default" attribute is set to "0" which means that the
2.4.21-32.0.1.ELhugemem kernel will be booted. If the "default" attribute would be set to
"1", then 2.4.21-32.0.1.ELsmp would be booted. After you installed the newer kernel reboot the
system. Once you are sure that you do not need the old kernel anymore, you can remove the old
kernel by running:
# rpm -e <OldKernelVersion>
When you remove a kernel, you do not need to update /etc/grub.conf.
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