# mv vmlinuz vmlinuz-2.2.12

# mv System.map System.map-2.2.12

# cd /etc

Edit your lilo.conf to add a new entry

image = /boot/vmlinuz-2.2.12

label=oldlin

read-only

root=/dev/hda5

For a quick guide to compiling kernels, read Mayank Sarup's article on compiling the Linux kernel.

Now you are ready to configure the kernel settings and compile the kernel.

# make menuconfig

or

# make xconfig

to open the configuration tool. Try to compile support as modules as this ensures a smaller size of the kernel.

Finally, get a cup of coffee (the compile takes a long time) and sit back and watch as the kernel compilation proceeds,

# make install

This will compile the kernel, copy the vmlinuz/System.map into your /boot directory and update lilo.conf. The next time you boot, selecting Linux will boot you into kernel 2.4.x