View source for Compiling kernel 2.6.21

This is an example how to compile a Linux kernel. It has been tested for SUSE Linux 10.2 and kernel 2.6.21, but should work same or similar for every combination.

= Check prerequesites =
* Make sure you have a compiler installed
 yast -i gcc 

= Get the code =
* Download the kernel from ftp.kernel.org
 wget ftp://ftp.kernel.org/pub/linux/kernel/v2.6/linux-2.6.21.tar.bz2
* unpack the kernel
 bunzip linux-2.6.21.tar.bz2
* unpack the kernel for the second time
 tar xvf linux-2.6.21.tar

= Build it =
* configure the kernel
 cd linux-2.6.21
 make oldconfig
* answer some un-understandable questions
The sense of the step ''make oldconfig'' is to tell the kernel its configuration, e.g. which parts should be built as a module, which parts should not be built at all and the name of your special build. oldconfig takes over the settings from the running kernel that you can check with <tt>zcat /proc/config.gz</tt>. The settings for the new kernel are stored in the file ''.config''. E.g. a line <tt>CONFIG_LOCALVERSION="-thorsten"</tt> in .config would tell kernel 2.6.27 to call himself 2.6.27-thorsten.
* compile the kernel, '''note:''' on a two-CPU VMWare virtual machine with 2.4 GHz, this lasted 19m28.605s
 make -j4
* compile the drivers
 make -j4 modules

= Install it =
* install the drivers
 make modules_install
* install the kernel
 cp arch/''x86_64''/boot/bzImage /boot/vmlinuz-2.6.21
This will install the kernel for the ''x86_64'' architecture.
* prepare the initial ramdisk
 cp System.map /boot
 mkinitrd
This will build an initial ramdisk for all kernels contained in /boot.
* add an entry to the bootloader. Let's take grub's /boot/grub/menu.lst:
 title 2.6.21-selfcompiled
    root (hd0,0)
    kernel /boot/vmlinuz-2.6.21 root=/dev/sda1
    initrd /boot/initrd-2.6.21

= Newer kernels =
x86_64 and x86_32 were merged into the x86 folder.