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Kernel re-compile is required in order to make the kernel very lean and which will result in FASTER operating system . It is also required to support any new devices. Note: Below 'bash#' denotes the bash prompt, you should type the commands that appear after the 'bash#' prompt. Below are commands tested on Redhat Linux, but it should work for other distributions with very minor changes.
bash$ su - root bash# cd /mnt/cdrom/RedHat/RPMS bash# rpm -i kernel-headers*.rpm bash# rpm -i kernel-source*.rpm bash# rpm -i dev86*.rpm bash# rpm -i bin86*.rpm
bash# man startx bash# startx bash# cd /usr/src/linux bash# make xconfig
bash# make menuconfig If the above command fails then try - bash# make config
bash# rpm -i /mnt/cdrom/Redhat/RPMS/modutils*.rpm bash# man lsmod bash# man insmod bash# man rmmod bash# man depmod bash# man modprobe
bash# make dep bash# make clean
bash# gvim -R /usr/src/linux/arch/i386/config.in bash# man less bash# less /usr/src/linux/arch/i386/config.in Type 'h' for help and to navigate press i, j, k, l, h or arrow, page up/down keys.
bash# cd /usr/src/linux bash# man nohup bash# nohup make bzImage & bash# tail -f nohup.out (.... to monitor the progress) This will put the kernel in /usr/src/linux/arch/i386/boot/bzImage bash# man tail
bash# cp /usr/src/linux/arch/i386/boot/bzImage /boot/bzImage.myker.26mar2001 bash# man lilo bash# man lilo.conf And edit /etc/lilo.conf file and put these lines - image=/boot/bzImage.myker.26mar2001 label=myker root=/dev/hda1 read-only You can check device name for 'root=' with the command - bash# df /
bash# lilo bash# lilo -q
bash# cd /usr/src/linux bash# make bzdisk See also mkbootdisk - bash# rpm -i mkbootdisk*.rpm bash# man mkbootdisk
bash# cd /usr/src/linux bash# make modules bash# make modules_install bash# man insmod bash# insmod
The following mistake is commited very frequently by new users.
If your new kernel does not boot and you get -
Warning: unable to open an initial console Kernel panic: no init found. Try passing init= option to kernel
The kernel looks for the init command which is located in /sbin/init. And /sbin directory lives on the root partition. For details see -
bash# man init
When you boot kernel and system tries to load any modules and you get "Unresolved symbol : __some_function_name" then it means that you did not clean compile the modules and kernel. It is mandatory that you should do make clean and make the modules. Do this -
bash# cd /usr/src/linux bash# make dep bash# make clean bash# nohup make bzImage & bash# tail -f nohup.out (.... to monitor the progress) bash# make modules bash# make modules_install
If the kernel fails to load a module (say loadable module for network card or other devices), then you may want to try to build the driver for device right into the kernel. Sometimes loadable module will NOT work and the driver needs to be built right inside the kernel. For example - some network cards do not support loadable module feature - you MUST build the driver of the network card right into linux kernel. Hence, in 'make xconfig' you MUST not select loadable module for this device.
You can install default loadable modules with -
The step given below may not be required but is needed ONLY FOR EMERGENCIES where your /lib/modules files are damaged. If you already have the /lib/modules directory and in case you want replace them use the --force to replace the package and select appropriate cpu architecture.
For new versions of linux redhat linux 6.0 and later, the kernel modules are included with kernel-2.2*.rpm. Install the loadable modules and the kernel with
This will list the already installed package. bash# rpm -qa | grep -i kernel bash# rpm -U --force /mnt/cdrom/Redhat/RPMS/kernel-2.2.14-5.0.i686.rpm (or) bash# rpm -U --force /mnt/cdrom/Redhat/RPMS/kernel-2.2.14-5.0.i586.rpm (or) bash# rpm -U --force /mnt/cdrom/Redhat/RPMS/kernel-2.2.14-5.0.i386.rpm
This is only for old versions of redhat linux 5.2 and before. Boot new kernel and install the loadable modules from RedHat Linux "contrib" cdrom
bash# rpm -i /mnt/cdrom/contrib/kernel-modules*.rpm ....(For old linux systems which do not have insmod pre-installed)
After successfully building and booting the Linux kernel, you may be required to do these additional steps to make some of the devices to work with Linux. (The steps below were tested on Redhat Linux but should work with other distributions as well.)
Video card/Monitor configuration:
bash$ su - root bash# man Xconfigurator bash# /usr/bin/X11/Xconfigurator --help bash# /usr/bin/X11/Xconfigurator bash# /usr/bin/X11/Xconfigurator --expert
Sound card configuration:
bash$ su - root bash# man sndconfig bash# /usr/sbin/sndconfig
Network card configuration:
Configure Firewall and IP Masquerading : For Linux kernel version 2.4 and above, the firewall and IP Masquerading is implemented by NetFilter package. Hence in kernel config you should enable Netfilter and run the Firewall/IPMasq script. Download the scripts from Firewall-IPMasq scripts , main page of Netfilter is at http://netfilter.samba.org. Related materials at firewalling-matures and Netfilter-FAQ.
For kernel version below 2.4 you should install the firewall rpms from rpmfind.net or firewall.src.rpm.
Configuration of other devices: Refer to HOWTO docs relating to your devices at http://www.linuxdoc.org
Given below is a sample /etc/lilo.conf file. You should follow the naming conventions like ker2217 (for kernel 2.2.17), ker2214 (for kernel 2.2.14). You can have many kernel images on the same /boot system. On my machine I have something like:
boot=/dev/hda map=/boot/map install=/boot/boot.b prompt timeout=50 default=firewall image=/boot/vmlinuz-2.2.14-5.0 label=ker2214 read-only root=/dev/hda9 image=/boot/vmlinuz-2.2.17-14 label=ker2217 read-only root=/dev/hda9 #image=/usr/src/linux/arch/i386/boot/bzImage # label=myker # root=/dev/hda7 # read-only image=/boot/bzImage.myker.11feb2001 label=myker11feb root=/dev/hda9 read-only image=/boot/bzImage.myker.01jan2001 label=myker01jan root=/dev/hda9 read-only image=/boot/bzImage.myker-firewall.16mar2001 label=firewall root=/dev/hda9 read-only