 
|
 |
 Rethinking the Datacenter
Sponsored by HP
Today's datacenters need to increase utilization, get control over power and cooling costs, and align with business objectives. Download this eBook to learn about the challenges facing the data center in a world where digital information is growing at a torrid pace and costs are being held in check. Learn more. »
|
|
Putting the Green into IT
Sponsored by HP
Electricity use in data centers is skyrocketing, sending energy bills through the roof, creating environmental concerns and generating negative publicity. "Going Green" means looking to technologies like virtualization, energy-efficient chips and racks, and implementing policies that extend beyond the data center. Learn more. »
|
|
Managing the Modern Network
Sponsored by HP
In a global economy where information crosses the globe in an instant, and where Web-based applications power business, it's more important than ever to ensure your network is safe from threats and optimized to deliver the data your business needs. »
|
|
Evaluating Software as a Service for Your Business
Sponsored by Webroot
Is Software as a Service just hype, or is something really going on here? See if your company can benefit as SaaS tries to change the face of the enterprise.
»
|
|
Is Your Disaster Recovery Plan Good Enough?
Sponsored by HP
Preparing for a disaster is more often than not part of the storage planning process, and it is one of the most difficult tasks, since it includes local hardware and software, networking equipment, and a test plan. Learn how to get disaster recovery right. »
|
 |
How to Compile the Linux Kernel
James Andrews
Saturday, May 29, 1999 01:36:47 PM
Introduction
RedHat is not Linux, it is a distribution based on the Linux kernel. The Linux kernel is a complex program which provides the underlying services to the rest of a Linux distribution. But it is easy to add new features or improvments to it as, unlike commercial operating systems like Windows 95 or MacOS, the source code is freely available. It is common practice with a Linux based operating system to recompile the kernel from source and much effort has been put in to make this a realitively user-friendly experience. Why Compile a New Kernel?
You may be thinking "But why recompile it? It works fine as it is." There are three reasons for a recompile. Firstly, you may have some hardware that is so new that there's no kernel module for it in on your distribution CD. Secondly, you may have come across some kind of bug which is fixed in a revision of the operating system. Lastly, you may have some new software which requires a newer version of the operating system. Getting the Kernel Sources
The most recent releases of the kernel sources are available on ftp.kernel.org. This site is mirrored worldwide so there is probably a fast copy of it somewhere near you. Locate the file for the latest version of the operating system and download it to /usr/src. Then issue the tar zxf command to unpack it. Alternatively, if you already have the kernel sources and only need to upgrade one version number (from 2.2.1 to 2.2.2 for instance) then download the patch file to /usr/src and then use the command: gzip -dc patch-2.2.2.gz |patch -p0 to upgrade your old kernel sources. Patch files are much smaller to download than the whole thing. |
If you do not need the very latest version, then installing a kernel source package from your distribution CD may be an easier way to proceed.
Configuring For a Build
Change directory to /usr/src/Linux and issue the command:make menuconfig
This will build a few programs and then quickly pop up a window. The window menu lets you alter many aspects of kernel configuration.
After you have made any necessary changes, save the configuration and follow these instructions--do a
make dep; make clean
The first of these commands builds the tree of interdependencies in the kernel sources. These dependencies may have been affected by the options you have choosen in the configure step. The make clean purges any now-unwanted files left from previous builds of the kernel.
Then you are ready to go! Issue this command:
make zImage
and then, if you are on a machine slower than a Pentium 200, go and make a cup of tea. This takes about 20 minutes on a Pentium 90...the kernel has a lot of source code as you may have noticed when downloading it. When this is complete do a:
make modules
This will not take as long.
Installing a New Kernel
Phew, finally! The last step is installing the new kernel. On an Intel-based system the kernel is installed to the right place in /boot with the command cp /usr/Linux/src/arch/i386/boot/zImage /boot/newkernel
then
make modules_install
This will install the modules in /lib/modules. Next, edit /etc/lilo.conf to add a section like this
image = /boot/newkernel
label = new
read-only
At the next reboot, select the kernel 'new' in lilo, and it will load the new kernel. If it works fine, move it to the first position in the lilo.conf so it will boot every time by default.
Summary
Compiling the kernel is a relatively simple operation- if you have done it before! At first it can seem daunting. There are many Web sites dedicated to the kernel; at the left are just a few.
Rethinking the Datacenter
Putting the Green into IT
Managing the Modern Network
Evaluating Software as a Service for Your Business
Is Your Disaster Recovery Plan Good Enough? 
