Question : How to download a new kernel ?

Hello group,

I'm new to Linux Kernel and have started readin a book written by Robert Love. In the book it is recommended to start with the latest version so our network admin has installed RedHat Enterprise 5 for me. Of course, I have root access to this machine but what I need to know is:

1) How can I download the latest kernel and its source file on this machine using a tool like yum or rpm?
2) Under /usr/src/ I have to directories 1)Linux         2)RedHat
     Which one should I consider as path for Kernel and its source?

Your help will be appreciated greatly.

Regards,
ak

Answer : How to download a new kernel ?

Before you do anything, you should check that the file you have received is complete. Do an "ls -l" of it to make sure it is the expected size. If that looks OK, do

bzip2 -t linux-2.6.22.3.tar.bz2

to test the integrity of the archive.

As regards the directories in /usr/src: leave both alone and create a new one. The bz2 file does not itself belong in /usr/src (at least I don't think it does) - on my system I have created a /usr/gz directory where I store retrieved zipped files (.bz2. .gz, .tgz, .zip &c.). Let's say you do the same: so you mkdir /usr/gz and mv linux-2.6.22.3.tar.bz2 from wherever it is now to /usr/gz/. You now have the file /usr/gz/linux-2.6.22.3.tar.bz2. Next do:

cd /usr/src
cat  /usr/gz/linux-2.6.22.3.tar.bz2 | bzip2 -d | tar -xf  -

or mosre simply if you have a new enough tar then replace the 2nd line above with

tar -xjf /usr/gz/linux-2.6.22.3.tar.bz2

This will create the new directory /usr/src/linux-2.6.22. It is not strictly necessary, but I like to symlink the current source to linux: while still cd'd to /usr/src I would next do

rm -f linux
ln -s linux-2.6.22.3 linux

The rm is not needed the very first time as you are doing but you'll want to do it next time believe me. So get into the habit .
Next you will need to configure the kernel before building it. Don't do this just yet, but the commands to configure are:

cd /usr/src/linux
make xconfig

Before configuring the kernel, you want to put the current configuration into /usr/src/linux so that make xconfig has somewhere to start from. Your 2.6.15 config is some way back from what you're now building so there will be a stack of warnings when you use it but don't worry - they're only warnings and the old config will provide some useful information to the configurator.
The file you want to install is /usr/src/linux/.config. As I posted to your other Q, you can hopefully make that file by:

cd /usr/src/linux
cat /proc/config.gz >.config

If that doesn't work (because storing of config was not configured), then you'll probably find the config for your system somewhere under /usr/src/kernels. Be sure in that case to configure storing of the config in future (it's under "General setup" near the top of the menu when you run "make xconfig").
You are now ready to run make xconfig as above. You'll get a GUI called qconf (because it uses the Qt library) - work through the options and adjust as you need. If you have SATA you'll certainly have to do something - the way SATA is configured changed dramatically between 2.6.15 and 2.6.20. When I did an xconfig for a (paying) client, I also removed a lot of modules that we agreed he'd never want: there should be no performance impact in leaving them but it wastes disk space and makes the build take longer. Perhaps as this is your first build you might want to leave them alone for now.
Something you actually might want to do is remove the initrd stuff because it's not IMHO especially well documented how to replicate it in a custom build. initrd (INITial Ram Disk) is a great mechanism for distributors because a small kernel will load on almost any hardware and use required modules at boot time, but on a customised build you simply don't need it. Just make sure that the drivers (configurable items) used by the disk you're going to boot off are built as part of the kernel (GUI box has a tick) tather than as a module (GUI box has a dot).

Post again one you get through the above.