LinuxQuestions.org
Review your favorite Linux distribution.
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Software > Linux - Kernel
User Name
Password
Linux - Kernel This forum is for all discussion relating to the Linux kernel.

Notices


Reply
  Search this Thread
Old 10-10-2007, 04:52 AM   #1
tkmsr
Member
 
Registered: Oct 2006
Distribution: Ubuntu,Open Suse,Debian,Mac OS X
Posts: 798

Rep: Reputation: 39
creating vmlinuz and initrd on distribution media


I am trying to learn to create the vmlinuz and initrd that are shipped on installation DVD of Fedora like FC6,FC3 Suse etc etc or any other linux distribution. Which when loaded by isolinux and after asking for options starts installation on a system
1) What should I look into any specific documentation
2) how does it work without system.map file
3) how are these kernel and initrd different from the ones found in /boot
folder of a system in which linux is installed that are specific to a
particular system and load only the specific drivers .If they are not
different then how can I use these kernels and initrd to replace the
one on distribution media supplied by a linux vendor.
 
Old 10-10-2007, 11:55 PM   #2
sundialsvcs
LQ Guru
 
Registered: Feb 2004
Location: SE Tennessee, USA
Distribution: Gentoo, LFS
Posts: 9,078
Blog Entries: 4

Rep: Reputation: 3170Reputation: 3170Reputation: 3170Reputation: 3170Reputation: 3170Reputation: 3170Reputation: 3170Reputation: 3170Reputation: 3170Reputation: 3170Reputation: 3170
Ummm... that's an awful lot of questions. And I think that the very best place to begin my answer is with a bit of explanation, which might help you to "reposition" your original question..

...

The good folks who build those terrific "Linux distros" for all of us, face one essential problem: they have no idea what sort of hardware we might be running. And unfortunately, by the time that "the Linux kernel" is up-and-running, those sorts of issues need to have been sorted out!

So, the initrd ("initial RAM-disk") mechanism was conceived as a sort of "in-between moment" during which such decisions can be made.
  1. The Linux kernel will boot, but initially it will do so only to the point where it can "mount" a "compressed floppy-disk(!!)" which is the initrd.
  2. The initrd will now, in a primitive and "bare bones" environment, determine which kernel-modules need to be loaded to support the current hardware, and will load them.
  3. When initrd has finished, the Linux system will boot.
On some systems, such as Knoppix, the initrd stage really does have "true investigative responsibilities." On others, the installer-program merely determines in-advance what initrd must do and then builds an initrd image that "does exactly that."
 
Old 10-11-2007, 12:00 PM   #3
tkmsr
Member
 
Registered: Oct 2006
Distribution: Ubuntu,Open Suse,Debian,Mac OS X
Posts: 798

Original Poster
Rep: Reputation: 39
Quote:
Originally Posted by sundialsvcs View Post
which might help you to "reposition" your original question..."
I would like to know how to reposition my question I have been asking on many forums but did not yet made myself clear.

...

Quote:
in a primitive and "bare bones" environment, determine which kernel-modules need to be loaded to support the current hardware, and will load them.[*] When initrd has finished, the Linux system will boot.[/list]On some systems, such as Knoppix, the initrd stage really does have "true investigative responsibilities." On others, the installer-program merely determines in-advance what initrd must do and then builds an initrd image that "does exactly that."
want to know more about "bare bones" environment and true investigative responsibilities.
 
Old 10-17-2007, 04:48 AM   #4
tkmsr
Member
 
Registered: Oct 2006
Distribution: Ubuntu,Open Suse,Debian,Mac OS X
Posts: 798

Original Poster
Rep: Reputation: 39
I think I have got a bit of answer the kernel image and initrd that I said on installation DVD is generic kernel image which is used for installations
http://www.gentoo.org/doc/en/handboo...?part=1&chap=7
control f with option generic

I need to build a generic CD as image or compile a generic kernel
http://linuxfromscratch.org/pipermai...ry/026055.html
 
Old 10-24-2007, 02:13 PM   #5
tkmsr
Member
 
Registered: Oct 2006
Distribution: Ubuntu,Open Suse,Debian,Mac OS X
Posts: 798

Original Poster
Rep: Reputation: 39
Quote:
Originally Posted by tkmsr View Post

My question is what is the difference between the kernel images that are on the installation media inside openSUSE-10.2-GM-DVD-i386.iso/boot/i386/loader/
(name linux and initrd )

and the kernel images that are on the system after a fresh installation has taken place inside /boot/ folder
which was able to boot the system instead of starting installation

Ok so I got what was actually I was searching for I am posting this as a reference if some one by mistake read this and is willing to do same as I did with some other distribution after reading this link go here
http://www.linuxquestions.org/questi...=1#post2935301

you copy the initrd from the distribution DVD and the one on your boot folder inside the system
and do as root
gzip -dc initrd | cpio -id
you will see a lot of directories and some executables
do this for both the initrd's the one on boot folder and the one in installation media
the difference comes in
modules which they load
I am not sure about the udev or devfs which the initrd on installation cd or dvd does .
Actually the difference comes in the init script which you see for both the initrd's the init extracted from the initrd of installation cd or dvd
has a linuxrc script which starts installaion by calling the installer which in my case was yast and in case of fedora is anaconda and debian has its own.
I have tried to explain what ever possible now this should help you.
 
  


Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off



Similar Threads
Thread Thread Starter Forum Replies Last Post
Is it possible to update the pxe network install initrd.img and vmlinuz ? lets-eat-gary Fedora 1 08-22-2006 05:54 AM
How to update the pxe network install initrd.img and vmlinuz ? lets-eat-gary Linux - Networking 3 08-20-2006 04:45 PM
Creating an initrd? raid517 Linux - Software 4 04-04-2005 10:26 AM
how to encrypt initrd.img and decrypt in vmlinuz. AshesOfTime Programming 1 12-09-2004 04:48 PM
booting vmlinuz/initrd from a bootloader bob_man_uk Linux - General 4 04-07-2004 10:47 PM

LinuxQuestions.org > Forums > Linux Forums > Linux - Software > Linux - Kernel

All times are GMT -5. The time now is 10:48 PM.

Main Menu
Advertisement
My LQ
Write for LQ
LinuxQuestions.org is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
Syndicate
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration