Question about the vmlinuz file

Question about the vmlinuz file

[Alvaro Aguilera]

Hello,

perhaps someone here has a couple of minutes to explain me the
difference between these two vmlinuz files from different
distributions:

$file /boot/vmlinuz
/boot/vmlinuz-2.6.37-40-desktop: Linux/x86 Kernel, Setup Version
0x20a, bzImage, Version 2.6.37, Version 2.6.37-40, RO-rootFS, root_dev
0x301, swap_dev 0x4, Normal VGA

$file /boot/vmlinuz
vmlinuz: ELF 64-bit LSB shared object, AMD x86-64, version 1, stripped

the second file seems to be in ELF format and I cannot use it with my
cluster management software.

Is there a parameter I can use to compile the kernel image in one
format or the other? or a tool to convert them?

I couldn't find any hint on Google, nor I really know what exactly to look for.

Thanks for any help.
Alvaro.

Re: Question about the vmlinuz file

[Stratos Psomadakis]

On 02/26/2011 02:25 PM, Alvaro Aguilera wrote:
> Hello,
>
> perhaps someone here has a couple of minutes to explain me the
> difference between these two vmlinuz files from different
> distributions:
>
> $file /boot/vmlinuz
> /boot/vmlinuz-2.6.37-40-desktop: Linux/x86 Kernel, Setup Version
> 0x20a, bzImage, Version 2.6.37, Version 2.6.37-40, RO-rootFS, root_dev
> 0x301, swap_dev 0x4, Normal VGA
>
> $file /boot/vmlinuz
> vmlinuz: ELF 64-bit LSB shared object, AMD x86-64, version 1, stripped
>
> the second file seems to be in ELF format and I cannot use it with my
> cluster management software.
>
> Is there a parameter I can use to compile the kernel image in one
> format or the other? or a tool to convert them?
>
> I couldn't find any hint on Google, nor I really know what exactly to look for.
>
> Thanks for any help.
> Alvaro.
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http://en.wikipedia.org/wiki/Vmlinux

You can find lots of info by googling vmlinux or bzImage.

Afaik, the first is a bzImage, ie a compressed and stripped down version
of the vmlinux executable(which is the second one).

-- 
Stratos Psomadakis
<psomas@ece.ntua.gr>

Re: Question about the vmlinuz file

[Steven Rostedt]

On Sat, Feb 26, 2011 at 01:25:24PM +0100, Alvaro Aguilera wrote:
> Hello,
> 
> perhaps someone here has a couple of minutes to explain me the
> difference between these two vmlinuz files from different
> distributions:

What distributions?

On my Fedora 12 laptop:

$ file /boot/vmlinuz-2.6.32.23-170.fc12.x86_64 
/boot/vmlinuz-2.6.32.23-170.fc12.x86_64: Linux kernel x86 boot executable bzImage, version 2.6.32.23-170.fc12.x86_64 (mock, RO-rootFS, root_dev 0x902, swap_dev 0x3, Normal VGA

On my debian box:

$ file /boot/vmlinuz-2.6.32-trunk-amd64 
/boot/vmlinuz-2.6.32-trunk-amd64: Linux kernel x86 boot executable bzImage, version 2.6.32-trunk-amd64 (unknown@Deb, RO-rootFS, swap_dev 0x2, Normal VGA

> 
> $file /boot/vmlinuz
> /boot/vmlinuz-2.6.37-40-desktop: Linux/x86 Kernel, Setup Version
> 0x20a, bzImage, Version 2.6.37, Version 2.6.37-40, RO-rootFS, root_dev
> 0x301, swap_dev 0x4, Normal VGA

This seems to match my two boxes.

> 
> $file /boot/vmlinuz
> vmlinuz: ELF 64-bit LSB shared object, AMD x86-64, version 1, stripped
> 
> the second file seems to be in ELF format and I cannot use it with my
> cluster management software.

What distro is it?

> 
> Is there a parameter I can use to compile the kernel image in one
> format or the other? or a tool to convert them?

When I build my own kernel on Debian I have:

$ file /boot/vmlinuz-2.6.37.1+ 
/boot/vmlinuz-2.6.37.1+: Linux kernel x86 boot executable bzImage, version 2.6.37.1+ (rostedt@gandalf) #23, RO-rootFS, root_dev 0x900, swap_dev 0x2, Normal VGA

Your second file looks more like a vmlinux than a vmlinuz file.

$ file vmlinux
vmlinux: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), statically linked, not stripped

-- Steve