bzImage inplace of vmlinux

Message

pfadt_mann · Post by **pfadt_mann** » Mon Mar 05, 2007 12:27 am

I have always seen the vmlinux kernel used to boot with. In the gentoo Quick Install guide it has you moving the bzImage to /boot/kernel but the vmlinux is not used.

"livecd linux # cp arch/i386/boot/bzImage /boot/kernel"

Can someone tell me what the difference is between the bzImage and the vmlinux kernels

pfadt

desultory · Post by **desultory** » Mon Mar 05, 2007 1:05 am

The difference is that bzImage is compressed whereas vmlinux is not. For more information consult: http://en.wikipedia.org/wiki/Vmlinux#bzImage.

Xootneg · Post by **Xootneg** » Mon Mar 05, 2007 8:02 am

Gentoo used to have the default kernel image named the same as the kernel name. Such as - "linux-2.6.18-gentoo-r1" .. Maybe they still do it that way?

It was located as /boot/linux-2.6.18-gentoo-r1 for example

Also, you probably already know, but when you do a "make install" right after compiling your kernel, it auto writes the file as "vmlinux" directly into /boot (/boot/vmlinux), along with System.map if memory serves..

--
Xootneg

wynn · Post by **wynn** » Mon Mar 05, 2007 11:21 am

"make install" is in the kernel, the only other "Gentoo" install, AFAIK, is genkernel with the install argument.

"make install" in the kernel source runs

Code: Select all

sh /usr/src/linux-2.6.19-gentoo-r5/arch/i386/boot/install.sh 2.6.19-gentoo-r5 arch/i386/boot/bzImage System.map "/boot"

Looking at arch/i386/boot/install.sh shows that, first of all, it looks for ~/bin/installkernel and /sbin/installkernel (see below): if one of them exists then it is called to do the installation with the arguments to install.sh.

If neither of them exists then it saves an existing kernel image and System.map in /boot by renaming them with ".old" appended, copies bzimage to /boot/vmlinuz and System.map to /boot/System.map and then runs /sbin/lilo if it exists and is executable.

genkernel, however, saves the kernel as /boot/kernel-genkernel-x86-2.6.19-gentoo-r5, System.map as System.map-genkernel-x86-2.6.19-gentoo-r5 and the "initrd" as initramfs-genkernel-x86-2.6.19-gentoo-r5

[Edit] There is also installkernel and its companion mkboot from sys-apps/debianutils

installkernel version zImage System.map [directory]

The new kernel is installed into {directory}/vmlinuz-{version}, a link is made from {directory}/vmlinuz to the new kernel, and the previously installed kernel is available as {directory}/vmlinuz.old.

installkernel calls mkboot -i to make the system bootable after the kernel is installed.

mkboot [-r rootpartition] [-i] [-d device] [kernel]

By default the bootdisk will use the kernel /vmlinuz and the current root partition. Use the -r option to specify a different partition, and provide the new kernel file directly to specify a different kernel.

If invoked with the -i option, it tries to make a Debian GNU/Linux system bootable after a new kernel was installed by
/sbin/installkernel. If GRUB is installed, it does nothing. If LILO is in use, it runs /sbin/lilo.