System information

214 System Analysis and Tuning Guide
The first parameter represents the kernel image. The second parameter is the dump
file captured by kdump. You can find this file under /var/crash by default.
18.7.1 Kernel Binary Formats
The Linux kernel comes in Executable and Linkable Format (ELF). This file is usual-
ly called vmlinux and is directly generated in the compilation process. Not all boot
loaders, especially on x86 (i386 and x86_64) architecture, support ELF binaries. The
following solutions exist on different architectures supported by SUSE® Linux Enter-
prise Server.
18.7.1.1 x86 (i386 and x86_64)
Mostly for historic reasons, the Linux kernel consists of two parts: the Linux kernel it-
self (vmlinux) and the setup code run by the boot loader.
These two parts are linked together in a file called bzImage, which can be found in
the kernel source tree. The file is now called vmlinuz (note z vs. x) in the kernel
package.
The ELF image is never directly used on x86. Therefore, the main kernel package
contains the vmlinux file in compressed form called vmlinux.gz.
To sum it up, an x86 SUSE kernel package has two kernel files:
• vmlinuz which is executed by the boot loader.
• vmlinux.gz, the compressed ELF image that is required by crash and GDB.
18.7.1.2 IA64
The elilo boot loader, which boots the Linux kernel on the IA64 architecture, sup-
ports loading ELF images (even compressed ones) out of the box. The IA64 kernel
package contains only one file called vmlinuz. It is a compressed ELF image. vm
linuz on IA64 is the same as vmlinux.gz on x86.
18.7.1.3 PPC and PPC64
The yaboot boot loader on PPC also supports loading ELF images, but not com-
pressed ones. In the PPC kernel package, there is an ELF Linux kernel file vmlin
ux. Considering crash, this is the easiest architecture.