LPI Linux Certification/Kernel Components

Detailed ObjectiveEdit

Weight: 2

Description:
Candidates should be able to utilise kernel components that are necessary to specific hardware, hardware drivers, system resources and requirements. This objective includes implementing different types of kernel images, identifying stable and development kernels and patches, as well as using kernel modules.

  • Key knowledge area(s):
    • Kernel 2.6.x documentation
  • The following is a partial list of the used files, terms and utilities:
    • /usr/src/linux
    • /usr/src/linux/Documentation
    • zImage
    • bzImage


Kernel Image FormatsEdit

Two types of kernel image formats can be used on Intel platforms: zImage and bzImage. The difference between them is the way they bootstrap and how large the kernel can be, not the compression algorithm as one might think. Both use gzip for compression.

zImage

This is the old boot image format for Intel, which works on all known PC hardware. The bootstrap and the unpacked kernel are loaded into the good old, 8086-era 640 KB of low memory. The allowed kernel size is 520 KB. If your kernel excedes this size, you either have to switch to bzImage or put more of the kernel into modules. The boot image builder will tell you when this is the case.

bzImage

The b in this format stands for big. The bzImage kernel image is not restricted to 520 KB or even 640 KB. bzImage is now the preferred boot image. Though there are some reports of boot failures using this boot image type, these problems are being pursued because the kernel developers want the format to work on all Intel hardware.

Last modified on 8 February 2010, at 12:05