LPI Linux Certification in a Nutshell, 2nd Edition

Objective 1: Kernel Components

A quick look at the contents of a kernel source directory and you get a good idea of the various pieces required to make your kernel function. If that doesn't give you any ideas, a glance through the documentation available should satisfy your curiosity. As discussed in Chapter 13 for Exam 102, the Linux kernel manages all aspects of your computer, virtual memory, the device drivers, networking code, and so on. The kernel also runs applications, but in a separate space outside the kernel. Applications and services are executed in user space.

There are very large books out there covering the nitty-gritty details of the development of the Linux kernel, but these topics are outside of the scope of a sysadmin, thus are not covered in the LPI Level 2 Exams. Essentially what LPI is looking for is for you to understand the applications for various types of kernel images, demonstrate proficient use of the various branches of kernel development, and efficiently implement kernel patches.

Kernel Image Formats

Let's review a couple of fundamentals. 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 ...