Two-Minute Drill


Here are some of the key points from the certification objectives in Chapter 3.

The BIOS Initialization Sequence

  

While not strictly a part of the exam, it's important to know the basics of the BIOS.

  

You can change the boot sequence from the BIOS menu.

  

Once the BIOS detects your drives, it hands control to GRUB via the master boot record (MBR).

The GRUB Boot Loader

  

GRUB, the GRand Unified Boot loader, is the default for RHEL 5.

  

Errors in the GRUB configuration file can lead to a number of boot problems, including kernel panics.

  

You can read the GRUB configuration file from the GRUB command line.

Kernel Initialization and the First Process

  

You can analyze how the kernel booted your system through /var/log/dmesg.

  

As the kernel initializes your system, it loads important modules such as the ext3 filesystem.

The First Process and /etc/inittab

  

Once the kernel boots, it hands control to init, also known as the First Process.

  

The init process starts your system as configured in /etc/inittab.

  

One of the key configuration files started by the First Process is /etc/rc.sysinit.

Runlevels

  

There are six different runlevels available; the default is configured in /etc/ inittab.

  

Don't configure a default runlevel of 0 or 6.

  

The default runlevel configured in /etc/inittab starts scripts in the associated /etc/rcx.d directory, where x is the runlevel.

  

You can boot to the runlevel of your choice from the GRUB configuration menu.

  

Study the /etc/rc.d hierarchy and the /etc/inittab and /etc/rc.d/rc.sysinit files. This is the key to understanding what's happening during the boot process.

Controlling Services

  

The chkconfig command gives you a simple way to maintain the /etc/rc.d directory structure.

  

The ntsysv and system-config-services commands provide console and GUI tools for the same purpose.

System Configuration Files

  

There are a number of non-network configuration files in the /etc/sysconfig directory.

  

You can edit many of these files directly or use GUI tools, which you can start with commands such as system-config-date, system-config-keyboard, and system-config-services.



RHCE Red Hat Certified Engineer Linux Study Guide (Exam RH302)
Linux Patch Management: Keeping Linux Systems Up To Date
ISBN: 0132366754
EAN: 2147483647
Year: 2004
Pages: 227
Authors: Michael Jang

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