Guide Linux+ to Linux Certification, Second Edition
Chapter 9 System Initialization and X Windows
Objectives
Summarize the major steps necessary to boot a Linux system Configure the LILO and GRUB boot loaders Dual boot Linux with the Windows OS using LILO, GRUB, and NTLOADER Understand how the init daemon initializes the system at boot time into different runlevels
Linux+ Guide to Linux Certification, 2e
2
Objectives (continued)
Configure the system to start daemons upon system startup Explain the purpose of the major Linux GUI components: X Windows, Window Manager, and desktop environment List common Window Managers and desktop environments used in Linux Configure X Windows settings using various Linux utilities
Linux+ Guide to Linux Certification, 2e 3
The Boot Process
POST: Series of tests run when computer is turned on
Ensures functionality of hardware
MBR: Defines partitions and boot loader
Normally located on first HDD sector
Boot loader: Program used to load an OS MBR might contain pointer to a partition containing a boot loader on the first sector Active partition: Partition pointed to by MBR
One per HDD
Linux+ Guide to Linux Certification, 2e 4
The Boot Process (continued)
/boot: Directory containing kernel and boot-related files Vmlinuz-<kernel version>: Linux kernel file Daemon: System process that performs useful tasks
e.g., printing, scheduling, OS maintenance
Init (initialize) daemon: First process started by Linux kernel
Loads all other daemons Brings system to usable state
Linux+ Guide to Linux Certification, 2e 5
The Boot Process (continued)
Figure 9-1: The boot process
Linux+ Guide to Linux Certification, 2e 6
Boot Loaders
Primary function: Load Linux kernel into memory Other functions:
Passing information to kernel Booting another OS
Two most common boot loaders:
Linux Loader (LILO) GRand Unified Boot loader (GRUB)
Linux+ Guide to Linux Certification, 2e
7
LILO
Traditional Linux boot loader Typically located on MBR Allows choice of OS to load at startup To configure, edit /etc/lilo.conf
Linux+ Guide to Linux Certification, 2e
8
LILO (continued)
append= keyword (in /etc/lilo.conf): Useful for manually passing information to Linux kernel
Can pass almost any hardware information
Format is hardware dependent
Must reinstall LILO if /etc/lilo.conf file altered lilo command: Reinstalls LILO
-u option: Uninstall LILO
Linux+ Guide to Linux Certification, 2e
9
GRUB
More recent than the LILO boot loader Stage 1: First major part of GRUB
Typically resides on MBR Points to Stage 1.5
Stage1.5: Loads filesystem support
Resides in /boot/grub
Stage2: Performs boot loader functions
Displays graphical boot loader screen
To configure, edit /boot/grub/grub.conf
Read directly by Stage 2 boot loader HDDs and partitions identified by numbers
Format: (hd<drive#>,<partition#>)
Linux+ Guide to Linux Certification, 2e 10
GRUB (continued)
Figure 9-3: GRUB boot loader screen
Linux+ Guide to Linux Certification, 2e 11
GRUB (continued)
GRUB root partition: Partition containing Stage 2 boot loader and grub.conf file GRUB normally allows manipulation of boot loader
To prevent, enable password protection
grub-md5-crypt command: Generates encrypted password for use in grub.conf file Can switch boot loader from GRUB to LILO at any time grub-install command: Installs GRUB boot loader
Linux+ Guide to Linux Certification, 2e 12
GRUB (continued)
Figure 9-4: Viewing help at the GRUB boot loader screen prompt
Linux+ Guide to Linux Certification, 2e 13
Dual Booting Linux
Only one OS may be used at a time Boot loader may be configured to allow choice of OS at boot time
Linux+ Guide to Linux Certification, 2e
14
Using LILO or GRUB to Dual Boot other Operating Systems
Dual boot: Two or more OSs exist on HDD Easiest if Linux installed after another OS
Allows installation program to detect other OS
Place appropriate entries in boot loader configuration file
LILO and GRUB cannot load Windows Kernel directly
Linux+ Guide to Linux Certification, 2e
15
Using LILO or GRUB to Dual Boot other Operating Systems (continued)
Figure 9-5: Partitioning for a dual boot system
Linux+ Guide to Linux Certification, 2e 16
Using LILO or GRUB to Dual Boot other Operating Systems (continued)
Figure 9-6: Configuring GRUB for a dual boot system
Linux+ Guide to Linux Certification, 2e 17
Using FIPS
Windows installers use entire HDD for Windows partitions
Leaves no space for Linux
First non-destructive Interactive Partition Splitter (FIPS): Resizes Windows partition
Preserves Windows OS on Windows partition Creates space to install Linux
Linux+ Guide to Linux Certification, 2e
18
Using FIPS (continued)
Guidelines/limitations to using FIPS:
FAT16 and FAT32 filesystems only Will only work with primary Windows partition Windows partition split into two primary partitions Need sufficient free space within existing Windows partition to allow Linux installation
Linux+ Guide to Linux Certification, 2e
19
Using a Windows Boot Loader to Dual Boot Linux
Specify location of GRUB or LILO in Windows boot loader configuration NTLOADER: Boot loader available with Windows NT/2000/XP
At boot time, prompts for OS to boot Able to load LILO or GRUB
Windows must be installed on first primary active partition
NTLOADER placed on MBR by default
Linux+ Guide to Linux Certification, 2e 20
Using a Windows Boot Loader to Dual Boot Linux (continued)
Figure 9-7: Configuring GRUB to reside on a Linux partition
Linux+ Guide to Linux Certification, 2e 21
Using a Windows Boot Loader to Dual Boot Linux (continued)
When Linux installed, install GRUB on first sector of the partition
Avoids overwriting NTLOADER in MBR
After Linux installed:
Run Linux rescue utility Make GRUB bootable image file (linboot.bin) Reboot into Windows OS Copy linboot.bin to C:\ Configure NTLOADER configuration file
Linux+ Guide to Linux Certification, 2e 22
Using a Windows Boot Loader to Dual Boot Linux (continued)
Boot.ini: File used to configure NTLOADER For NTLOADER to be able to boot Linux, must specify the path to linboot.bin
Linux+ Guide to Linux Certification, 2e
23
Using a Windows Boot Loader to Dual Boot Linux (continued)
Figure 9-8: NTLOADER operating system choice screen at boot time
Linux+ Guide to Linux Certification, 2e 24
Linux Initialization
Kernel assumes control after Linux loaded
Executes first daemon process (init daemon)
/etc/inittab: Configuration file for init daemon
Linux+ Guide to Linux Certification, 2e
25
Runlevels
Runlevel: Defines number and type of daemons loaded into memory and executed
init daemon responsible for changing runlevels
Often called initstates
runlevel command: Displays current and most recent runlevel init command: Change OS runlevel telinit command: Alias to init command
Linux+ Guide to Linux Certification, 2e
26
The /etc/inittab File
Consulted to start or stop daemons /etc/rc.d/rc.sysinit: First script executed during system startup
Init hardware, set variables, check filesystems, perform tasks system for daemon loading
mingetty program: Displays login prompt on character-based terminals /etc/rc.d/rc.local file: Performs post-system-startup tasks
Linux+ Guide to Linux Certification, 2e 27
The /etc/inittab File (continued)
/etc/rc.d/rc command: Executes all files starting with S or K in /etc/rc.d/rc*.d/
Runlevel must be specified
e.g., /etc/rc.d/rc 5 will execute files in /etc/rc.d/rc5.d/
Symbolic links to scripts that start daemons S means "Start," K means "Kill"
Linux+ Guide to Linux Certification, 2e
28
The /etc/inittab File (continued)
Figure 9-9: The Linux initialization process
Linux+ Guide to Linux Certification, 2e 29
Configuring Daemon Startup
Most symbolic links in /etc/rc.d/rc*.d point to daemon executable files in /etc/rc.d/init.d Most daemons accept arguments start, stop, restart To add daemons to be automatically started:
Add executable to /etc/rc.d/init.d Create appropriate links to /etc/rc.d/rc*.d
ntsysv utility: Modifies file entries in /etc/rc.d/rc*.d directories
Linux+ Guide to Linux Certification, 2e 30
Configuring Daemon Startup (continued)
Figure 9-10: Results of ntsysvlevel 5 command
Linux+ Guide to Linux Certification, 2e 31
The X Windows System: Linux GUI Components
Figure 9-11: Components of the Linux GUI
Linux+ Guide to Linux Certification, 2e 32
X Windows
X Windows: Core component of Linux GUI X client: Requests graphics from X server and displays them
Does not need to run on same computer as X Windows
X server: Draws graphics XFree86: OSS version of X Windows
Originally intended for Intelx86 platform
Linux+ Guide to Linux Certification, 2e
33
Windows Managers and Desktop Environments
Window manager: Modifies look and feel of X Windows Desktop environment: Works with a window manager to provide standard GUI environment
Uses standard programs and development tools KDE and GNOME are most common
Linux+ Guide to Linux Certification, 2e
34
Windows Managers and Desktop Environments (continued)
K Windows Manager (kwm): Window manager that works under KDE Qt toolkit: Software toolkit used with KDE GNOME Desktop Environment: Default desktop environment in Red Hat Linux
Sawfish Window Manager GTK+ toolkit
Xfce Desktop Environment: Consumes less hardware resources than KDE or GNOME
Linux+ Guide to Linux Certification, 2e 35
Windows Managers and Desktop Environments (continued)
Figure 9-12: The KDE desktop
Linux+ Guide to Linux Certification, 2e 36
Windows Managers and Desktop Environments (continued)
Figure 9-13: The GNOME desktop
Linux+ Guide to Linux Certification, 2e 37
Windows Managers and Desktop Environments (continued)
Figure 9-14: The Xfce desktop
Linux+ Guide to Linux Certification, 2e 38
Windows Managers and Desktop Environments (continued)
Figure 9-15: The Tab Window Manager
Linux+ Guide to Linux Certification, 2e 39
Starting and Stopping X Windows
runlevel 5 starts gdm
Displays graphical login screen Allows user to choose the desktop environment or Window Manager
/etc/X11/gdm/gdm.conf: Contains gdm configuration data For runlevel 3:
Start gdm manually Or, use startx command
Linux+ Guide to Linux Certification, 2e 40
Starting and Stopping X Windows (continued)
Figure 9-16: The GNOME Display Manager
Linux+ Guide to Linux Certification, 2e 41
Starting and Stopping X Windows (continued)
startx command: start X Windows and Window Manager or desktop environment specified in .Xclients file in home directory
Usually points to .Xclients-default file
Edit .Xclients-defaults file to start other desktops or Window Managers on X Windows Desktop Switching Tool: Change settings used in the .Xclients-default file from KDE or GNOME
Linux+ Guide to Linux Certification, 2e
42
Starting and Stopping X Windows (continued)
Figure 9-17: The Desktop Switching Tool
Linux+ Guide to Linux Certification, 2e 43
Configuring X Windows
X Windows interfaces with video hardware
Requires information regarding keyboard, mouse, monitor, and video adapter card
Required video adapter card information:
Model Amount of RAM Chipset
Required monitor information:
Maximum resolution supported Horizontal sync (hsync) range Vertical sync (vsync) range
Linux+ Guide to Linux Certification, 2...