Transcript Live CDs - CCCC Linux SIG

Live Distros
Instant OS Gratification on a disk
By
Carl Weisheit
PART ONE: What is a live CD?
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A “Live Distro” is an operating system that
will run from a CD, DVD, Floppy, or USB
drive without installation on a hard drive.
They access programs and files “on the fly”
from a compressed image on the disc.
You can save your work and computer
settings to a flash drive allowing you to take
your ‘customized system’ around with you.
Live Distros are available for the same uses as
“regular Distros”, they are just more portable.
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Amateur Radio
Astronomy
Bioinformatics
Clustering
Computer forensics
Desktop OS
Development
Diagnostics tools
Education
Firewall / router
Gaming
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Media production
Medical
Rescue disk
Robotics
Science
Security
Server
System Administration
Thin client
Windows antivirus
Live Distros can include the same
tools found on “regular” distros:
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Editors
Word processor
Spreadsheet
PDF tools
Calculators
Net browsers
Instant messaging
Media players
Cd burners
Floppy disk tools
Desktop Themes
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Games
Firewalls
Networking tools
Image tools
Paint programs
File managers
Partitioning tools
File Backup & recovery
System monitor
Hard drive installer
Terminal emulator
Live CDs auto-detect the hardware you are using,
however they are not infallible.
Boot Cheat Codes allow users to manually change
hardware settings.
Historic milestones in Live CDs
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1991-Linux project started by Linus Torvalds
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1993-Debian distro began by Ian Murdock
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1999-Duncan MacKinnon and Linuxcare gave out 10,000
bootable business cards at trade shows
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1999/2000-Knoppix distro created by Klaus Knopper, combines
Debian distro on live CD based on bootable business card
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Today there are over 300 live distros based on linux, unix,
solaris, and even XP. These distros support all major platforms
and cpu architectures.
How to get live CDs
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Search http://distrowatch.com for linux distros
Search http://www.frozentech.com for live distros
Search http://www.livedistro.org for live distros
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Above sites provide links to distro’s homepages
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Get additional info and help at distro’s homepage
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Download latest free CD / DVD images from distro
homepage via HTTP, FTP, or Bit torrent
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Sites also sell CDs if you don’t have internet
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PART TWO: UNDER THE HOOD
“The boot process”
Computer BIOS loads the
bootloader: isolinux.bin
Isolinux creates a ramdisc and loads
linux kernal and miniroot directory
A script file in the miniroot called linuxrc mounts
the compressed image, which holds the majority
of the user programs and sets up hardware
/etc/init takes over ,
further configures hardware
and starts the GUI
The UNIONFS seamlessly links writable files to the
read only files and directories on the CD. This allows
you to save configurations and data to a zip drive etc.
PART THREE: INSTALL METHODS
“Regular and frugal installs”
FULL INSTALLATIONS
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Most live distros have an icon or menu
selection to install the distro to a hard drive
while some like Knoppix require you to install
from the command line:
#> sudo knoppix-installer
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They then guide you through a series of
questions to partition the drives and install the
software just like regular distros.
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A hard drive install can speed up your OS
Frugal or poor mans install
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Using the boot cheat codes you can copy the compressed
image file to a folder on the hard drive or a USB drive.
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The distro will search for and run the image file when you boot
from a boot floppy, the USB drive, or the original Live CD.
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A further benefit is the compressed image file takes up less
space than a traditional install.
PART FOUR: RESCUE DISK
“Using a live CD to fix Windows and
other Linux installations”
CHANGING FORGOTTEN PASSWORDS
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In Linux
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In Windows
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Boot from live CD
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Edit the passwd or
shadow file to remove
your password
Try booting from
‘Austrumi’ or the ‘Petter
Hagen’ distro to remove
the password
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Reboot computer and
put in new password
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Reboot computer and
put in new password
Resizing or changing hard drive partitions
many tools such as GPARTED are available on live CDs
Hard drive tools to go
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Repair corrupted file system by using fsck
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Recover deleted files by using unrm and
lazarus
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Rescue files from damaged hard drives using
dd_rescue
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Back up and restore partitions using tar
use a live CD such as Knoppix
for virus scanning
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The live CD is read only media
The infected OS is not running
The live CD is a different OS entirely
The anti virus software is free
Use F-Prot or ClamAV
Be sure to connect to net and get latest
virus updates!
PART FIVE: REMASTERING
“Creating a custom Live Distro”
Remastering allows you to:
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Personalize the default settings
Choose a different window manager
Replace packages on disk with those
you like better
Install upgraded or later versions
Be creative
General steps in the
remaster process
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copy directories and configuration files to a folder on
hard drive
Chroot into folder and add or remove packages
and change settings
Create new CD image
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Use the mkisofs command to create the
compressed image file and final iso file to
burn to CD
THE END
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While I tried to remain true to most distros, Knoppix was
the basis for commands and filenames shown in
examples, other distros may vary.
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feedback and constructive criticism would be appreciated
on the general mail list to help us improve these
presentations
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Look for much more detailed, step by step, presentations
with live distros to come
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Discontinue use if itching or redness persist and see a
doctor