Difference between revisions of "Live CD"

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The Live CD is based on Knoppix which is based on Debian.

Structure

The Live CD contains multipurpose GNU/Linux software and special software for elphel cameras. The software is organized as debian packages. Our debian packages are presented on our SourceForge page in the Live-CD and Players sections.

The root file system of Knoppix is compressed and the cloop kernel module is needed to decompress it on-the-fly when it is necessary. The CD contains the compressed root file system, boot loader and flash tarballs for different models of our cameras.

If you already have a Debian or Knoppix system installed, you can add some of our debs to work with our cameras.

We recommend installing the following packages from our SourceForge page:
• elphel-pack has utilities to configure the network specifically for the cameras (for rtp stream receiving), search for cameras on the LAN, update flash, and a helper for Mozilla/Firefox to work with .sdp files.
• netcardconfig-knoppix elphel clone to configure network cards and to make a simple bridge from several cards.
• patched MPlayer to watch and to record the rtp stream from our cameras.

To install the selected package(s) you may use the following command:

# dpkg -i --force-overwrite <deb-file-name>

Our version of netcardconfig-knoppix is dependant on the iputils-arping package. You may install it with:

# apt-get install iputils-arping

Our other packages and applied patches contain common minor improvements and bug fixes for the base distro.

Usage

Boot and use

Currently we have a Live CD only for the i386 architecture.

The Boot CD allows you to use Linux with the necessary network settings and utilities for our cameras without any modification of data on your hard drive.

Insert our CD in the CD drive and let the computer boot from this CD. It is possible you may need to change some BIOS settings to do it.

You may simply wait until the system is ready.

First you will see the Knoppix boot menu. To continue the boot you can wait longer or simply press Enter. The most common intervention during the boot process is setting the screen resolution to match your monitor (details below - [[1]]):

knoppix screen=1600x1200

In most cases Knoppix starts succesfully and automatically detects the computer hardware.

Then network cards will next be configured. The config script may ask you whether to make a bridge if your computer has several network cards. Press Enter or wait longer for the default configuration.

Then it automatically searches for elphel cameras on your LAN and makes a static html page with links.

After the boot completes you will see the page with cameras.

Knoppix cheat codes (boot parameters)

Special parameters can be set at the boot prompt.

The first word must be a name of a boot variant.

knoppix

Default mode.

expert

Verbose interactive mode.

debug

Debug mode.

failsafe

Boot without hardware autodetection.

memtest

RAM test.

Some further parameters separated by spaces can follow in any order.

screen=1280x1024

Use this if you have a monitor resolution higher than 1024x768 pixels and autodetection does not work.

lang=XX

Specify the two-letter designation of your language.

See the file "KNOPPIX/knoppix-cheatcodes.txt" on the Live CD for more in-depth information. Or online - here

Installing to hard drive

Working with packages

Knoppix is based on Debian. So it uses the debian package system. To list the installed packages use:

dpkg -l [<shell-like-template>]

To install a new package from file:

dpkg -i <deb-filename>

To install from servers:

apt-get install <package-name>

To search available packages:

apt-cache search <word>

To remove a package:

dpkg -r <package-name>

To get a description of installed package:

dpkg -s <package-name>

When booting from CD/DVD you can install/remove packages, but all changes will be temporary until reboot. Due to use of unionfs with ramfs you may temporarily change any file in the compressed filesystem, but changes are stored in RAM.

You can get a package file from any installed package:

dpkg-repack <package-name>

And convert it to tar.gz format which is used in Slackware, and which is easy to install in any GNU/Linux system without a package manager:

alien -t <file-name.deb>

How to Make a New CD Image

Here we describe the usage of the Live CD maker which can be downloaded from our SourceForge page. The tar archive contains several shell scripts and directories with patches and files for the CD.

Debs

This directory contains packages to install on the new CD and files with a list of packages and file names to remove. The script recognizes deb, rpm, and compressed tar archives. Use of debs is preferred.

Files "00remove-debs" and "00remove-files" contain, respectively, a list of debian packages, and files to remove before installing and updating new packages. Files "zzremove-debs" and "zzremove-files" are used similarly only after installation of new packages.

When the result is a DVD remastering the script uses some filenames but with -DVD suffixes.

Patches

there are 4 types of objects:

• diff patches, to be applied as patches to the knoppix root;
• tar.bz2 archives, to be unpacked in the knoppix root file system;
• executable files which will run with knoppix root as the current directory;
• directories which are ignored by the script, and can contain data for the executables.

Before application the initrd image is unpacked to the knoppix root and repacked after. So patches can modify the content of initrd.

Diff patches will be tested before application: they will be tried with --dry-run and -p0 and p1 options.

Executables are first run with --dry-run, with this option the files will be checked but it will not modify files.

Files to Be Placed on CD

The directory "newcd" contains files which will be placed on the CD as is. Put here new flash tarballs and HTML files which can be accessed without booting from the CD.

Scripts

download-debs

livecd-make

Before running this script, packages and patches must be placed in the "debs" and "patches" directories, Additional files should be located in the "newcd" directory. The remastering process consists of 5 phases:

1. Mount the source disk or image and unpack the compressed root file system to a directory named "new". An image of init root file system (initrd) is unpacked to new/initrd
2. Remove packages and files listed in debs/00remove-*
3. Install packages from "debs" directory and from internet servers with apt-get and finally remove files and debs listed in debs/zzremove-*. Some packages must be installed and removed in the specified order, so the script can do it in 5 phases, and files with packages and lists of packages can be named with digital prefixes 00, 01, 02, 0 and without prefix.
4. Check and apply patches, install scripts and simple tar archives in the "patches" directory. Remove backup files.
5. Compress new root filesystem, initrd and make a new disk image.

All operations are logged to file "livecd-make.log"

Usage:

./livecd-make [-d] [no-refresh] [no-upate] [quick] [unpack|remove|update|patch]

• unpack - stop after unpacking source distro into ./new/
• remove - stop after removing packages
• update - stop after installing new packages
• patch - stop after patches and scripts
• pause - wait for CR after each phase
• quick - do not use best compression
• dvd - make dvd image - do not delete most packages and split root, quick is recommended
• no-update - do not remove & install packages
• no-refresh - do not remove old ./new/ & unpack
• -d - do not redirect stderr to logfile

This script needs root priveleges.

Other Files

Diagnostic

Road map

see LiveCD Release Notes