[linuxkernelnewbies] Linux Live for CD & USB

[peter teoh]

http://www.linux-live.org/?howtos Linux Live is a set of shell scripts which allows you to create your own Live Linux from an already installed Linux distribution. The Live system you create will be bootable from CD-ROM or a disk device, for example USB Flash Drive, USB Pen Drive, Camera connected to USB port, and so on. People use Linux Live scripts to boot Linux from iPod as well.   How to build a Live distro: 1) Install your favourite distro to disk partition, or into a folder on your existing system.     Slackware is recommended but not required. 2) Build aufs kernel module and squashfs kernel module (optionally patched to support LZMA)     The step above is not required if you use precompiled Linux Kernel from this website     Install kernel modules to the newly installed distro to /lib/modules/`uname -r`/fs/.     Make sure you are running the same kernel you used to compile modules 3) Remove all unnecessary files (for example man pages and all other files you don't need),     to make your Live Linux system as small as possible (this step is optional). 4) Download Linux Live scripts from this website and unpack it in /tmp     Read ./DOC/requirements.txt to find out what linux-live scripts need     Edit .config file if you need to modify some variables 5) Finally login as root and run ./build     Live distribution's 'directory tree' will be created in /tmp/live_data_1234     where 1234 is a random number 6) To make ISO image, run make_iso.sh     To make a bootable (usb) disk, run bootinst.sh   Working example If you're just looking for a working Linux Live system, visit www.slax.org   Interesting features of Linux Live scripts 1) persistent changes Use 'changes=...' boot parameter to specify persistent changes directory or file. If a directory is used, eg. changes=/some_dir/ and the /some_dir/ is found on some partition on your disk, then all the changes made to the root filesystem will be saved to that directory. This works even if /some_dir/ is on NTFS or VFAT, thanks to posixovl overlay (an userspace filesystem, already included). Important note: if you plan to save changes on VFAT, make sure to modify your distribution's shutdown scripts. It must not execute killall, else posixovl is killed and everything is wrong. Instead, call the cleanup script from /mnt/live/cleanup. If a file is specified for the changes boot parameter, eg. changes=/path/file.dat, and the file has a valid filesystem inside, then the file will be loop-mounted and changes written to it. You may also use changes=/dev/sda1/path/ and changes=/dev/sda1/path/file.dat ... to specify particular device where to look for. Other devices will be skipped (will not be even mounted). 2) adding modules on the fly In the ./tools/ directory of Linux Live, you will find 'activate' and 'deactivate' scripts. You may use these two to add and remove additional LZM modules to the root filesystem on the fly, while your Live OS is running. 3) installable system to disk As mentioned in the previous section, there exists a script called bootinst.sh (and bootinst.bat) to setup a boot sector to boot Live Linux from disk. If you combine that with persistent changes, your Live distro will behave like INSTALLED, all changes are transparently stored to the boot media (even to USB), and you can still use 'activate' and 'deactivate' commands to manipulate the root filesystem. 1) Download Linux Live scripts FTP link released linux live 6.3.0 8th of September 2009 history... older   2) Download precompiled kernel with aufs and squashfs modules     (if you are lazy to build kernel and modules yourself) link released linux kernel 2.6.27.27 26th of November 2008 history... older   You may want to build your own kernel from sources (most people don't need this) aufs source squashfs source lzma squashfs patch I prepared build-scripts with sources for you here, so just download all the files and directories from there. Feel free to replace my config by your own kernel configuration and run ./build.kernel script. It will make a 2.6.27.27 kernel for you. Linux Live scripts version 6 are the most innovative scripts available. AuFS provides better stability compared to old unionfs, squashfs with LZMA support provides great compression ratio and amazing decompression speed. What's new compared to old Linux Live scripts v 5? - aufs is used instead of unionfs, brings great stability and features - squashfs is patched with LZMA compression, so compressed filesystems are up to 30% smaller - no need to patch your distro's startup scripts in order to remove remount of root rw - no need for udev as the devices are created during live startup - CD tree is simplified, you may call your distro as you like, eg. slax, knoppix, etc. - support for booting from USB and PCMCIA/CardBus device - support for writing persistent changes even to VFAT (thanks to posixovl) - added a script to create bootable disk (including USB) in Linux and Windows Read raw changelog for more detailed info   (c) 2009 Tomas M. (www.slax.org) - I will be happy for all feedback, mail me!