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larch – a do-it-yourself live Arch Linux CD



Running a larch live-CD/USB system

Of course the details depend on what you have installed and how you have configured it. For example, the 'mini2' example profile builds a console-only system, the 'xmaxi' profile boots to xfce4.

One thing worth noting is that these supplied profiles automatically login to the root account, which - potentially - allows all sorts of 'dangerous' actions, like reformatting your disks or making a mess of your file-systems in other ways. This is because one of the main raisons d'ĂȘtre for larch is its use as an Arch-installation-and-rescue medium. For this, you need root access. However, if you want to use the system in other ways, e.g. for text or image editing, or for internet browsing or e-mail writing, it might be safer to do this as an unprivileged user. Such a user is easily created with the 'adduser' command, or in KDE with 'kuser' (or using the 'luser.py' script in the larch 'luser' package). If you have a writable boot medium, such changes can be 'remembered' by saving the session when you shut the system down (the possibility will normally be offered automatically).

Boot parameters

As the larch build system is highly configurable, the available boot parameters can also vary, but by default 'swap' and 'c2r' are provided. 'swap' indicates that an existing swap partition should be used (the default is not to use it). 'c2r' means 'copy to RAM', i.e. the system data is copied to main memory before the system is initialized. This allow the system to run very fast and frees up the boot device (e.g. the boot CD can be ejected and the drive used for another CD), but it does require a lot of memory (significantly more than the size of the boot medium), and the boot process is rather slow because so much data must be copied. Because of the high memory usage, I have arranged it so that 'c2r' also implies 'swap'. With A USB-stick as boot medium, the 'c2r' parameter should generally not really be needed, performance is normally pretty good and it doesn't occupy the CD-drive (if an extra boot CD is needed, on a machine that can't boot directly from USB, that can be removed after booting even without 'c2r').

Configuration

The supplied profiles are just intended as starting points for your own configurations, they are fairly primitive, in fact only a little more than a newly installed Arch sytem. If you are running a profile with X11, you may find that you need to configure it before it will run. Since Xorg version 7.3, it is often possible to run without an /etc/X11/xorg.conf, but it may be necessary to create and tweak the configuration file for your system. You can try 'X -configure' or 'xorgconfig' to create a starting point which you can then tweak. Start X with startx.

The 'xmini' and 'xmaxi' profiles use a slightly more elaborate login approach on the first terminal, with a simple menu as well as automatic login. There is also a logout gui for xfce, which together with the login script can trigger session saving directly, bypassing the console prompt.

If you are stuck with the console, there is still hope. It's not as pretty or newbie friendly as an X11 desktop, but still quite capable. I always like to have mc available, it's a real godsend for non-geeks (you should also install lynx so that HTML files can be displayed on the console - at a pinch you can also surf with it, but it is painful).

If your console keyboard map is wrong, try running km (I stole this from the standard Arch install CD and modified it a bit to work in larch). It also modifies '/etc/rc.conf', so the change can be retained for subsequent runs by performing a 'session-save'.

If you have a DHCP server on your network, you might well find that the network interface is configured automatically (assuming your rc.conf is configured appropriately). On my prototype, I could just fire up konqueror and the world was my oyster, as they say. If not, well I'm afraid it's not so easy. Until someone comes up with something better, you'll have to edit the appropriate configuration files (primarily '/etc/rc.conf') - see the Arch Linux documentation for details - and then do '/etc/rc.d/network start'. If you already have a running network interface but want to change it, you may need to stop it running first, using 'stop' instead of 'start', then make the changes, then start it. I don't know if 'restart' would work (it stops then starts the network) after a change to the configuration.

Of course the exact details of what you can do depends on what software you installed, so I won't rabbit on endlessly about it here. Nearly all configuration details should be just the same as in a normal, hard-disk based installation.

Installation to hard disk

The larch hard-disk installer larchin may be used to install Arch Linux to hard disk (or similar). At the moment it is very fresh and rather minimal, probably rather buggy, but I hope it will improve over time. It is not intended as a complete solution for all aspects of Arch installation, but I have tried to concentrate on those areas that are unique to the installation process. In other words it does very little system configuration, because such requirements can also exist in an already installed system, so I think this should be covered by separate tools. larchin deals with partitioning and formatting of hard drives, placing Arch Linux (primarily a copy of the live system on which it is running) on the newly formatted partitions, and installation of the GRUB bootloader. It is so fresh that it hasn't yet got any documentation yet, but it's usage should be very straightforward - just run 'larchin.py', as root).

As mentioned above the main approach to Arch installation covered by larchin is to copy the contents of the live system to a hard drive. Those (few) bits peculiar to the needs of a live system are removed and the result is a completely normal Arch Linux installation. I should perhaps mention the file 'larch0' in the '/.livesys' directory (copied there from the 'larch/copy' directory on the boot medium). This script is run at the end of the installation (if it exists) and allows custom installation actions to be performed. The possibility of doing a completely fresh installation using ftp to fetch the latest packages may be added at some point, but that is not yet certain.

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