GUI Tab: Preparing the Medium

This tab presents the various possibilities for installing the live system that was built on the 'larchify' tab onto a bootable device, which can be in iso9660 form (to burn to a CD/DVD), or a partition on a hard disk or flash storage device. A suitable bootloader can also be installed. In addition the copying of a larch system from one medium to another is supported and also the building of a boot-iso for a USB device.

Bootloader

To keep things simple only the syslinux family of bootloaders is supported. This allows booting from CD/DVD (isolinux) and partitions formatted with 'ext2/3/4' or 'btrfs' (extlinux) or with 'vfat' (syslinux).

Boot entries/options

The bootloader offers a selection of 'boot lines', so that different systems, or various kernels in combination with various boot options can be started. The file 'cd-root/boot/bootlines' in the profile contains this information for the larch live system in a form which can be converted automatically into bootloader specific formats. This allows the boot menu entries to be supplied in the profile in an easily parseable way which is independent of the actual bootloader which is used in the end. The format should be pretty clear from the default version.

The 'bootlines' file covers only the menu entries for the larch live system. All other entries must be supplied in a bootloader specific 'template' file. A button is supplied to edit this, too. Note the '###LARCH' line, which specifies where the information from the 'bootlines' file is to be included.

The 'cd-root' directory

The handling of this directory is described here. It allows customisation of files on the medium which are not directly used by larch, but can be useful in certain circumstances. You could, for example, include a package repository, or just about any data files needed by the specific live system. The default settings might well be adequate for many purposes. There is a button to open a file browser on this directory (within the current profile). Note that only the '/boot' and '/larch' directories of the medium are available for customisation, so in general any application data should be placed in the '/larch' directory.

Choice of build medium

The main choice is between a partition (on a hard-disk, USB-stick, etc.) and an iso file (for writing to a CD/DVD). It is also possible to build a 'boot-iso' (to burn to a CD) for an already prepared larch USB-medium, to enable booting on older systems which don't support booting from USB.

The destination can be changed by clicking the button - a menu appropriate to the type of destination appears (note that for destination partitions only unmounted ones will be shown).

Build an iso, for CD or DVD

Only limited customisation possibilities are offered here, you can set the volume label ('-V' option to mkisofs). The boot CD is discovered at boot by searching for '/larch/system.sqf'.

Install to partitition

Here one must select the partition to install to - which must be plugged in and not mounted (good luck to automounters!), and also select how the live initramfs is to find the correct partition. The available options are:

  • Partition: The device will be sought on the basis of its (current) device name - such as /dev/sdb1. This is only suitable if you can be sure the device will always get the same name (which - especially with pluggable devices - is unlikely).
  • UUID: Each device normally has a unique UUID, so this is a pretty reliable method. It's just that the UUIDs themselves are rather ungainly and unmemorable.
  • LABEL: Booting on the basis of the device label can be quite reliable and quite readable, so it might be a good compromise. This is the recommended choice.
  • Search (for larchboot): The live initramfs tests all visible devices until it finds one containing the file larch/larchboot.

The partition will be formatted with 'ext4', and you can choose whether to use the journalling feature of this file-system. No other file-system types are supported at present (though by formatting exernally and using the 'Don't format' option it is possible to use another one, so long as it is supported by syslinux/extlinux). The option to install without formatting should only be used by people who know what they are doing, in general it is not recommended. Another option for experts is the suppression of the installation of the bootloader to the Master Boot Record of the live medium. If you don't install to the MBR, you will need to provide some other means of booting the device, but in certain circumstances this could be a useful option.

The option 'Not bootable via search' suppresses the generation of the 'larch/larchboot' file, so that the method of medium detection which searches for this file will not work on the generated medium (this of course makes no sense if the 'Search (for larchboot)' medium detection method is selected for this medium).

Create boot iso

In this case the source medium - a partition containing the larch system (presumably on a USB device) must be selected, by clicking on the button in the source frame. Only unmounted partitions with volume labels will be offered. A small iso file with just the kernel and initramfs, plus the necessary bootloader files, will be created. This is to cover cases where a machine cannot boot from USB devices, but can boot from a CD. Note that the USB device for which the CD is to be generated must be plugged in, but not mounted.

Volume label

The maximum length of the label should be 16 characters, which is ok for both 'iso' (CD/DVD) and for 'ext4'.

Write the larch medium

When enough information is available, this button will be enabled and the generation can be started.

Copying larch media

By choosing a medium (iso-file or labelled partition) in the source frame, it is possible to copy this system to another medium. Certain aspects of the destination device can be set just as in the initial creation process. When a device or iso-file is selected as source a simple validity check will be performed on it, a failure resulting in the selection not being accepted.

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