Many Live systems serve specific purposes, such as rescuing data, launching web servers, and so on. It seems logical, then, to accommodate several systems side by side on a USB stick. Such a multiboot system would prepare you for any eventuality and, as a side effect, use the ample space on today's USB sticks in a meaningful way.

Setting up such a USB stick is the domain of MultiBootUSB [1] and MultiSystem [2]. Both of these tools not only copy the desired Live systems onto the stick, they also automatically set up a boot menu from which you can easily select one of the distributions. Although MultiBootUSB and MultiSystem solve the same task, they differ significantly with respect to operations, functionality, and individual quirks.

Before you can use MultiBootUSB and MultiSystem, you first need to download the desired Live systems as ISO images. Add up the size of all the ISO images and a safety margin of 100MB, and this is the amount of space you need on the USB flash drive.

Before starting, make sure the stick is plugged in and disconnect all other USB devices that are not required, so you don't inadvertently write to the wrong disk.

MultiBootUSB

When this issue went to press, the MultiBootUSB developers were working hard on the new version 7.0. Whereas its predecessor was created with the Gambas development environment (i.e., in Basic), MultiBootUSB 7.0 relies on Python and Qt. However, there was no source code for the beta versions, and it remained unclear whether the developer intended to supply the source code with the finished version. Because the finished MultiBootUSB 7.0 should be available by now, the following article is based on the beta2 version.

MultiBootUSB only installs selected distributions on the USB stick – according to the developers, you have a choice of about 150 distros, but they are not saying which ones. In practical terms, feel free to try your luck. It looks like the more exotic distributions are ruled out: For example, Multiboot refused to install the TheSSS [3] mini-server. This is particularly surprising because TheSSS is based on 4MLinux, which MultiBootUSB handles without complaint.

The tool cannot erase the USB stick, so you need to make sure before starting that the stick has a sufficiently large empty partition with a FAT32 filesystem, as is normally the case for newly purchased memory sticks.

Instant Gravy

MultiBootUSB 7.0 is available as a prebuilt program from SourceForge [4]. You can also download the .tar.gz for your system. For example, if you have a 64-bit system you need the archive with 64bit in its name. The other directories on the download page contain older MultiBootUSB versions.

Once you have extracted the archive, start the multibootusb program as root; on Ubuntu, for example, use:

sudo ./multibootusb

When called with a normal user account, the beta version crashed reproducibly. Additionally, MultiBootUSB requires the udisks service. On some distributions, such as openSUSE, you might need to install this with your package manager. In openSUSE, the package goes by the name udisks. Once started, the main window appears (Figure 1).

Figure 1: Here, MultiBootUSB has already installed three ISO images to the USB stick (Ubuntu, openSUSE, and 4MLinux).

Under the MultiBootUSB tab, set the USB stick in Step 1; then, press Browse ISO, select the first ISO image, and then press Create. If the tool reports a failed integrity check, the ISO image might be corrupted, or it has overly restrictive permissions. The latter can happen, for example, if the ISO image is located on a network drive.

Following the same procedure, successively add all the other ISO images. If you have selected the wrong distribution, simply click on the list and then select Uninstall Distro. That's all there is to it. Press Close to exit the program, and you can now boot directly from the USB stick.

MultiSystem

The homepage for MultiSystem only speaks French and gives the impression that the tool is commercial. In fact, however, it is available under the GNU GPLv3, and you can get it completely free on SourceForge [5], where you can download an ISO image of a Live CD that launches Ubuntu 12.04 with a working MultiSystem.

This Live system is also the easiest way to use the tool. MultiSystem itself consists of a set of shell scripts that are obviously tailored to Ubuntu. Although the developers also offer a source code archive on SourceForge, it dates back to 2012. Additionally, you would still need to modify all the scripts for your distribution. Taking the current Live system is thus the best solution.

For Ubuntu users, though, the developers have set up a repository for you. Listing 1 shows how to install MultiSystem in this way; then, you start the tool by calling multisystem.

Just like MultiBootUSB, MultiSystem officially only supports selected distributions. The list is pretty extensive, though, and contains many exotic distributions [6]. Again, TheSSS is not included.

Also, MultiSystem only sees the first partition on the USB stick. You should therefore make sure it has enough free space. Alternatively, you can format the entire stick with MultiSystem.

$ sudo apt-add-repository 'deb http://liveusb.info/multisystem/depot all main'
$ wget -q -O - http://liveusb.info/multisystem/depot/multisystem.asc | sudo apt-key add -
$ sudo apt-get update
$ sudo apt-get install multisystem
$ sudo usermod -a -G adm "$SUDO_USER"