Updated: April 20, 2012
Multi-boot, such a lovely word. Reminds me of Lilo Dallas Multi Pass from The Fifth Element. But essentially, multi-booting is nothing special. I have a system with four operating systems installed side by side just on the internal disk and another four or five on an external device. I have several systems with two or three instances of Linux distros breezing happily. But having a live bootable multi-boot system is a different story altogether.
Why would you want something like that? Essentially, a single all-purpose distro ought to do it. And now that you've learned about live CD/DVD/USB persistence, then all seems to be well. But sometimes you may require multiple distributions and/or non-Linux operating systems to do whatever you need to do. Usually, this kind of need revolves around system administration and maintenance, forensics, rescue, backups, and similar tasks. All right, let me show you how this can be done.
We will begin with a Windows tool. YUMI is another useful Pendrivelinux.com tool, which lets you work with your distribution images and USB drives. In this particular case, YUMI stands for Your Universal Multiboot Installer. You can read more about its functionality on the website. Essentially, it works just like the regular USB Installer, except that you can place multiple items onto your drive. That was easy.
This is a powerful Linux tool that can create bootable multi-boot systems for you. The range of features and options is quite impressive, but rather than droning, let me gradually expose them.
To setup MultiSystem, you will need to download (direct link) the installation script, which will then configure everything for you, including installing additional required packages from the official repository, plus it will add its own. The website itself is in French, so you may want to grab the script above and start working with it. Some basic knowledge of the command line is required.
Let the script run. It will configure everything for you. Once it completes, you can access the utility from the system menu. Don't mind the spelling mistakes. I would recommend you log out and log back in to your session.
Now comes the interesting part. The first menu will ask you to select from an available list of USB devices, which must be formatted with FAT32, otherwise they will not be recognized in the list. Next, there's a big fat warning that GRUB2 bootloader will be installed to MBR. However, this does not mean your internal disk MBR will be overwritten, but the one on your selected USB drive. This can be a little alarming, so pay attention.
You can also choose the language and color scheme. The window itself is unresizable, which can lead to some crude aesthetics, but that's less important. Moreover, you can update or uninstall the tool from this first menu. Once you select the desired external device, you will be asked to answer and confirm two more prompts.
Again, there's some confusion. Earlier, the red warning informed us that the bootloader will be setup in the MBR, which reads /dev/sdc for our device. But here, it tells us that GRUB2 will be installed to /dev/sdc1, which is the first partition. Now, I have not explored too deeply, but there seems to be a syntax thingie here. Finally, you can enable icon in the gnome menus [sic], whatever that means. Seems innocent, so I clicked yes.
Finally, you will be taken to a very rich, very busy main window where you can setup your multi-boot system. This is where the real fun begins. In this first tab, which reads MS, you can configure your ISO images. You can drag & drop them into the rectangle at the bottom of the menu. Or you can click the blue icon and select multiple images. You can then shuffle the images or delete them. Best of all, MultiSystem lets you test your images in QEMU or VirtualBox, which it can also setup and install for you, if you choose. If you already have these virtualization solutions installed, then all is well.
Before we test, let me show you what other tabs contain. MultiSystem is an extremely versatile, powerful and complex tool. It is in fact a toolbox with dozens of helper utilities that can enhance your live experience. For example, under Menus, you can update the bootloader and change its settings, install BURG, perform a backup and restore of your configurations, add and resize persistence, download live CDs, and much more.
The Boot sub-menu lets you create a CD that will launch your USB, as well as add boot options for Windows XP/Vista and even Mac on Intel architecture. Again, you have the option to test your live USB. There's also an individual option to check a live CD before committing the image to the multi-boot setup.
The Non-Free sub-menu lets you setup various proprietary components. I am not really sure what they all are and what they mean, but it sees like a handful lot of useful things. All combined, MultiSystem is more than just a tool for burning ISO files to external media, it's a comprehensive suite for testing and setting up multi-boot systems.
Back to configuring multiple images. We have already added Puppy. Now, let's add another image, this time Ubuntu. Just drag and drop, type in your password and wait. The image will be mounted and copied to the external device.
Now we can test. If you click the VirtualBox icon in the main menu, it will fire up VirtualBox and setup the virtual machine automatically, so you do not need to worry about anything. Just lean back and enjoy. After a few moments, mostly depending on the speed of your USB device, the GRUB2 menu will come up with your selected images. And then, you get even more goodies, like Grub4Dos, Syslinux, Super Grub Disk, Super Grub2 Disk, memtest, and more. This is really awesome.
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Multi-booting live images is probably of secondary important to most people, however some of you will appreciate the ability to carry around five, six or maybe ten different distributions neatly packed onto a single USB drive. There could be many reasons, but primarily, you will perhaps need them for maintenance, system rescue or forensics, with emphasis on flexibility, versatility and social status.
If you ask me, this kind of setup could work for people who travel a lot, like to carry around useful portable tools and utilities with them, or need lean and mean, lightweight Linux distributions to aid them in their work, without having to lug around an installed laptop or alike. With those noble goals in mind, you have just learned about two handy tools that create such setups for you. YUMI is simple and straightforward. MultiSystem is a bit ugly, but it is powerful and versatile. Well, that would be all. Enjoy.