Introduction
These pages describe how to set-up your computer in order to dual-boot (or multi-boot) Ubuntu and another Operating System(s), such as Windows or even another install of Ubuntu.
Back Up Your Data
First, of course, backup your data files and settings to an external backup medium before attempting any kind of install (or any other hard-drive manipulation). Accidents do happen, especially if you have not taken reasonable precautions beforehand. External hard drives, USB flash drives, and multiple DVDs or CDs are useful as external backup media.
One of the reasons people find linux easier to work with is that ALL the data and settings of all the users on a system are all contained within one easy to find folder. With some other operating systems (notably Windows) there are often stray parts, such as photo-albums, that are scattered elsewhere within their folders (hint look in "Application Data" folders both inside and outside the users folders).
Have a Recovery Cd for the existing Operating System(s)
Many Operating Systems allow their recovery system to be on a different media such as Usb-stick or Dvd and some even have a recovery or repair system on their installer Cd.
For the Windows one see here. Most linux systems can be repaired from most linux systems and/or their recovery or installer systems are easy to download given a working system such as a LiveCd.
A very tiny linux distro often found useful if Ubuntu's download is too much for a system is sliTaz although many people find Trinity Rescue Kit, or SystemRescueCd quite useful for fixing more complex problems with Windows. Trinity is command-line only, which is why i prefer sliTaz for most simple tasks if Ubuntu is unavailable for some reason but i have never used SystemRescueCd yet. Visit the DistroWatch home-page for the top 100 list of most popular distros and notice that Ubuntu is top of the list.
Some Cases
Most operating systems automatically, during install, check for other currently existing operating systems. They then add the existing ones into a boot-menu along with the new one so that you can choose which OS to boot into. Windows does not but it is the exception.
It is really only Windows that ignores anything currently on your system and because of that it becomes a little more difficult to dual-boot with Windows, if Windows is installed last. There are a lot of guides on how to dual-boot with Windows on the internet because it is likely to be a person's first attempt at setting up a dual-boot system. It is also the most difficult.
If Windows is already installed or gets installed before Ubuntu then the automatic systems make it easy, just as it does with any other OS.
General Case
Usually you already have an existing OS which you use. As you go through the Ubuntu installer you reach a section called "Partitioning Section", this offers you a choice to install Ubuntu alongside your existing OS. This does all the work for you. When you reboot the machine you get to a menu with these choices
- Ubuntu
Ubuntu in recovery mode = housekeeping & handy fix-it tools
- Old OS 1
- Old OS 2 (if you are making a multi-boot rather than just a dual-boot)
- Memtest
- There might be other options
If you installed Ubuntu first and a different OS last then the menu will look something like this
- non-Windows other OS
- Ubuntu
- Memtest (usually)
- There might be other options
So, if Ubuntu is not installed last then the "recovery mode" is missed but can be edited into the list.
Windows
There is a more detailed guide about dual-booting with Windows. It gives advice about some fairly specific, unusual cases, more notes about preparation and some detail about more advanced layouts rather then the defaults.
Below are some notes of peculiar problems with Vista and some Win7 although these may have settled down by the time you read this. Most other Windows such as Xp, 2000, ME and 98 are all fine.
Windows First
When Windows is installed first it is very very much easier because the Ubuntu installer automatically sorts the boot-loader and boot-menu for you. You can use a much more complicated, more precise route, if you prefer but for a first attempt it is probably better to let the automatic system do all the work for you. Just follow the obvious section in the "Partitioning Section" of the Ubuntu installer.
Windows Last
If Windows was installed last then the Windows boot-loader gets used which gives no menu and just boots straight into Windows. We can fix that fairly easily.
Vista
Service Pack1 and earlier may need to be resized from inside Vista as it sometimes stops you from being able to boot into Vista at all otherwise. There is a guide on how to recover from this but i cannot find it right now.
Win7
Apparently Windows 7 installs 2 partitions on a standard install from their Cd. The first partition being a tiny "Recovery Partition". Apparently this makes it difficult for grub to boot up the system. Since we haven't seen many questions about this in the forums i am not certain this is really a problem but i will attempt to link to some guides from a google search (or something) later.
Mac
There are a lot of guides out there but i gather the whole Mac section is being re-written. Need to find which pages to add links to in here.
Xen Server
There is a guide but also this question might help. Note at the end it mentions using "chainloader"
External Links
Ubuntuguide -- Installing Ubuntu -- concise and up-to-date
Step-By-Step Screenshot Tutorial to set-up an Ubuntu + Vista dual-boot
How-To: Dual-Boot Ubuntu 6.06 (Dapper) Linux Desktop Along Side Windows XP
HowtoForge Guide: Partition Resizing using UNetbootin-PartedMagic