Installing two operating systems at the same time isn't just possible; it can also be downright slick. Whether you're a Mac user looking to occasionally use a given Windows application or someone looking for a risk-free way to try out different Linux versions, VirtualBox is the go-to freeware platform for virtualization. This program allows you to run any operating system in a contained, emulated environment.

What most people don't know, however, is that this same program allows you to seamlessly combine your native and guest operating systems, allowing you to work with windows from both systems side-by-side. Heck, you can even copy and past text between any two platforms. Combine OSX and Windows, or Windows and Ubuntu, or Ubuntu and Fedora: the possibilities are endless.

Installing Two Operating Systems With VirtualBox

If you've never used VirtualBox before, or any sort of virtualization software at all, some preliminary reading may be in order. If you want to create a virtual Windows environment, check out Jorge's article on installing Windows 7 on a virtual machine in Virtualbox. These instructions are quite specific to Windows 7, but can be easily applied to any version of Windows. Alternatively, you could make a VirtualBox-ready clone of your existing Windows operating system, courtesy of an article by Varun.

If testing various Linux distributions is more your thing, Jorge also has you covered: he wrote all about test driving Linux operating systems with VirtualBox. This is actually a great deal simpler than running Windows, as you can download pre-built packages.

Want a virtual OSX? I'm sorry to say that Apple's licensing forbids this, though if OSX is your native platform you can easily install VirtualBox to test other operating systems.

It's also possible, in theory, that some legally-questionable BitTorrent trackers have VirtualBox images you can use to boot OSX. But these are illegal, and VirtualBox's seamless mode won't work with these anyway. Don't check them out, and don't share links to them in the comments below.

Installing Guest Additions

So you've got your guest operating system of choice up and running, but notice that it's anything but seamless at this point? It's time to install the Guest Additions. These operating system tweaks make it possible to move your mouse from the guest OS to your native OS without missing a beat.

Installing these additions is simple: on the window of the VirtualBox instance containing you Guest OS click "Devices," followed by "Install Guest Additions." Then follow the on-screen instructions within your Guest OS to complete the installation.

installing two operating systems

For those running a guest Linux Operating System: if you downloaded a pre-built VirtualBox image, it's likely you already have the Guest Additions installed. If you suspect this isn't the case, however, the above method should work wonderfully for you as well.

Seamless Mode!

Now that you've got the Guest Additions up and running it's time for the real fun: trying out seamless mode. Click "Machine," then "Seamless Mode."

installing two operating systems

After you do this your host operating system and your virtual operating system should seem to combine. You'll have a taskbar from each and programs from each will be visible over your native operating system's desktop. If this hasn't worked, try pressing "Seamless Mode" again - this will usually do the trick.

installing two operating systems

As you can see above, this is a great way to play Ubuntu and Window's versions of solitaire at the same time. If you're looking for more practical ideas, however there are a few. Using Ubuntu's version of Firefox is a great way to ensure your native Windows system is completely secure. If you're a Linux user, seamless mode is a great way to use your Windows-only applications whilst still feeling at home within Ubuntu.

Any application supported by your guest OS can be installed on a virtual machine, provided you've allowed for enough hard drive space to support them all.

boot two independent operating systems

Conclusion

Seamless mode is a slick, underexplored feature of VirtualBox. It's fit into my workflow on a regular basis, and can work wonders for anyone who needs to run two systems at once for any reason.

What do you guys think? Is this a cool and useful feature, or merely a gimmick? Do you have any advice for using it and getting it all set up? Can you think of any specific use you'd have for this functionality? Let us know in the comments below!