When you install Windows on a VirtualBox virtual PC, VirtualBox creates a file that defines your virtual PC, its files, Windows installation and all. Technically, but not legally, you could give that VirtualBox file to someone else who would be able to run Windows in their VirtualBox without first having to carry out the Windows installation.
Run Linux in Windows using virtualisation
Some free operating systems, mostly Linux variants, are distributed this way. We’re going to use one of those to see how easy this approach makes it to try out (or even use for real) Linux within VirtualBox. Here, we're using Damn Small Linux (DSL) which, as the name suggests, is a cut down version for quick downloads.
See also: Install Windows 8 on a Virtual PC using VirtualBox.
How to install Damn Small Linux using Oracle VirtualBox
1. Go to http://virtualboxes.org/images/damn-small/ where you’ll find VirtualBox virtual machines for several versions of DSL. Download the latest version which is a Zip archive and extract the files it contains. You’ll get two folders called Machines and VDI, the latter of which contains the virtual machine file.
2. Start up VM VirtualBox and on the main window click on the Create icon, just as you did to create the Windows 8 virtual machine. Enter ‘DSL’ as the name of your new virtual machine and you’ll notice that Type and Version update accordingly. Click on Next.
3. In the next dialogue box you’ll be asked how much memory to allocate to the virtual machine and you should accept the default by just clicking on Next.
4. Next you’ll be given several options regarding the virtual hard disk. Select ‘Use an existing virtual hard drive’, click on the folder icon to its right, select the VDI file that you downloaded from the Web, click on Open and then, back at the ‘Create Virtual Machine’ dialogue box, click on Create.
5. Your virtual machine will now be created and this will be reflected by the fact that the name of ‘DSL’ appears at the left hand part of the VM VirtualBox main windows and details are shown to the right. You’ll notice that that the DSL virtual machine is shown as Powered Off so start it up by clicking on the Start icon.
6. A second window appears – this is the screen of your virtual machine. If various error and information boxes appear just accept them. DSL will start and you’ll be asked to login. Do so using the username ‘dsl’ and the password ‘reverse’.
7. Once logged in the DSL main screen will appear just as if you’d installed DSL on your PC’s hard disk instead of Windows. You can explore the OS while, at the same time, experiencing the wonders of virtualisation which has made this possible. When you’re done, just select Close from VM VirtualBox’s Machine menu to shut down the virtual machine just like a real machine running DSL. All your settings and files will be saved for next time you start up this virtual machine.