Windows, OS X, Linux oh my! Run all three together using VirtualBox by Sun Microsystems


Skill level: Intermediate to advanced
Time: 5 minutes (not including download and installation time)

Want to run a second OS on your computer but don't want to go through the hassle of dual booting? What if you could theoretically run as many operating systems as you like on your machine, while still having access to your native desktop and files when you want them? This is the concept behind virtual machines.

A virtual machine is like a "ghost image" of an operating system that is run through a virtual machine manager. Using a virtual machine manager, one can install almost any OS that they desire onto their system and run it side-by-side with their native applications. Because the virtual machine's entire entity is stored on a disk image, there is no need to worry about corrupting your native system.

Three of the most popular virtual machine mangers an the market are VMware, Parallels Desktop, and Sun Microsystems VirtualBox. Parallels and VMware both retail for $79.99 while VirtualBox is a free download. If you want to get your second-favorite OS up and running in as little time as possible, then it's obvious which of the three you should pick.

This how-to will focus on installing Windows 7 64-bit using Sun Microsystems VirtualBox. The path is relatively smooth, but there are a few pitfalls that must be avoided along the way. If you think you have what it takes, please step forward!

The Preliminaries

If you haven't installed VirtualBox on your computer already, head to and get the latest release. VirtualBox is available for Windows, Mac, Linux, and Solaris hosts.

During the download, locate an installation disk or ISO for your guest OS. You'll need them to do the initial boot.

Once VirtualBox is installed, continue to the next step.


Configure The Virtual Machine

Open VirtualBox and click "New" in the top menu pane. You will be prompted to fill out a registration form for a Sun Microsystems account. Once that's settled, name your virtual machine and specify the type of guest OS.


On the next page, select the amount of RAM that will be allocated to the virtual machine. It is recommended that you use at least 1GB = 1024MB for a Windows 7 installation. Note that the amount of memory your virtual machine uses is not dynamic. If you allocate 1GB of memory, then your virtual machine will be using 1GB of memory at all times. To prevent your native system from slowing to a complete crawl, VirtualBox limits the maximum amount of RAM you can select. Since I have 2GB of RAM on my laptop, VirtualBox capped off the memory usage of the guest OS to 1536 MB.

Now you will create the virtual disk image. This is where the guest will be installed and where all of its data will be stored. You have two choices when creating the image: fixed storage and dynamically expanding. Selecting fixed storage creates a disk image that is exactly as large as you specify from the very beginning, like a partition. Selecting dynamically expanding storage creates an empty image that can be filled with data over time. It is also much faster to create.

After choosing where you want the virtual disk image saved, it will be created with the file extension .vdi

VirtualBox will give you a quick summary of your virtual machine's stats. Click finish to advance to the main event.


OS Installation

Time for the first boot! You have two options:

Use guest OS installation disk:

Insert your guest OS installation disk and click "Start" in the VirtualBox menu pane. The First Run Wizard should start. Select "CD/DVD-ROM Device" and click next. If the First Run Wizard doesn't start, use the instructions below to manually navigate to your installation disk.


Use ISO:

Click "Start" in the VirtualBox menu pane. Once you see the blue intro screen, hit F12 immediately to select the boot device. When you see the black screen, move to the device menu as shown in the screenshot and select "More CD/DVD Images." This queues up the Media Manager. Click "Add" and navigate to the ISO (I happened to have the latest Linux release lying around). If the ISO is grayed out, it's probably corrupt.

Once your ISO is checked, go back to the black screen and select "Continue Booting." You should be greeted with a familiar start-up screen. This is the light at the end of the tunnel.

Follow the instructions on the install wizard as usual. At this point you should notice that your guest OS is using up all of the RAM that was allocated earlier. When asked where you want to install the guest OS, you should see the .vdi image that was created a few steps ago.

The installation will begin. The virtual machine may restart a couple of times. If you are supervising the installation when this happens DO NOT "hit any key" to boot from the CD/DVD drive. This will cause you to lose the current progress of the installation.

If all goes well, you hard work will be rewarded by the appearance of the desktop. Congratulations!


Using Your Virtual Machine

Now how do you get out of your guest OS to return to comforting reality? Just treat your virtual machine like a real computer. If you're running windows, head over to the start menu and click "Shut Down." It's that easy.

When you come back the next day after you have removed your installation disk or deleted your ISO, you might be frightened by a message stating that the device originally used to boot the virtual machine is no longer available. Disregard this message and click "Start." There is no need to worry since your virtual machine is safely installed on the .vdi image. Only if that were to disappear would you be in trouble.


VirtualBox is a fantastic piece of freeware that gets the job done despite the absence of a price tag. As proven in this how-to, it has the potential to run the latest and greatest operating systems. Keep in mind that you still get what you pay for. VMware and Parallels both offer a host of useful features as well as a much easier installation process.

Enjoy your new virtual world!

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