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Testing another operating system in a virtual machine such as VirtualBox is a great way to do so without having to wipe out your currently installed one. But just installing an operating system to the virtual machine isn’t enough – you need to install VirtualBox’s Guest Additions to get the best experience possible.
What exactly do the Guest Additions do, and how can you install them?
What Are The Guest Additions?
The Guest Additions are some extra bits of software that you install in the operating system you’re virtualizing. That operating system is also called the “guest OS”. Meanwhile, the operating system you actually have installed on your hardware and that you boot into every time you turn the system on is called the “host OS”. This is where the name Guest Additions comes from – they’re additions to the guest OS.
Installing the Guest Additions enables various extra features that are already built into VirtualBox. These include automatic resizing, seamless mode, the bidirectional clipboard, drag and drop, and generally better performance.
Automatic resizing allows you to resize the window of the virtual machine, and the desktop will automatically respond to completely fill in the new window size. The Guest Additions makes this happen by checking how big the window is, and then telling the guest OS those exact dimensions as if it’s the size of the monitor that is connected.
Otherwise, without the Guest Additions, the guest OS will tend to only do a 640×480, 800×600, or 1024×768 resolution and will remain that way no matter the size of the window of the virtual machine.
The Guest Additions also allow the clipboards to be shared, in either a one-directional or bidirectional way. I personally find bidirectional to be the most convenient, because then you can move between both operating systems without having to think twice. Anything you copy in one operating system (whether text, an image, or more) can be pasted in the other.
Drag and Drop
Another feature to aid in interoperability between the two operating systems is drag and drop. With this, you can simply drag items from one operating system to the other with ease, so you won’t have to mess around too much if you need something in the guest OS that’s stored on the host OS or vice versa.
Seamless Mode is a feature of VirtualBox that allows the desktops of the guest OS and host OS to merge. In other words, it allows applications that run on the guest OS to appear as if they are running natively on the host OS (although it will keep the window decorations of the guest OS rather than the host OS).
Additionally, with the shared clipboard and drag and drop features, working with both the guest OS and host OS at the same time is simple.
Finally, the Guest Additions also improve performance of the guest OS. For example, when you run Ubuntu in VirtualBox without the Guest Additions, it can act unnecessarily sluggish which gets annoying very quickly.
With the Guest Additions, Ubuntu runs much more like it would natively, thanks to various optimizations found in the kernel module that is installed as part of the Guest Additions. They help the guest OS better communicate with the virtual machine. There are many technical reasons why the kernel modules makes this work, but that’s a bit out of the scope of this article. Just know that installing them does help.
Installing The Guest Additions
Installing the Guest Additions is quite simple, really. There’s nothing you have to download, as they come with your VirtualBox installation. All you need to do is boot up your desired virtual machine, and then choose Devices -> Insert Guest Additions CD image. This will insert an ISO image into the virtual CD drive attached to the virtual machine, which should start an autorun prompt.
In Windows, it should install with ease thanks to the installer. In Linux, you’ll need to enter your password before the installer takes care of the rest. However, it’ll only work well if you make sure you have gcc, g++, dkms, and kernel-devel installed.
In Ubuntu, before choosing to install the Guest Additions, you just need to run the terminal command:
sudo apt-get install gcc g++ dkms
In Fedora, the command would be:
sudo yum install gcc g++ dkms kernel-devel.
Using Guest Additions
As you can see, it’s well worth installing the Guest Additions in your guest OS to get the best possible experience with VirtualBox. It only takes a few moments and a quick restart, so there’s little reason not to do this. Honestly, the only reason might be because you’re just quickly testing an operating system before removing it again, but even then it’d be worth installing the Guest Additions for the performance boost.
How often do you use VirtualBox or another virtual machine package? Do you know any cool tricks you can do with them? Let us know in the comments!