Updated: October 27, 2010
This sounds a seemingly trivial task. Why would I want to write a tutorial about this? Well, it turns out that sometimes in between Oracle takeover of Sun and the increment of VirtualBox versions from 3.0.x to 3.2, the Settings menu has changed and the CD-ROM option as an individual category was dropped and merged into Storage. This makes booting from CD so much more difficult for less skilled users.
Instead of being able to boot from CD-ROM and install their virtual machines, users are left baffled, wondering how they can get the CD-ROM device enabled and configured in VirtualBox. Not to worry, I'm here and I'm going to show you exactly that.
Notice the CD-ROM category, fifth from above.
And if you expand, it's extremely simple to configure the device.
In the latest version at the moment this article has been written, 3.2.8, this is no longer the case. The functionality has been moved away into a different category.
Let's learn how we can rectify this rather geeky change.
Take a look at the Storage category. It replaces the Hard Disks and CD/DVD-ROMs sections. Click on it to expand.
The middle pane is called Storage Tree. This is what we want to look at.
Here you can define device controllers. VirtualBox will let you define either IDE controllers or SATA controllers. IDE controllers can be used for both CD-ROM and hard disk devices. SATA controllers will only be used for hard disks. This means, up to four IDE devices and up to 15 SATA devices.
You will mostly have one controller already present, with a hard disk of your virtual machine listed just underneath. Click on the controller itself.
New icons will appear. For IDE controllers, two in the same line as the Controller, several more at the bottom. These plus and minus icons allow you to add/remove controllers and devices. For SATA controllers, you will only have one icon at the top.
For IDE controllers, the two icons at the top allow you to add either a CD-ROM or a Hard disk device to your existing controller. So if you have none listed of any desired type or you need more, e.g. two hard disks, just click on the icon and a device will be listed.
Similarly, at the bottom of the middle pane, you can remove controllers altogether or devices listed underneath. In a way, the dual commands are a little confusing.
What you need to focus on are the top icons (or the top icon, for SATA). Create a new CD-ROM device. That's the icon on the left. Then, let's take a look at the right pane.
Click on the little icon to the right of the CD/DVD Device: to expand and choose the right device. You may select your physical device, use the VirtualBox Guest Additions .iso if you're planning on installing the Guest Additions in your virtual machine, or any other operating system image.
Note: ISO images will need to be mounted first, i.e. added to the list of storage devices used by VirtualBox. Again, this is not an elegant or intuitive solution and you can read more about in my How to add disks in VirtualBox tutorial.
You can repeat this separately for different controllers and different CD-ROM devices, using some with physical devices, others with ISO images. Finally, the Passthrough option can be checked for real CD-ROM devices, allowing you to burn data to CD/DVD inside your virtual machines.
And basically, that's it. Now you can boot from CD-ROM. Of course, make sure that you have enabled CD-ROM in the General category. All is well now and you're back to enjoying this fine virtualization product.
For a whole library full of tutorials, guides, howtos, tips and tricks on virtualization, feel free to click on any of the links below, preferably all.
I really wonder which autistic slash oligophrenic geek decided to implement this change. Yes, it does make sense from the technological point of view, since it allows you to display all your storage devices in a clear hierarchy tree, but it makes one hell of a usage, in a negative sense, for the common user. Perhaps, average people should not be using virtualization, but there are more blunt ways of telling them that.
Anyhow, you have now learned something new and quite important. You can still continue booting from CD-ROM in newer VirtualBox versions. You can create IDE and SATA controllers. CD-ROMs can only be assigned to IDE controllers, one per each. For every CD-ROM device, you can assign a physical drive or an operating system image, but the images will need to be mounted first, so to speak. Now, this could turn out to be a new kind of obstacle, and if it does, I will write yet another tutorial.
I hope you liked this. Enjoy the virtual computing!