Sun announced this week the availability of VirtualBox 3, the latest version of its open source virtualization solution. The new version introduces experimental 3D graphics support and the ability to expose multiple CPUs to guest operating systems.

VirtualBox was originally developed by InnoTek, which was acquired by Sun last year. InnoTek launched an open source edition of VirtualBox in 2007, releasing most of the program's code under the GPL. Alongside the open source version, the company has continued to sell a commercial version that has additional features, such as a built-in RDP server and full USB support. VirtualBox is cross-platform compatible and is available for Linux, Windows, and Mac OS X.

The software has matured quickly and is beginning to outpace its rival VMware Workstation in many ways. VirtualBox is becoming especially popular on the Linux platform because its open source licensing makes it easy for Linux distributors to package and deploy—and it generally performs better than Linux's kernel-based Virtual Machine (KVM), the native virtualization solution of the Linux kernel. It also has an excellent user-friendly configuration and VM management interface.

VirtualBox provides relatively good integration between the guest environment and host environment. It can do clipboard and folder sharing and can dynamically adjust the guest environment display resolution as the guest window is being resized. One of its most advanced capabilities is a "seamless" mode which allows users to break the windows out of a guest environment and mix them with the windows of the host environment, similar to the Unity feature of VMware Fusion.

VMware still offers a few advantages, such as better support for snapshots. One of the key differentiators of VMware was its support for virtualized SMP, but this feature was finally introduced in the latest version of VirtualBox. In VirtualBox 3, you can expose up to 32 CPUs or CPU cores to a guest environment (this requires chips that support Intel's VT-x extension or AMD-V).

The VirtualBox developers have gradually been adding support for accelerated 3D graphics. VirtualBox 3 has relatively solid support for OpenGL on Windows and Linux guests. It also has gained experimental support for Direct3D 8 and 9 on Windows. These advancements could make VirtualBox a viable solution for 3D gaming. I've been testing VirtualBox's 3D graphics support with Linux guests since the 2.2.4 release in May. The Compiz compositing window manager will now work out of the box in Ubuntu guest environments, complete with wobbly windows and 3D cube action.

In addition to support for SMP and 3D graphics, VirtualBox 3 also resolves a host of bugs, including fixes for suspend/resume on Solaris hosts, fixes for PAE on Mac OS X, and fixes for shared X11 clipboards in Linux guests.

VirtualBox is currently my preferred desktop virtualization solution. I made the jump from VMware Server last year after losing patience with VMware's lousy Linux support. I use VirtualBox nearly every day for distro testing and software development, and it has made virtualization an integral part of my workflow.

For a complete overview of bugfixes and other improvements in VirtualBox 3.0, see the official changelog.