A product that provides a smooth transition between host and virtual machine helps when selecting a product for virtualization on a workstation. Sun xVM VirtualBox offers a seamless session that can make the transition between your guest and host quite transparent. The seamless window functionality is available on Windows and some Linux guest VMs for VirtualBox. The Guest Additions package is required for both platforms to use the seamless window feature.
To enable the seamless window, press the host key (which is the right CTRL key by default) and the letter ‘L’ together. VirtualBox will present the following information message before engaging the seamless Window functionality:
For Windows host systems, the VM will still reside as a separate window in the taskbar. When you select the VM in the taskbar, the active items are overlaid onto the host. For Windows systems, the guest VM desktop is not shown unless the show desktop command is sent. In the example below, a Windows Server 2008 guest VM is running in a seamless window on the Windows XP host:
This seamless functionality makes it feel less like a VM, and all keyboard and mouse operations are entirely smooth. To exit the seamless window feature, host key and the ‘L’ key together will switch the VM back to a contained window. VirtualBox can also do mixed video modes in the seamless window quite well. For example, if the guest VM is running at a 16-bit color depth, and the host is running at a higher rate the lower rate is mixed in for the VM components well.
The seamless window feature has available in VirtualBox since version 1.5. More information on VirtualBox can be found online at the Sun website.