Sun Microsystems' xVM VirtualBox desktop virtualization software is now available in Release 2.2, which supports the Open Virtualization Format, or OVF, a public standard.

With OVF support, a VirtualBox virtual machine can be exported off a desktop and moved to a server to run under a different hypervisor. A VM converted to OVF-formatted files can be recognized by VMware's ESX Server, Citrix Systems' XenServer, or Microsoft's Hyper-V. OVF, however, isn't a neutral runtime format. Each hypervisor, once it recognizes the OVF format, converts the imported files into one of its own virtual machines.

VirtualBox is frequently used on PCs and workstations to create an environment in which to develop an application. VirtualBox will work with Windows, Linux, Apple's OS X, Solaris, or OpenSolaris, making it a flexible development environment. An application developed under VirtualBox can be packaged with an operating system in the OVF format, then shipped out to run in the data center on a server, or shipped elsewhere to another data center or external cloud.

Sun acquired the VirtualBox technology in 2007 and made it available for free download in October of that year. Since then it has counted off 11.5 million downloads. They continue to occur at the rate of 25,000 a day, said Andy Hall, senior xVM VirtualBox product manager, making it one of the most popular open source code choices on the Sun site. MySQL, the open source database, still enjoys a download rate more than double that of VirtualBox.

Sun has increased the capabilities of VirtualBox so that a VM being run by it can use up to 16 GB of memory, more than four times the former limit, allowing for more powerful applications, Hall said in an interview.

VirtualBox has stronger support for displaying 3-D graphics with its support for OpenGL graphics acceleration. "You can run Google Earth inside a virtual machine and make use of the host system's graphics acceleration," said Hall.

"A whole new class of applications can be virtualized that couldn't be before," he added.

VirtualBox virtual machines can be packaged as virtual appliances and shipped elsewhere for use through the JumpBox set of tools. JumpBox uses open source software to generate virtual appliances and has partnered with Sun to support VirtualBox, said Hall.

VirtualBox will support Apple's 64-bit Snow Leopard operating system when it becomes available, he said. By supporting more operating systems than other VM vendors, Sun will seek to make VirtualBox "the best hypervisor for the cloud," he added.

In addition to being available for free download, VirtualBox may be purchased through an enterprise subscription based on $30-per-user annual fee.

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