Sun's xVM VirtualBox isn't found on as many Macs as Parallels Desktop or VMware Fusion, but Sun has ambitious aspirations for its free desktop virtualization software.

"We want to be the FireFox of virtualization," said Andy Hall, Sun's senior product manager for xVM VirtualBox.

Giving away VirtualBox away as open source software is one way to do it. In May, Sun was claiming 10,000 downloads a day for the Windows, Mac OS X, Lixux, and Solaris versions. Another strategy for Sun is to not favor any operating system, but release upgrades for all supported platforms at the same time.

"We have a fairly sophisticated massive automation system to build and test the product," said Hall. He also said that VirtualBox has a modular architecture that enables the simultaneous release.

VMware and Parallels release their virtualization products separately for each supported platform. CodeWeavers releases its CrossOver Mac and Linux upgrades together, but doesn't support as many platforms as Sun.

Since acquiring VirtualBox's developer, Innotek, earlier this year, Sun has released one major update and two maintenance updates. Sun changed the name of VirtualBox to xVM VirtualBox after the Sun acquisition of Innotek.

Although unknown to most Innotek, a German company, played a role in the development of virtualization on the Mac platform. Hall said that Innotek did some of the work for Connectix in the development of Virtual PC, a virtualization product that ran Windows on PowerPC Macs starting ten years ago. Hall said that when Connectix sold Virtual PC 6 to Microsoft, Innotek started work on VirtualBox as open source software.

Sun has retained the open source nature of VirtualBox, which is distributed under the GPL license. Sun also has two websites for the software, one at Sun.com, and the old Innotek site at virtualbox.org.

"Virtualbox.org is where the community meets," said Hall.

Inside VirtualBox

Innotek never issued what it considered a release version of VirtualBox, labeling it as a beta. But Sun considers it's first version, xVM VirtualBox 1.6, to be a release quality product, not a beta. Sun said that the version included 2000 improvements over the previous Innotek betas.

"We think it's a pretty good attempt," said Hall, although he admits that it is still missing a features that the competition has.

For instance, Hall admited that xVM VirtualBox ?behind the curve on 3D acceleration.? He added ?We don't have bridged networking or all of the components of coherence.?

Bridge networking is where the guest operating system has its own IP address, different from that of the host OS. VirtualBox currently support shared networking, in which the host and guest OS us the same IP address.

Coherence is what Parallels calls the ability to hide the Windows desktop while showing Windows applications in in windows. VMware has a similar feature called Unity.

"We haven't had that much demand [for coherence] from users," said Hall, saying that Leopard's Spaces feature is satisfying to many users.

But xVM VirtualBox also has features that Parallels Desktop and VMware Fusion don't have. Version 1.6 includes a built-in iSCSI Initiator, enabling virtual machines to access central storage facility accessed over iSCSI. Guest operating systems don't need to know about or be configure for iSCSI. The virtual machine's boot drive (C drive) can be located on the server.

VirtualBox can connect to 32 serial ADE drives, 8 times more than Parallels Desktop. And, VirtualBox also supports Gigabit Ethernet, where Parallels supports Ethernet at 100 Mbit.

So why give it away for free?

"VirtualBox is the onramp to sun's other products," said Hall. Sun's xVM line includes Sun xVM Ops Center and Sun xVM Server, that latter to ship sometime this summer. Sun also offers an OEM version for xVM VirtualBox for customers to use in their own software, including as servers.

Read more about VirtualBox on our VirtualBox Tips and Reports page.

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