In February 2008 Sun acquired the German company innotek, obtaining control on two virtualization platforms: VirtualBox, an open source hosted VMM for desktops, and hyperkernel, a bare-metal VMM (aka hypervisor) that was still in private beta.
There is the maximum secret around hyperkernel: innotek never disclosed any detail about its architecture (despite there are some good hints available), and nobody ever provided a feedback about the preliminary version available.
Sun never told which are the plans for this hypervisor but it’s easy to imagine that, if it’s good enough, it could replace the current one (Xen) in the upcoming xVM Server.
VirtualBox instead was immediately rebranded and distributed for free through the Sun website. This allowed the company to reach the remarkable amount of five million downloads in less than 4 months.
So it seems that Sun has something to compete with free virtualization veterans: Microsoft achieved 1 million downloads for Virtual PC 2007 in 38 days.