Oracle is doing virtual machine too.

Recently, I happened to notice an article introducing Oracle VM. I was thinking Oracle bought a VM company.  http://www.oracle.com/technologies/virtualization/index.html
After browsing the  whitepaper and introduction, I noticed it's Oracle's own VM. The most interesting thing I noticed of Oracle VM is it's installation. The introduction said this VM needs no host operating system. In its installation guide, it says the installation of such VM will remove the existing operating system. In this same docuement, it says Oracle has its VM solution in its Oracle enterprise linux. So I think Oracle might have built this VM based on its Linux. But I didn't download the installation disk due to limited bandwidth in company and most importantly, due to lack a spare pc to install it.
This VM support windows and linux guest OS as stated in its homepage.
Quite a lot of Oracle softwares are already certified to run on this VM.
So far as I know, there are three players in VM world, they are VMware, MS virtual PC and this Oracle VM. The previouse two both can install on a host OS.