Although Solaris has always been the only guest domain OS officially supported by Sun/Oracle on their Logical Domains hypervisor, , Linux (Ubuntu and Gentoo), and FreeBSD have been ported to run on top of the hypervisor (and can all run simultaneously on the same processor, as fully virtualized independent guest OSes). Wind River "Carrier Grade Linux" also runs on Sun's Hypervisor. Full virtualization on SPARC processors proved straightforward: since its inception in the mid-1980s Sun deliberately kept the SPARC architecture clean of artifacts that would have impeded virtualization. (Compare with virtualization on x86 processors below.)