Xen virtualization has advanced from a promising research project to a viable open-source software that is ready for deployment. Xen-based virtualization can be divided into two main categories. First, operating systems that offer Xen virtualization as a component of an extensive range of hosting applications and services. Second, products aimed at offering Xen as a slim layer of code that converts server hardware into virtualization appliances. The second category is where Virtual Iron Softwares Virtual Iron server virtualization 3.5 belongs. The emergence of Xen has prompted Virtual Iron Software to switch to a different type of virtualization, which is dividing hardware resources into multiple virtualization appliances. XenSource, the company created by key participants of the Xen project, is also working on turning individual servers into virtualization appliances. XenSource has polished its management tool offerings and has expanded support for Windows and other unmodified guest operating systems. Novell has been promoting Xen strongly, first on its OpenSUSE Linux distribution, and recently in its production-focused SLES (SUSE Linux Enterprise Server). Red Hat recently rolled out its Red Hat Enterprise Linux 5 to show what a conventional operating system vendor cam deliver in the area of virtualization tools as part of an operating system solution. Suns Solaris is the most promising system-based program for hosting Xen, but it is also the farthest away from releasing a solid Xen host environment.