At present, at least a half-dozen virtualizing operating systems are on the market or in late stages of development. However, the big three are VMware, Microsoft’s Virtual Server, and Xen.
At this writing, the easiest way to experiment with server virtualization is to download VMware’s VMware Server beta version and try it. VMware Server, which will replace the company’s GSX Server, is free to download until the production version is released later this spring.
VMware is one of the pioneers of Windows virtualization, starting in the late 1990s. Its ESX and GSX VM operating systems are designed for server virtualization in data center environments. In addition, VMware offers other products for markets such as software development.
Microsoft’s Virtual Server
Virtual Server, which was released at the beginning of 2006, is Microsoft’s entry into the server virtualization market. It’s designed to run on Windows XP and Windows Server 2003.
Microsoft also has a program called VirtualPC that virtualizes the desktop. Both programs were acquired when Microsoft bought Connectix.
Xen is living proof that you don’t need a Windows hypervisor to run Windows. Xen comes out of the Linux open source community. However, by the end of 2006 Xen will be able to run Windows as a guest operating system.
Red Hat Software includes a version of Xen in its Fedora line of releases and expects to have a version that supports Windows in its enterprise server product by the end of the year.