These days it comes as part of Windows 10 Pro and Windows Server (20), at no additional cost to the user. Originally codenamed Viridian, and then Windows Server Virtualization, it was rebranded to Hyper-V Server when it was first released in late 2008. Read our full Xen Project review (opens in new tab). A key emphasis is on security by using as small a code base as possible, making it not just secure but especially flexible. The service is especially applicable for hyperscale clouds, and can easily be used with AWS, Azure, Rackspace, IBM Softlayer, and Oracle.
The Xen Project software is even being used in automotive and aviation systems. This includes but is not restricted to Infrastructure as a Service (IaaS) applications, desktop virtualization, and security virtualized. It is especially used for advanced virtualization, not least for servers, in both commercial and open source environments. The Xen Project now works with The Linux Foundation in promoting open source applications. Originally developed by Cambridge University, the staff who created it spun it into a company that was later acquired by Citrix. Xen Project is a free and open source virtual machine monitor (VMM), intended to serve as a type-1 hyperviser for multiple operating systems using the same hardware.
