History

Late 1990s

The Xen hypervisor was first created by Keir Fraser and Ian Pratt as part of the Xenoserver research project at Cambridge University in the late 1990s. A hypervisor "forms the core of each Xenoserver node, providing the resource management, accounting and auditing that we require." The earliest web page dedicated to the Xen hypervisor is still available on Cambridge web servers.  The early Xen history can easily be traced through a variety of academic papers from Cambridge University. Controlling the XenoServer Open Platform is an excellent place to begin in understanding the origins of the Xen hypervisor and the XenoServer project. Other relevant research papers can be found at:

• Xen and the Art of Virtualization - Paul Barham, Boris Dragovic, Keir Fraser, Steven Hand, Tim Harris, Alex Ho, Rolf Neugebauer, Ian Pratt, Andrew Warfield. Puplished at SOSP 2003
• Xen and the Art of Repeated Research - Bryan Clark, Todd Deshane, Eli Dow, Stephen Evanchik, Matthew Finlayson, Jason Herne, Jenna Neefe Matthews. Clarkson University. Presented at FREENIX 2004
• Safe Hardware Access with the Xen Virtual Machine Monitor - Keir Fraser, Steven Hand, Rolf Neugebauer, Ian Pratt, Andrew Warfield, Mark Williamson. Published at OASIS ASPLOS 2004 Workshop
• Live Migration of Virtual Machines - Christopher Clark, Keir Fraser, Steven Hand, Jacob Gorm Hansen, Eric Jul, Christian Limpach, Ian Pratt, Andrew Warfield. Published at NSDI 2005
• Ottawa Linux Symposium 2004 Presentation
• Linux World 2005 Virtualization BOF Presentation - Overview of Xen 2.0, Live Migration, and Xen 3.0 Roadmap
• Xen Summit 3.0 Status Report - Cambridge 2005
• Introduction to the Xen Virtual Machine - Rami Rosen, Linux Journal. Sept 1, 2005
• Virtualization in Xen 3.0 - Rami Rosen, Linux Journal. March 2, 2006
• Xen and the new processors - Rami Rosen, Lwn.net. May 2, 2006

Over the years, the Xen community has hosted several Xen Summit events where the global development community meets to discuss all things Xen. Many presentations and videos of those events are available here.

2002

The Xen hypervisor was open sourced to allow a global community of developers to contribute and improve the product.

2003

The first public release of Xen is announced at the USENIX Operating Systems Design and Implementation conference in the fall.  We regard this as the "birthday" of Xen.

2004

Xen 1.0 was officially released followed a short time later by Xen 2.0. At the same time, Ian Pratt and several other technology leaders founded XenSource, Inc. to convert the Xen hypervisor from a research tool into a competitive product for enterprise computing. As part of the corporate strategy, the Xen hypervisor remained an open source solution.

2005

Widespread adoption of the Xen hypervisor took place when Red Hat, Novell, and Sun all added the Xen hypervisor as their virtualization solution of choice. The development community also accelereted the capabilities of Xen with the Xen 3.0 release.

2006

Microsoft and VMWare adopted the concept of Paravirtualization, first introduced by the Xen community.

2007

Citrix Systems, Inc. acquired XenServer in August for $500 million.
“This announcement represents a key milestone for the Xen project,” said Ian Pratt, leader of the Xen project and co-founder of XenSource. “Citrix is committed to our community and the principles of transparency and neutrality that allow us to work together on the reference standard for virtualization, promoting the rapid, ubiquitous adoption of virtualization.”

2008

The Xen ARM project is created by Samsung Electronics.

2009

The Xen community announced a new initative for Cloud Computing, Xen Cloud Platform.

2010

The Xen community releases Xen 4.0.  In early 2010, a community contest was held to create the Xen mascot. The official mascot was launched in June 2010.

2011

Linux 2.6.37, is the first upstream Linux kernel that canboot on Xen as Dom0 out-of-the-box.

The Xen community delivered the first version of the Xen Cloud Platform.

Linux 3.x, contains full support for Xen Dom0 and DomU. Major Linux distributions announce that they will re-introduce Xen into their distributions.

Project Kronos is created to deliver XCP supporting Debian and Ubuntu as Dom0, as well is being distributed via Linux distributions.

First Xen prototype for XenARM using Cortex A15 is announced.

2012

The Xen Cloud Platform packages for Linux are released.

2013

The Xen ARM port becomes functional.

Xen becomes part of the Linux Foundation as a Linux Foundation Collaborative Project.  The community website is transitioned from Xen.org to a more modern website at XenProject.org, and the new trademark "Xen Project" is issued to the Linux Foundation.