"Virtualization is already widely used, but primarily for the first-order benefit, namely server consolidation," notes Citrix CTO Simon Crosby, in this Exclusive Q&A with SYS-CON's Virtualization Journal in the run-up to next month's 3rd International Virtualization Conference & Expo in New York, at which he is a speaker. "The second-order benefits of agility, availability and manageability of the IT stack are now becoming better understood," Crosby continues, "and as a consequence virtualization has moved from a tactical tool for gaining immediate savings, to become a key strategic theme for every IT department."
About Simon Crosby: Now CTO of Citrix Systems, Simon Crosby was founder and CTO of XenSource prior to the acquisition of XenSource by Citrix. Prior to XenSource, Simon was a principal engineer at Intel where he led strategic research in distributed autonomic computing, platform security and trust. Previously, he was the founder of CPlane Inc., a network optimization software vendor, where he held a variety of executive roles. Before joining the private sector, Simon was a tenured faculty member at the University of Cambridge, UK, where he led research on network performance and control, and multimedia operating systems. He is author of over 35 research papers and patents on a number of datacenter and networking topics including security, network and server virtualization, resource optimization and performance. In 2007, Simon was awarded a coveted spot as one of InfoWorld’s Top 25 CTOs.
Virtualization Journal: Starting at 35,000 ft…where does the Xen hypervisor fit in the virtualization universe?
Simon Crosby: The Xen hypervisor is the industry’s most strategic code base for virtualization. Why? First, it is a tiny, optimized, open source reference standard hypervisor for a wide range of CPU architectures, with extensive support for high performance virtualization-enhanced CPUs and I/O subsystems. Because it has multiple routes to market in any given year, the hardware manufacturers ensure that Xen has “first and best” support for the latest hardware, ensuring that it always leads the industry in scalability and performance. In addition:
It is collaboratively built by the industry’s leading IT vendors, led by Citrix and including Intel, AMD, IBM, HP, Novell, Red Hat, Sun, VA Linux and many others.
The Xen security architecture is contributed by the security community, including researchers, IBM’s secure hypervisor project, the NSA and DoD.
Xen is used in the world’s largest virtualization deployments, for example by Amazon, with a deployment of thousands of servers virtualized using Xen.
The Microsoft Hyper-V hypervisor is in fact an implementation of the Xen reference architecture, built by Microsoft, and compatible with Citrix XenServer.
Virtualization Journal: The first public release of Xen was made available in 2003, how long did it take for you and your Cambridge collaborators to get it to that stage?
Crosby: The Xen code base has been in development now for seven years. When we started XenSource, we had released Xen 2.5, and were working on Xen 3.0.
Virtualization Journal: What was and is the relationship between XenSource, Inc. and the Xen project?
Crosby: XenSource’s founders – all former University of Cambridge faculty who developed Xen in their research – decided that the Xen hypervisor needed a company to support its ongoing development when large users of Xen told us that we needed to build a complete product offering based on Xen so they could be confident that their commercial deployments would have the backing of a commercial entity.
About Jeremy Geelan Jeremy Geelan is Sr. Vice-President of SYS-CON Media & Events. He is Conference Chair of the AJAXWorld RIA Conference & Expo series, of the all-new Cloud Computing Conference & Expo, of the 4th International Virtualization Conference & Expo and founder of Web 2.0 Journal, AJAX & RIA Journal and other major SYS-CON titles. From 2000-6, as first editorial director and then group publisher of SYS-CON Media, he was responsible for the development of all new titles and i-Technology portals for the firm, and regularly represents SYS-CON at conferences and trade shows, speaking to technology audiences both in North America and overseas. He is executive producer and presenter of "Power Panels with Jeremy Geelan" on SYS-CON.TV.
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"Virtualization is already widely used, but primarily for the first-order benefit, namely server consolidation," notes Citrix CTO Simon Crosby, in this Exclusive Q&A with SYS-CON's Virtualization Journal in the run-up to next month's 
