After news broke more than a year ago regarding Microsoft's plans to develop an XML programming language, company officials abruptly stopped talking about the so-called X# language. Some claimed Microsoft had killed the language. Others said Microsoft had temporarily shelved it.

It turns out that X# is alive and well – and is now going by the code-name "Xen."

Microsoft X# on Tap

Microsoft's New 'Xen' Programming Language in the Works

Erik Meijer, a former Microsoft researcher and now a technical lead with Microsoft's Webdata group, confirmed that Xen and X# are one and the same.

"We found the name X# caused too much confusion around C#," said Meijer, explaining the name change. "What really matters is that we are doing research in data integration in programming languages."

While Meijer presented a paper on Xen to attendees of the XML 2003 conference in Philadelphia in December, Microsoft has declined repeated requests to discuss the language.

XML Messaging Architect Don Box was one of the first to hint, back in December 2002, that Microsoft was working on an XML programming language. But when asked late last year about the status of X#, Box wouldn't say much.

"The ideas put forth by X# have influenced a lot of people inside of Microsoft," Box told Microsoft Watch. "Beyond that, I'm not plugged into the product plans around X#.

Read the Full Don Box Q&A

There are a few white papers and other documents available on the Web that detail some of the principles behind Xen. Xen is described by some as "the hypothetical extension of C#." Others describe Xen as an amalgamation of Microsoft's Common Language Runtime (CLR), XML and SQL programming languages.

"The integration of data access in mainstream programming languages is of particular importance — millions of programmers struggle with this every day," according to a white paper from last year, entitled "Unifying Tables, Objects and Documents," coauthored by Meijer and Microsoft researcher Wolfram Schulte.

With Xen, Microsoft is working to show that it's possible to feature both SQL tables and XML documents as "first order citizen(s) in an object-oriented language," the paper continues.

C#, the brainchild of Anders Hejlsberg, a Microsoft distinguished engineer and chief C# language architect, is considered by many as Microsoft's alternative to Java.

For More Details on Xen, See ExtremeTech's Xen Explainer Here

Microsoft Research is collaborating with the University of Cambridge U.K. on Xen. As with all MSR projects, there is no guarantee how, when or even if they will be commercialized.

While Microsoft will be updating C# later this year as part of its overall "Whidbey" Visual Studio update, it doesn't appear that any elements of Xen will be part of the new tool suite. Microsoft has said that the Whidbey Visual Studio release will be delivered before the end of calendar 2004.

But it also seems that Meijer and the Webdata team are working actively to advance Xen. The Webdata team was formed in the late 1990s, when Microsoft merged its XML and Microsoft Data Access Component teams. The team has been working to help various units at Microsoft develop and deliver relevant XML Web services.