Adobe Systems plans to extend its AIR (Adobe Integrated Runtime) software to Linux later this year, Adobe CTO Kevin Lynch said during the company's Engage event in San Francisco on Monday morning.

Formerly called Apollo, AIR is the company's runtime enabling RIAs (rich Internet applications) to run offline on the desktop. Right now, AIR 1.0, which debuted Monday, is limited to Windows and Macintosh systems.

"This could enable a whole new frontier of applications for Linux," Lynch said. "We're actually looking for Linux users to help us test it." The Linux version of AIR is currently in an alpha format, according to Adobe.

Lynch also stressed the company's plans to have AIR run on mobile devices. Mobile as a whole will grow in its emphasis, Lynch said. "I believe [the emphasis] is going to shift in the next few years where we're actually going to start talking about mobile first and making it work on the big screen [afterward]," Lynch said.

Asked whether AIR would be extended to Apple's iPhone, Shantanu Narayen, Adobe CEO, deferred questions on this to Adobe partner Apple.

"We're excited about seeing it on iPhones," Narayen said. He cited Adobe's plan to make AIR ubiquitous on different devices, saying, "Our goal is AIR everywhere."

Meanwhile, Microsoft in a prepared statement cited security concerns about AIR.

"There is a significant risk in letting Web applications run loose outside the browser security sandbox. [Microsoft] Silverlight applications run within the browser security sandbox," Microsoft said.

But AIR features modifications to enable applications to run securely, said Michele Turner, Adobe vice president of platforms.

"It's not that it's running wild and free on the desktop. We kind of created our own sandbox," she said.

AIR applications run with the same security model as any exe executable file. Also, AIR applications are signed by the developer, she said.

Microsoft stressed its own approach to development as an alternative to AIR.

"Microsoft offers a dramatically different approach for creating and delivering experiences in a way that aligns more with our customers' development and deployment needs. We are building a true development platform, not just a player or a browser," the company said. "This platform spans Windows to the Web and includes emerging surfaces, such as the media/living room (Xbox360, Media Center PC), as well as mobile devices. Even though each surface has differing capabilities and form factors, our platform enables easy repurposing through shared tools and project formats. Having unified tools, languages, and markup allows developers and designers to 'learn once and apply everywhere.' "

Microsoft technologies in this space include Windows Presentation Foundation and Silverlight.