Company officials say they've been here before and won't flinch.

"That is how Red Hat has grown up, battling titans," says Mike Evans, the company's vice president of corporate development. "We have built out the operating system, we have been building the network management, adding security and other things and it was a big bite for Red Hat to acquire JBoss and get into the middleware market and battle some more titans."

The $328 million JBoss acquisition put the company onto a whole new layer of the software stack, a place it failed to thrive with an earlier project around the Java Open Application Server (JOnAS) that never attracted a legitimate user base.

The current JBoss Enterprise Middleware Platform is about providing a common set of open source tools to create a foundation that will support software components and applications, a similar model Red Hat used with its operating system.

The platform includes the JBoss Enterprise Application Platform, a stand-alone offering that runs on Linux or Windows and the similar Red Hat Application Stack, which comes bundled with RHEL 5. The platform also includes the JBoss Enterprise Portal Platform.

And like the operating system, Red Hat wants to create a JBoss community.

Earlier this year, it established JBoss.org, an open source project to spur innovation that can migrate into the enterprise platform.

The relationship is much like RHEL and Fedora, the open source project around the operating system. Red Hat also built a support structure for patching, upgrades and general maintenance called JBoss Operations Network that mimics its Red Hat Network.

"Red Hat wants to be regarded as an SOA suite powerhouse," says Jim Kobielus, principal analyst for data management at Current Analysis. "But the JBoss stack is very much a work in progress and components are missing for them to contend with the likes of Oracle, IBM and BEA."

Kobielus says those components include ETL (Extract, Transform, Load), and event stream processing on the data integration side and business intelligence tools on the portal side.

Red Hat owns up to those challenges as evidenced by its April acquisition of MetaMatrix, a platform for integrating disparate data source into Web-based applications.

Red Hat customers are taking a shine to the JBoss possibilities but also evaluating how the entire open source stack fits together.

"On the application layer with JBoss, Apache Web Server and MySQL, I want to see how Red Hat is making these three separate worlds come together as one offering," says Ravi Simhambhatla, director of architecture and integration for Virgin America. "That is going to be critical for me to make some decision going forward."

To date, Virgin America, which took to the skies for the first time in July, is confident having already built its commerce and corporate infrastructure on RHEL, but its middleware is still in flux as it plans an October migration from Apache Tomcat application server to JBoss.

Red Hat's efforts to build around JBoss is but one in a set of interwoven transitions designed to create an enterprise infrastructure platform, including its first serious attempt to woo Java developers, its first virtualization technology and its first marketplace to support a host of open source applications certified to run on that platform.

In fact, Red Hat's expansion efforts have resulted in a 73 percent increase in its R&D budget from $40.9 million in fiscal 2006 to $71 million in fiscal 2007.

And those numbers are likely to rise in fiscal 2008.

Last month, the Red Hat Developer Studio went into beta. It is a set of eclipse-based development tools that are preconfigured for the JBoss platforms.

"Linux as a server is going well beyond the fringe applications," says Paul Cormier, executive vice president of engineering at Red Hat. "It is going into the core and when you start to penetrate into the core of business applications you need a strong developer platform. That is what this is all about."