When Bob Hecht joined Informa as its vice president of content strategy, he dreamed of rebuilding the London-based technical publishing firm's IT infrastructure, using Linux and other open source technologies.

But with Windows entrenched throughout the company, Hecht settled on a more pragmatic hybrid approach: an open source content management server from Alfresco Software, backed up by open source applications MySQL, Apache Tomcat and JBoss -- all running on top of Microsoft's Windows Server operating system.

Open source desktop technologies, such as the Open Office application suite and Firefox Web browser, have long had their greatest uptake from Windows users. Back-end software has been a different matter, though.

Microsoft and open-source vendors have portrayed the choice of which products to use as a black-and-white decision: Microsoft's all-inclusive .Net infrastructure or the LAMP stack, which includes Linux, the Apache Web server, the MySQL database and either the Perl, Python or PHP programming language.

But Hecht is part of a growing wave of users opting for a third way that some have dubbed WAMP. Advocates of the Windows-based approach say that it provides the best of both worlds.

"Would I want to put it all on Linux? Yeah, that's the geek in me," Hecht said this month. "But the Alfresco application doesn't necessarily run better under Linux."

And although the need to license Windows may make the new content management system more expensive than it would have been with Linux-based hardware, not having to hire additional IT workers or retrain existing staffers to support the open-source operating system makes "the whole thing a wash" financially, Hecht said.

Informa is currently running the system in pilot mode.

Faced with the allure of open source applications among its customer base, Microsoft has toned down its .Net-only rhetoric. "It's a myth that open source and Windows can't work together," said Ryan Gavin, a director of platform strategy at Microsoft. "Customers just aren't religious about these things."

Many open source vendors continue to make products that work best or only on Linux, but some are questioning the previous decisions to ignore the Windows market.

Don't ignore Windows

"As an open source vendor, we believe in choice," said Ram Venkataraman, director of product management for JBoss.

The company has said that half of its customers run its application server software on Windows. And despite its acquisition by Linux vendor Red Hat in June, JBoss doesn't plan to cut Windows users out of the picture, Venkataraman said.

"It's important for Java deployments to run on Windows," he said. "If you look at Web services, it's all about interoperability."

The need to interoperate and cut costs led Sherwin Lu of La Petite Academy to install the JBoss software on top of Windows Server 2003 last year.

Lu, director of application infrastructure at the Chicago-based preschool chain, said moving from a Visual Basic 6 development environment to J2EE "felt a little risky." But the cost of training his staff on J2EE was about the same as it would have been if he had upgraded to a .Net infrastructure.

Moreover, by adopting JBoss rather than proprietary application servers, Lu figured that he saved about $1 million in licence fees alone. And he said that by staying on Windows, he avoided the pain and cost of hiring an all-new systems administration and support team.

In another sign of the growing interest in WAMP setups, at least 12 bundles of the required open source products are now available to be downloaded and installed on Windows servers. For example, the XAMPP installer created by Berlin programmer Kai Seidler is available for Windows as well as for Linux and other operating systems, including Solaris and Mac OS X.

Thus far, more than 80 percent of its three million downloads have been made by Windows users, Seidler said. Even Web servers -- a long-time sweet spot for the LAMP stack -- are increasingly being run on Windows hardware, according to Mark Brewer, CEO of Covalent Technologies.

Covalent provides support services to users of The Apache Software Foundation's open-source products. Brewer said almost one-third of the customers his company supports on the Apache Tomcat server are running the software on Windows.

"That had been 15 percent to 20 percent historically," Brewer said at last week's O'Reilly Open Source Convention in Portland, Ore.

In addition, nearly one-fifth of Covalent's customers run Apache's flagship Web server on Windows. Brewer said he thinks that figure is equally significant, considering that Microsoft bundles its Internet Information Server software with Windows Server.

But Microsoft's ability to integrate its own back-end products with Windows gives it a big edge over open source insurgents in general, said Mike Olson, vice president of embedded technologies at Oracle and former CEO of Sleepycat Software.

Sleepycat, which Oracle acquired in February, developed the open source Berkeley DB embedded database. But, Olson said, "if I've already got Microsoft [technology] installed on my Windows server box, why would I bother to throw it away and install something else?"