When Bob Hecht joined Informa as its vice president of content strategy, he dreamed of rebuilding the British technical publisher's infrastructure using Linux and open-source technologies. But with Microsoft Windows entrenched throughout the company, Hecht settled on a more pragmatic hybrid: an open-source content management server from Alfresco Software, backed up by open-source applications MySQL, Apache Tomcat and JBoss -- all running on Windows Server-based hardware.

"Would I want to put it all on Linux? Yeah, that's the geek in me," Hecht said at this week's O'Reilly Open Source Convention in Portland, Ore. "But the Alfresco application doesn't necessarily run better under Linux."

And although the Windows licenses may make the initial costs a little more expensive for Informa, not having to rehire or retrain existing IT staff makes "the whole thing a wash," he said.

While open-source applications such as the OpenOffice productivity suite and the Firefox Web browser are aimed at Windows users, back-end software used by businesses is a different matter. Both Microsoft and open-source vendors have traditionally portrayed the choice of whether to use their software as a black-and-white decision. Choose Microsoft Windows' all-inclusive .Net infrastructure, or run the LAMP stack of applications, which includes Linux, the MySQL database, the Apache Web server and one of three programming languages starting with the letter P: Perl, Python or PHP.

One choice promises easier management at a higher price. The other offers lower costs and better security -- at the cost of more complexity.

But Hecht is part of a growing wave of IT users opting for a third way some have dubbed WAMP (Windows, Apache, MySQL and Perl/Python/PHP). They say it provides the best of both worlds.

"It's a false but longtime perception [of] an either/or choice," said Bob Shimp, vice president of open-source for Oracle Corp. In addition to pushing Linux as its preferred database platform, Oracle has snapped up a number of open-source vendors in the past nine months. "Commercial and open-source products are highly complementary," Shimp said. 'Frankly, a lot of people in the open-source community have done themselves a disservice by painting things" as either/or decisions.

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

Users now have a variety of 12 WAMP packages they can download and install on Windows servers. Take the XAMPP installer, created by Berlin programmer Kai Seidler. Though XAMPP is available for operating systems such as Apple Computer Inc.'s Mac OS X, Sun Solaris and Linux, more than 80 percent of its 3 million downloads have come from Windows users.

Although many open-source vendors continue to make products that work best on Linux, some are also questioning a decision to ignore the huge Windows market.

"As an open-source vendor, we believe in choice," said Ram Venkataraman, director of product management for JBoss. Half of JBoss' customers run Windows. And despite JBoss' acquisition by Linux vendor Red Hat Inc. earlier this year, Venkataraman said the company has no plans to cut out its Windows users.

"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, director of application infrastructure for Chicago-based preschool chain Le Petite Academy, to upgrade to the JBoss application server on top of Windows Server 2003.

"It felt a little risky" to move to J2EE from a Visual Basic 6 environment, Lu said. But the cost of training his staff was about the same as it would have been if he had upgraded to a .Net infrastructure. Moreover, by adopting JBoss over other proprietary application servers, Lu figures he saved about a million dollars in license fees alone. And by staying on Windows, he avoided the pain and cost of "rehiring my entire sysadmin and support team."

Even Web servers -- a longtime sweet spot for the LAMP stack -- are increasingly being run on Windows.

According to Mark Brewer, CEO Covalent Technologies, almost a third of the customers it supports on the Apache Tomcat application server are running it on Windows.

"That had been 15 percent to 20 percent historically," Brewer said. Almost a fifth of Covalent's customers also run the Apache HTTP Web server on Windows, which Brewer considers equally significant, considering that Microsoft bundles a competing product, Internet Information Server, with Windows Server. More than ideology, that factor -- that Microsoft makes a huge number of business applications, a number that is only increasing -- could eventually limit the growth of open source on Windows.

"If I've already got Microsoft installed in the box, why would I bother to throw it away and install something else?" said Mike Olson, vice president of embedded technologies for Oracle and former CEO of Sleepycat Software. Sleepycat, before it was acquired by Oracle in February, made an open-source embedded database that competed with Microsoft. "It's a friction-y thing to have to do," Olson said. "So as long as it doesn't suck, you're going to stick with what you've got."