Still, Microsoft CEO Steve Ballmer continues his sabre rattling, warning that users of Red Hat Linux software have an "obligation" to pay Microsoft because there's some Microsoft-owned code in there.

Craig Mundie, Microsoft's CTO, called open source a failed business model on the order of the dot-com boom that went bust.

"It fundamentally undermines the independent commercial software sector," Mundie said, in 2001, of the GPL requiring that any software developed using GPL-covered code is also subject to the GPL. "While this type of model may have a place, it isn't successful in building a mass market."

Tell that to Red Hat, which made US$69 million profit on US$463 million revenue in its 2007 fiscal year on its business model of charging for support and unique functionality of its open source Linux software.

Sun and IBM are among the converts, embracing open source while not completely abandoning their commercial software businesses.

Open source is on a roll. A Saugatuck Research survey showed nearly 50% of businesses plan to use Linux for mission-critical systems by 2012, vs. just 18% in 2007.

Although some of its growth is misdirected, with way too many Linux distributions out there, open source is cited as one of the top 10 "flatteners" in Thomas Friedman's 2005 book The World is Flat: "Open-source ... makes available for free many tools that millions of people would have had to buy in order to use.

Open-source network [communities] can challenge hierarchical structures with a horizontal model of innovation." -Robert Mullins

Novell NetWare vs. Microsoft networking

If it weren't for Novell's Ray Noorda taking his eye off the networking ball in favor of chasing the corporate desktop, Novell's NetWare might still be a powerhouse network operating system.

At the height of its success in the early 1990s, NetWare commanded more than 70% of the market and a loyal customer base drawn to the product for its file sharing prowess, reliability and performance.

NetWare, which was developed as a contracted project by a few computer science graduates of Brigham Young University, debuted in 1981. "The product was originally known as ShareNet," says Drew Major, a founder of Novell and often referred to as the Father of NetWare. "NetWare was more of a continuation of the 'ware' part of the various computer terms of the time -- [software and hardware] -- and since no one was really doing much networking yet we could have a name that was in a sense generic yet proprietary to us and our position."

In 1985 Microsoft, the vendor of the popular MS-DOS desktop operating system -- launched a weak alternative to NetWare called Microsoft MS-NET. Later, Microsoft introduced LAN Manager in response to NetWare's market success. Microsoft even teamed with IBM on OS/2 LAN Server to counter NetWare. It wasn't until 1994 when a persistent Microsoft introduced Windows NT Server that the tables took on a decidedly Microsoft slant.

When Novell acquired SUSE in 2003 and with it a Linux operating system distribution, the NOS market started shifting again.

To pull the company out of its doldrums, Novell introduced Linux to its NetWare customers and blended NetWare with Linux via a product called Open Enterprise Server. Now, four years later, hundreds of NetWare networks are using Linux for applications as diverse as Web, database and application servers and NetWare services running on top of Linux may take a while to disappear from the corporate landscape.

The companies, worn down by decades of battling over the NOS market, this year actually began collaborating on network operating systems, building each others' technologies into their products. -Deni Connor