Think of Linux as the beat cop of the software world. While Windows sat snugly in your office’s desktop, the open-source operating system roamed the streets and alleys of the networking world. Microsoft’s Windows minded word processing and spreadsheets. Linux served up web pages, fetched email, and powered security systems—all the kinds of jobs that put meat on your frame. More than 60 percent of the World Wide Web’s servers, for example, run open-source software.

Nevertheless, some open-source enthusiasts await the arrival of Linux on the desktop the same way fundamentalists await the Rapture. When Linux takes a big slice of the desktop market away from Windows, they argue, open source will have arrived. Linux hasn’t made the “big breakthrough,” a deal to bundle Linux with desktop systems sold by a major PC vendor. But with Microsoft stumbling in its effort to get out a new version of its Windows operating system, open-source advocates are seeing an opportunity.

At stake? Becoming the central software piece for hundred of millions of users, with all the benefits that go with that. While other gadgets sell in larger numbers, the more than 50 million PCs sold every quarter give users the ability to experiment with all kinds of applications such as file sharing, voice communications, and instant messaging. As the digital hub, the PC has to connect to everything from workaday printers to the snazziest new music players, phones, and cameras. The software that controls the personal computer gets a piece of all those innovations.

Reality CheckOpen-source evangelists say one thing. However, talk to the chief technology officers at the biggest open-source software distributors, Novell and Red Hat, and they will offer a reality check. “The Linux business from a revenue perspective will continue to be on the server for some time to come,” says Novell CTO Jeff Jaffe. “We’re where we were several years ago on the server.”

“The package of applications just isn’t there for Linux like it is for consumer Windows,” adds Red Hat CTO Brian Stevens. “In corporate controlled [PC] environments there is a [move] toward Linux, but nowhere near what is happening in corporate servers.”

The problem is that with more than 660 million PCs deployed around the world, the desktop is just too big an opportunity for open source to catch all at once. Windows and other closed-source software have been on desktops too long. Yet while that advantage may seem insurmountable, open-source software is driving from the edges of corporate networks, deeper into the business of managing serious business applications. As a result, longer term, open source isn’t going to the mainstream—the mainstream is going to open source. “You’ve got to change the value equation, and you’re not going to change the value equation by trying to re-implement Windows,” says Mr. Stevens.

That’s in large part due to open source’s origins in the networking world. Most open-source software has roots in Unix, the multi-user operating system created in the early 1970s. That software quickly became the standard for Internet-powered applications. And when Linux evolved, it adopted many of the standards behind Unix. Unix variants, such as Open BSD, took the open-source path as well, creating a deep pool of networking expertise in the open-source community. Linux’ overnight success powering network computers was really three decades in the making.

On the desktop, however, history is not on the side of open source. Office productivity software has been a staple of desktop computers since their inception. Even thousands of volunteer programs aren’t going to catch up with decades of work on, say, monitor drivers in just a few years. Windows XP’s 40 million lines of code make it compatible with a dizzying array of hardware and software options “The official industry term for it is bloatware,” quips Mr. Jaffe.

If you begin to break up the 50 million PCs sold each quarter into different categories, however, things start to look more hopeful. While home users won’t be attracted to an operating system with a dearth of gaming options, businesses see that as a plus. Mr. Jaffe likes to divide the desktop market into three broad segments: power users, information workers, and transactional users. For information workers and transactional users, he argues, the latest version of Novell’s Suse Linux can do the job at a tenth of the cost. “If we try to invest in the desktop to try to be excellent everywhere in a short amount of time, we’ll never get there,” Mr. Jaffe says.

Simplicity isn’t open source’s only advantage. Mr. Jaffe sees a future tying desktop applications more tightly to applications that live in the corporate network, such as collaboration software. The open-source community has developed a plethora of such applications, and he’s adding Novell’s collection of business management tools to the mix. Likewise, Red Hat’s Mr. Stevens sees open source moving to support the web-based applications accessed from desktops. That’s why Red Hat agreed to buy open-source software vendor JBoss, which offers software that powers such applications, for $350 million in April.

And as open-source software shifts from the edges of corporate networks to the business of running storage systems and enterprise applications, eventually the desktop itself will become another centrally managed application. Stateless Linux, a feature Mr. Stevens says Red Hat will support by year’s end, will allow businesses to run a single Linux file system that can be deployed on all of a business’s desktops. “How do you fundamentally change the equation?” Mr. Stevens asks. “You bring the cost of managing thousands of desktops down to the cost of managing a single desktop.”

Gaining Fast

In terms of productivity tools, open source is quickly gaining on Microsoft in the PC realm. More than 30 million people have downloaded the open-source OpenOffice suite of desktop applications. Novell’s Ximian software allows users to organize their email and calendaring with ease and flair. Ubuntu, a version of Linux focused on usability, has quickly become one of the most popular Linux variants. Given enough time, it’s conceivable that open-source alternatives could one day catch Windows on the desktop.

But turning open source into a Windows clone sells it short. Businesses are already shunning software that ties users too closely to their desktops in favor of hosted applications such as Salesforce.com, which has seen sales soar to $104.7 million for its most recent quarter from $64.2 million during the same period a year ago. Why recreate Microsoft Word on the desktop if in five or 10 years web-based word-processing software such as Google’s Writely begins to stunt demand for it?

Even Microsoft is turning aggressively toward hosted applications with its Microsoft Live efforts, Mr. Stevens says. Good luck with that: It’s just the kind of job an operating system stuck on desk duty might never master.

Contact the writer:BCaulfield@RedHerring.com