A Windows World?A Windows World?

When all that happens, applications will look and behave differently. Longhorn's communications layer, called Indigo, brings something akin to a services-oriented architecture to the operating system, making it easier to build apps that use messaging and transaction capabilities in fundamental ways. Add to that Longhorn's Information Agent, which can be programmed by users to work on their behalf, jazzed up graphics, and real-time speech recognition, and you get an app environment far more sophisticated than today's Office on Windows XP.

Microsoft officials aren't saying what comes after Longhorn, but "we have a lot of people thinking about it," says Greg Sullivan, lead product manager in Microsoft's Windows client division. Things to look for: continued security improvements, pen-and-ink input, remote control, voice recognition, biometric identification, and that new file system.

Longhorn likely will be around for years to come. A Longhorn client is due in 2006 and a server version in 2007. When you consider that Microsoft supports its products for 10 years, today's first-grader will be a college freshman about the time Longhorn wanes.

As for Linux, Torvalds and his associates finished work late last year on the 2.6 kernel, which features everything from better sound quality for PCs to support for 16 or more CPUs in data-center servers. A long list of Linux-related software projects is in progress, but planners haven't articulated what will go into Linux 2.7 or when it will be released. "We're basically playing that by ear," says Andrew Morton, lead Linux kernel maintainer with the Open Source Development Lab. Meantime, developers continue to add functionality to Linux 2.6.

Torvalds, who has a fellowship with OSDL, says there could be changes to the guts of the operating system, but he's not contemplating any overhauls. "Operating systems have been around for decades, and the fact is, they don't tend to do surprising things," Torvalds says. "I suspect we'll be doing some things very differently internally, and there are bound to be new interfaces for new things people do, but in the end, an OS is an OS."

Yet, the deployment decision often involves more than the operating system. That's why the future isn't just about writing code that hums on x86 processors. Business models, software stacks, and customer attitudes will sway things, too. "I'm interested and intrigued by Linux," says Dave Zitur, CIO of Carlson Leisure Group, a satisfied Microsoft customer. Linux distributors such as Red Hat Inc. and Novell have built their base converting Unix shops. The question is how many Windows users will make the switch.

Sun Microsystems plans to reintroduce Solaris under an open-source license, which could give its widely used software new life. "Linux is Unix," Sun CIO Bill Vass argues. "There isn't a trend away from Unix; there's a trend toward Unix." IDC's Gillen says Unix will be a multibillion-dollar market for years.

Yet, it's hard to conceive how a revived Unix or the next release of Linux will derail Windows. Microsoft already has weathered one storm after another, from an antitrust suit in the United States to ongoing security vulnerabilities, and Windows sales have thrived.

Microsoft continues to invest in Windows in a substantial way, with a research and development budget this year of about $7.8 billion. To get a preview of the operating system of the future, you may only need to look as far as the PC in front of you today.

Illustration by Brian Stauffer