The long view on Longhorn

In its first preview at the Microsoft Professional Developers Conference last fall, Windows XP successor Longhorn was shown running a 20-year-old copy of Visicalc. Ancient DOS software won't be the lone occupant of the Longhorn compatibility box. Win32, the Web, and even WinForms -- the .Net era's first GUI framework -- are all legacy APIs from Longhorn's perspective. Their replacements, Microsoft says, will jointly deliver "the best of Windows and the best of the Web."

The proof is still years away. But given the ambitious scope of the project, it's not too soon to consider how Longhorn will affect the vast majority of enterprises deeply invested in both Windows and the Web. How will the transition to Longhorn affect these twin legacies? Which aspects of the new system will embrace open standards, and which will entail lock-in? Will the benefits of the proprietary features outweigh cost? The answers differ for Longhorn's several subsystems; we'll consider each in turn.

One thing that's not in question, however, is Longhorn's deep commitment to .Net. The last time Microsoft said it was betting the company on managed code, the claim was heavy on marketing and short on substance. This time there's no wiggle room. Longhorn is deeply tied to the .Net Framework. Although its three "pillars" -- Avalon for presentation, WinFS (Windows File System) for storage, and Indigo for communication -- will rely on a mix of managed and unmanaged services, those pillars will export only managed APIs for use by Longhorn applications. That's great news for the long-term health of Windows, the productivity of its developers, and the security of its users.

To deliver these benefits, Microsoft is aiming a few years ahead of the hardware curve. Few of today's PCs and none of today's handhelds are likely targets for Longhorn.

Although the project may someday unify Windows, in the near term it will surely compound the already problematic fragmentation of the platform. As if that weren't headache enough, Microsoft's vote of no confidence in the future of many basic Web standards puts the company on a collision course with competitors who continue to invest in those standards -- and with customers who would like to see Web standards supported and advanced.

It's an aggressive and risky strategy. To appreciate the payoff, you can't just consider Longhorn's features individually, Microsoft says. The value of the system as a whole, the company insists, will exceed the value of the sum of its parts. Concept videos paint the big picture. In one of them, a real-estate broker uses Avalon's 2-D and

3-D graphics to visualize map data, WinFS metadata and contacts to assemble and share a package of information, and Indigo's XML messaging to tap into Web services and to collaborate peer-to-peer with investors and lenders. In the Longhorn-only world of the demos, rich-client applications flow to PCs on demand using the ClickOnce feature that will debut in the forthcoming .Net Framework 2.0, aka Whidbey.