After spending the last year lowering expectations, Microsoft pulled a rabbit out of its hat Monday and released the first beta of WinFS, the company's upcoming data storage engine. Seen as a technical albatross of sorts to company outsiders, WinFS has nonetheless been under active development for years. And now, I'm told, Microsoft feels it's time to get it out in the world and garner developer feedback.

"WinFS is alive and kicking," Tom Rizzo, the director of SQL Server product management told me Monday afternoon. "We wanted to get it out there before the PDC \[Professional Developers Conference 2005, in about two weeks\] and give developers a chance to check it out and give us feedback at PDC and beyond."

According to Rizzo, the focus for WinFS hasn't changed: It's still the foundation for a rich relational file system engine for Windows. "With WinFS, we will provide rich new ways to organize and visualize data," he said. "And as a final piece, it's a platform. It's not just for end users: Developers can extend WinFS, integrate their applications with WinFS, synchronize data between their applications and WinFS, and build support for their own data types into WinFS, using full-featured, managed code APIs \[application programming interfaces\]."

What's new with the release of WinFS Beta 1 is that Microsoft is adding support for Windows XP with Service Pack 2 (SP2). Indeed, Beta 1 only works on XP. When installed, you see a new top-level object in My Computer called WinFS Stores. Inside of this storage area, which can be accessed by any existing Windows application as if it were the native file system, you can create and organize individual data stores.

Microsoft designed WinFS Beta 1 for developers, so there really isn't a lot going on here for end users. However, it's interesting to see how well integrated the WinFS data stores are with Windows Explorer, and normal Windows applications such as Microsoft Word can store and retrieve documents there if desired. "\[Legacy shell/application\] integration is a major milestone," Rizzo confided. "It took months of work to make it seamless. Often with software, the simplest thing for users is complex underneath."

In the future, Microsoft plans to ship more betas or Community Technology Preview (CTP) versions of WinFS, and those releases will work with Windows Vista betas in addition to XP. When Windows Vista ships in late 2006, WinFS will still be in beta, but at a later time, the final release will be made available to Vista and XP users as an add-on, and probably for free. "We'll ship WinFS as we do the .NET Framework today," Rizzo added, "as an out of band update for Windows." Future versions will no doubt incorporate WinFS natively, but Rizzo declined to state whether it would ship as part of Longhorn Server, currently due in 2007.

Also, while Rizzo expects WinFS to morph into the Windows file system at some point, he doesn't see Microsoft replacing the drive letter-based system we use today with the the cleaner WinFS namespace any time soon. "Legacy application support will stop us from fully leaving the drive letter based file system behind," he told me. "However, we will likely extend WinFS in the future with a feature from SQL Server 2005 called mount points. With mount points, you will be able to mount WinFS data stores arbitrarily at any point in the file system. So we'll have mount points in the future. But we'll probably be stuck with drive letters for the next 10 to 20 years as well."