Although WinFS won't ship until after Windows Vista hits store shelves, the new file system is garnering the attention of PDC 2005 attendees who want to see the capabilities that a relational file system will bring. Microsoft on Wednesday showed off a few examples of WinFS in action.

WinFS isn't a new concept at Microsoft; the company has long made what it calls "integrated storage" a top priority. The new file system was first unveiled at PDC 2003, but many assumed the effort was dead once Microsoft announced WinFS would not be included in Vista.

Instead, as previously reported by BetaNews, WinFS will be delivered out-of-band as part of the WinFX Runtime Components. The technology has also aligned with the Microsoft data stack, so it uses the same APIs as other data types thanks to ADO.NET.

WinFS takes a SQL engine and marries it with NTFS, storing metadata for all files on a system, as well as structured data such as contacts, calendars and more. Asked whether WinFS is an individual file system or simply an extension of NTFS, Mehrotra simply explained: "It's both. It's built on NTFS and it is a file system."

Because databases usually require full-time administrators, Microsoft has built what it calls the "Guardian" to monitor the WinFS store and handle page failures, tuning indices, and "things you would have needed a DBA for," Mehrotra said.

WinFS does away with file and folder hierarchy and replaces it with items and associations. Items can be standard file-backed objects such as images and documents, or objects not backed by tangle files including contacts and e-mail.

For file-backed items, WinFS leverages NTFS to store the data and ensure compatibility with current Win32 applications. When a file is changed, the system re-syncs the necessary metadata with WinFS.

Associations play an important role in establishing relationships between different types of data and allow users to organize information based how it's used. "Tagging and searching isn't enough," said Mehrotra, explaining that data needs to modeled naturally not manually.

Providing an example of how this change could be useful in the real world, Mehrotra described a situation in which a contact's information has changed. WinFS could remove the need to update numerous disparate data stores -- from a local address book to company-wise CRM application -- which can all instead utilize the storage technology.

Beyond that, WinFS also allows items to be grouped into a single, accessible product. For example, people with digital cameras often dump multiple shots of the same subject onto a PC, Mehrotra noted. WinFS would enable those users to choose one item to be representative of all the items.

Beta 1 of WinFS is available now and was distributed at the PDC. The test release works on Windows XP SP2 and Windows Server 2003, in addition to Windows Vista builds.