Microsoft has scrapped the WinFS (Windows Future Storage) file system as a separate component, according to Quentin Clark, Microsoft's director of programme management for WinFS.

The decision means that a decade after after Microsoft began developing a file system aimed at bringing relational database concepts to Windows, the operating system is unlikely to get that technology after all. Instead, Clark said, different aspects of WinFS will be parcelled out to various products, just as Windows Vista's search capabilities draw on technology originally planned as part of WinFS.

"We will continue working the innovations, and as things mature they will find their way into the right product experiences - Windows and otherwise," Clark wrote in a blog post on Friday.

Microsoft has been working on the predecessors of WinFS for a decade, and most recently WinFS was billed as one of the three main technological advances to be built into Windows Vista, along with its graphics display system and communications system. Microsoft said in 2004 that Vista wouldn't ship with WinFS after all, but planned to release the file system as an add-on.

The company has shipped an initial beta of WinFS, and planned a second test version for later this year. Beta 2 has now been scrapped, Clark said.

"We are not pursuing a separate delivery of WinFS, including the previously planned Beta 2 release," he wrote. "With most of our effort now working towards productising mature aspects of the WinFS project into SQL and ADO.NET, we do not need to deliver a separate WinFS offering."

One aspect of WinFS, a relational model organised around Entities, is being built into ADO.NET, the upcoming version of ActiveX Data Objects, Clark said. The next release of Microsoft SQL Server, code-named Katmai, will get WinFS' unstructured data support and automatic administration technology. Katmai is expected to appear in two or three years.

Clark played up this news, despite the fact that it is far less ambitious than the "universal storage" Bill Gates has long personally championed. "This really is a big deal – productising these innovations into the mainline data products makes a big contribution toward the Data Platform Vision we have been talking about," Clark wrote.

He said customers have often requested WinFS technologies to be more broadly available in data platform products.

Microsoft last week released a white paper discussing the upcoming ADO.NET Entity Framework.

Readers of Clark's blog post expressed dismay that WinFS appears to have vanished from Windows for the forseeable future.

"Everything sounds so rosy in the article with all the progress on the technologies, (and) yet there will be no SQL file store for Windows. So that's it then... WinFS is dead," wrote one reader.

"The bottom line is that WinFS was promoted as a Windows component that would enhance the file system and provide a new platform for data storage for Windows apps. And this is now dead. No amount of spin is going to cover that up," wrote another.

The decision to change direction on WinFS is not entirely a surprise, and the timing of the decision just after Gates' announcement he will step down as chief software architect may not be a coincidence.

Two weeks ago, in an interview with CNET News.com, Gates said he was pushing his successor, Ray Ozzie, to "carry the torch" on WinFS and unified storage. In another interview the same week, Bob Muglia, who heads Microsoft's Server and Tools business, expressed doubt about WinFS in the operating system, but said Microsoft was still planning a second beta release.