Key Microsoft partners such as chipmakers and PC manufacturers, though, were unperturbed by the changes in software that won't arrive in final release until 2006 at the earliest.
Microsoft announced aon Friday, in order to meet that 2006 deadline for the updated operating system.
The software maker now plans only a beta release for WinFS, a major feature indented to dramatically ease information retrieval. In contrast, the new Avalon graphical interface and Indigo Web services communications technologies will appear not just in Longhorn but also be released as upgrades to the existing Windows XP.
"The exciting part of Longhorn was having WinFS and Avalon together so you could build a new kind of application. Having an intermediate Windows release will probably slow that down, which is disappointing," said Mike Sax, president of Sax Software, which sells developer tools.
Microsoft's shift will have an effect on developers in that some parts of the new Windows technology are likely to be adopted sooner than expected, analysts said. But as with PC makers, the effect won't be dramatic, because the product was still remote, Jupiter analyst Michael Gartenberg said.
"At this point it's all very theoretical," Gartenberg said. "Longhorn was an extremely ambitious project from day one. It's not the first time Microsoft has announced feature sets for an operating system and in the end had to scale back their plans a little bit."
The schedule changes acknowledge the realities of buyers' habits when it comes to operating systems, said Trent Oster, a project director at BioWare, a video game maker. "That's recognizing that a lot of people aren't upgrading Windows as much as they used to," he said.
Modernizing Windows isn't an abstract issue for Microsoft, despite its continuing dominance in desktop operating systems. Windows is a major revenue source for the company, and backers of the Linux operating system have begun to wrestle with.
Breaking out Avalon and Indigo into XP upgrades will mean those technologies will be likely adopted sooner. That piecemeal approach to release of the features was praised by Scott Hanselman, chief architect at software company Corillian. "We're seeing a change in Microsoft philosophy--it's not pave over and start again, like it was maybe in the past," he said.
Tim Huckaby, CEO of Interknowlogy, a consulting firm and Microsoft partner, said the staggered release could bring benefits to developers. "They had this one giant, completely new operating system. Now, they're making it a little more modular, which makes it easier--almost like a phased approach," he said.
However, to get the various Longhorn components onto computers, Microsoft will have to send out one large Windows update for WinFS and another for the versions of Avalon and Indigo that will run on Windows XP and Windows Server 2003.
That gradual delivery process could make it harder for programmers to know what Windows infrastructure they should target their work toward. "The thing to be afraid of is that it will be confusing for users to know whether they have the software to run an application, because there will be so many parts," Sax said.
Microsoft has not yet decided how it will release the software updates, said John Montgomery, director of marketing for Microsoft's .Net Framework product division. However, the company is considering using existing mechanisms for shipping out new software, including automatic updates and service pack deliveries, he said.
Little effect for PC makers
Dell and Gateway said that the changes in Microsoft's software schedules won't have much of an impact on their overall plans. Just as before, they said they plan to offer Longhorn when it becomes available.
"Microsoft is a valued partner, and we look forward to delivering the added features and benefits of Longhorn to our customers," said Jim Totten, vice president of software at Dell.
While Intel's marketing plans do involve Microsoft technology, Longhorn is still too far in the future for the changes to require any shift in the chipmaker's plans, said spokesman Howard High. "I can't believe we've got a lot locked down or invested at this point," he said.
IBM and HP declined to comment on Friday.
Reactions from Microsoft's competitors were less neutral. Novell, which sells SuSE Linux, licked its chops over Friday's news. "The delay of WinFS will give Novell a longer window to push its own, Simias and other related technologies to the public," said Miguel de Icaza, chief technology officer at Novell Ximian Services.
And Red Hat was eager to point out it has "tremendous demand" for its desktop version of Linux, with several thousand of users involved in pilot projects, spokeswoman Leigh Day said.
Part of the reason that Microsoft had to delay WinFS has to do with the company's decentralized structure, Forrester analyst John Rymer noted. Different teams within Microsoft are contributing technology to Longhorn; Microsoft's SQL Server database group is behind the design of WinFS.
"It seems that the underlying fact of the matter is that their ambition outstripped their management--their organizational structure could not support what wanted to do," Rymer said.
In the long run, Microsoft is correct to give security and stability a higher priority than timeliness, one Microsoft partner said.
"WinFS is going to be great, but how business-critical is it?" said Kerry Gerontianos, president of Incremax Technologies, a reseller and Microsoft partner. "I'd love to see WinFS, but I'd rather make sure customers are happy first and feel secure."