A first beta release of the next version of Windows is likely to be delayed until next year because Microsoft is concentrating first on a security-focused update to Windows XP.
Microsoft had said it would deliver a beta version of Longhorn by the middle of the year. However, the test version is now expected in early 2005 because many developers working on Longhorn have been reassigned to work on Service Pack 2 (SP2) for Windows XP.
"Based on what has happened over the past year in the area of security, we took a look at what was going on with Windows... and pulled resources from Longhorn development in order to deliver Windows XP Service Pack 2. That slightly impacted the beta schedule for Longhorn," said Greg Sullivan, lead product manager for Windows at Microsoft.
Windows XP SP2, scheduled for release in the first half of this year, is more than the usual roll-up of bug fixes and updates.
Microsoft is using the update to make significant changes to Windows that are designed to improve security in four main areas: network protection, memory protection, e-mail and web browsing.
Longhorn is a major Windows release, a "big bet" for Microsoft, chairman and chief software architect Bill Gates said last year. Gates has described Longhorn as a "big breakthrough release" and the most significant release of Windows since Windows 95.
Microsoft released a special preview version of the software at its Professional Developers Conference last October. An updated developer preview will be distributed at the Windows Hardware Engineering Conference (WinHEC) in Seattle next month.
Although pulling developers off Longhorn to work on Windows XP SP2 affected the Longhorn beta release, the long-term effects are negligible, Sullivan said.
"We're coming down the home stretch in delivering SP2 and some of those [reassigned] resources have already begun to go back to focus on Longhorn. I don't think the long-term impact is too significant," he said.
Microsoft had set 2005 as the release year for Longhorn, but has since backed away from that commitment.
Gates earlier this week said Longhorn is "not a date driven release", adding that speculation that the operating system will come out in 2006 is "probably valid speculation".
Last month the company also pushed back the release date for major upgrades to its database and developer tools to the first half of 2005, a delay of as much as six months. Yukon, the codename for Microsoft's SQL Server 2005 database, and Whidbey, the code name for Visual Studio 2005, both had been due in the second half of 2004.
Given the recent schedule slips, even 2006 is a tough target to hit for Longhorn, said Jupiter research senior analyst Joe Wilcox.
"I don't see how serious Longhorn work can start until Microsoft releases Yukon and Whidbey. So, assuming the first Longhorn beta is ready around the time those products ship, 2006 is tough," he said.
Longhorn promises to give users a secure operating system with a new way to store files, revamped graphics and tight links to the web.
The operating system is built up of three components that sit on top of a layer of "fundamentals" that includes security and technology to make sure applications and drivers do not conflict.
On top of those fundamentals sit Avalon, WinFS and Indigo, codenames for a presentation subsystem, unified storage system and communication technologies, respectively.
Before Microsoft delivers Longhorn, the company is expected to make another marketing push for Windows XP. A plan is being drafted under the project name Windows XP Reloaded.
Joris Evers writes for IDG News Service