Apple at its annual World Wide Developers Conference has lashed out against Microsoft for copying its OS X 10.4, codenamed Tiger, in the forthcoming Windows Vista operating system.

"Our friends up north spend $5bn a year on research and development," Apple chief executive Steve Jobs said in a reference to Microsoft.

"And yet these days all they seem to be able to do is try and copy Google and Apple. So I guess it’s a good example of how money isn't everything."

Apple's senior vice president of software engineering Bertrand Serlet pointed to the desktop search technology built into Windows Vista and compared it to the Searchlight light feature in OS X 10.4 Tiger.

"We have this incredible technology under the hood," Serlet told delegates. "After the WinFS debacle, [Microsoft has] been scrambling to understand how to integrate that stuff."

WinFS was scheduled to provide a new file system for Windows. It would make searching for items much easier because instead of files, it sees data items such as email messages and photos. Microsoft last June axed the technology from Windows Vista.

Serlet further argued that Microsoft mimicked Apple by integrating an RSS reader into its web browser. He also raised questions about Microsoft's decision to unbundle Outlook into separate applications for calendaring and email. Apple always has had separate applications for those tasks.

Turning the knife on Microsoft's forthcoming operating system, Serlet then turned his attention to the new Windows logo that replaced the start button in the bottom left. It features a Windows Logo placed inside a blue sphere.

Referring to the Aqua user interface in OS X, he described the Windows Vista logo as a "standard Windows logo with a nice aqua bubble on top".

"But you know, underneath it all it's still Windows."

The Windows Vista mockery was intended as a joke.

Later at the WWDC event, Apple showed off several new features of the forthcoming version of its OS X 10.5 operating system, codenamed Leopard.

Among other things, it will feature a technology dubbed Time Machine. This lets users recover documents that they deleted in the past or allows them to restore a file to a previous version when the user has accidentally overwritten a document.

Microsoft plans to offer a similar technology called Previous Versions.

Apple itself is also no stranger to copying software features that were pioneered by others. Microsoft was the first to publicly show off desktop search in 2003 and the technology was first delivered by Google with its Desktop Search product.

Although it is subject to debate, many have argued that the idea behind Apple's Dashboard of creating a platform to run small JavaScript applications was pioneered by Konfabulator in 2003. The company has since been acquired by Yahoo.