Torvalds isn't nuts - he just has a passion for kernels...

In his book, Just for Fun - which hit the shelves yesterday and can be ordered at http://www.silicon.com/linusweek for a 10 per cent discount - Torvalds brands the OS X kernel a "piece of crap".

He says Apple was forced to release the operating system prematurely in order to fulfil promises made to customers and shareholders earlier last year, and is therefore not ready for use.

But in the interview with silcon.com, Torvalds said that the reason he rounded on Apple is because he is passionate about the design of operating systems' kernels.

"I am opinionated, especially when it comes to kernels, because that's what I have been doing for the past ten years. Mac's kernel tries to have these lofty ideals and I think these ideas are wrong. The ideals have also led to some bad decisions inside the kernel," he said.

Microsoft, an open source opponent, is renowned for regularly releasing unfinished products in a blaze of marketing hype. Despite his condemnation of the premature OS X release, Torvalds stopped short of accusing Apple of employing the same tactics. He suggested, rather, that Apple had no alternative on this occasion as the OS was already delayed.

"I think OS X was probably unfinished but& they wanted to release it," he said. "However, I do think they were very honest about it and told everyone it wasn't perfect."

Simon Moores, chairman of the Research Group, agreed with Torvalds, claiming the software giants are unconcerned whether the software is ready or not on its release.

"Most of these companies are driven by their quarterly targets, not by the users' interests or the practicality of the software itself," he said.

Apple declined to comment.