Sun has explained more of the strategy behind the Advanced Product Line (APL) family of processors, which it is jointly developing with Fujitsu.

The two companies announced on 1 June that they would merge development of their Sparc processors, resulting in the APL by 2006.

Combining development with Fujitsu frees up some of Sun's investment budget, allowing the company to speed up development of a next-generation technology that it refers to as a 'system on a chip'.

"The natural kind of life cycle for the APL product line would be three years," said Andy Ingram, vice president of marketing for Sun's scalable systems group.

As yet there are no plans to continue the cooperation beyond that.

The system on a chip is currently being developed for the chips codenamed 'Rock' and 'Niagara 2'. Both are expected to be available by 2008, making them the perfect replacement for APL.

Sun predicts that the new design will deliver a tenfold speed increase while significantly reducing the size of the server box bought by the customer.

Ingram described the development of APL as a conservative safe bet, while the system on a chip technology offered a "higher risk and potentially higher rewards".

The joint development deal does not include the development efforts that Sun is putting into Rock and Niagara 2.