Sun Microsystems next year plans to introduce the Advanced Product Line (APL), a family of UltraSparc-based data centre servers that are being developed jointly with Fujitsu.

But the Sun-Fujitsu servers create a potential dilemma for users because of the looming 2008 arrival of other systems based on a multicore and multithreaded UltraSparc processor, codenamed Rock, that Sun is designing itself.

Plans for the APL line were announced in June 2004. The new servers will use a Fujitsu version of UltraSparc called Olympus and are due to replace Sun's existing Sun Fire systems and Fujitsu's PrimePower machines. APL originally was schedule to debut last summer, but its release was delayed until next year.

That pushes it closer to the planned release of the Rock processor, which Sun said will appear in systems in 2008. Rock will be aimed at what Sun describes as data-centric loads such as managing and analysing information used in data warehousing and data mining. The company's other multithreaded processor, called the T1 and originally codenamed Niagara, is aimed at network-centric workloads, such as Web-facing Java applications, according to Sun.

An analyst at Insight64, Nathan Brookwood, said the APL line "should be of decreasing interest for most Sun customers" because the window between its expected availability and that of Rock-based systems seems to be closing.

But it's uncertain whether systems built around Rock will be a substitute for all the processing workloads that APL will be able to handle, an analyst at Illuminata, Gordon Haff, said. "I don't think there is any guarantee that Rock is going to outperform the Fujitsu-Sparc processors across all workloads," he said. "Sun certainly hasn't said that."

In response to questions about APL and Rock, a Sun spokesperson said the company wasn't providing details until sometime in the first half of 2007.

"Sun continues to work closely with Fujitsu to develop systems based on the APL architecture," the spokesperson said. "This is an important project for Sun, and we're pleased with our progress and our partnership with Fujitsu."

At Gartner's annual data centre conference in Las Vegas three weeks ago, analyst, Paul McGuckin, advised attendees to find out more about Sun's UltraSparc product plans.

"You need to get an explanation in writing about how UltraSparc investments are going to be protected," he said.

As a group, Sun's UltraSparc-based systems face competition from rivals such as IBM, which next year is expected to release servers based on the next version of its Power chip -- the Power6. Sun also offers its own UltraSparc alternative: the Sun Fire x64 line, based on AMD's Opteron processor.

Unix administrator at The Austin American-Statesman newspaper in Texas, Tom Jones, said he hadn't heard much from his Sun sales representatives about the APL systems.

Jones said he was leaning toward using the company's Opteron-based systems running the Solaris operating system. But he was being held back by an inability to find third-party software that had been adapted to support the Sun Fire x64 machines.