Linux software has a headstart over Windows on the new 64bit Itanium processor jointly developed by Intel and Hewlett Packard, according to Intel.

A 64bit version of Linux was available at launch and is being shipped free with many of the first Itanium machines sold.

A 64bit version of Windows XP is promised for 25 October, but many potential users will wait to see how robust the new operating system is.

Intel's UK country manager, Mark Whitby, boasted that the Itanium allowed Intel to offer support for x86 code "right across the enterprise": in other words, you could run the same x86 app on any machine from the lowliest desktop to a back-office server. But he didn't say how well it would run.

In fact, the 32bit legacy code is supported by emulation circuitry that is said to run slower than the P4. To take full advantage of the Itanium, 32bit apps have to be optimised and recompiled for the new processor.

And Whitby revealed that by far the majority of the 400 applications already ported were designed originally for 64bit RISC processors running under Unix.

These Itanium ports have generally been compiled for Linux, which is effectively becoming a new unifying Unix standard. However, many are applications written specifically for the companies that use them.

Windows is likely to overtake Linux when the range of Itanium applications begins to broaden.

"I think porting of 32bit applications will probably accelerate now," Whitby said.

He was speaking at the launch of two Itanium-based machines from Fijutsu-Siemens Computers (FSC): the Primergy N4000 four-way server, and the Celsius 880 two-processor workstation.

Prices will depend even more than usual on configuration because of the large address space.

"The RAM can cost more than the rest of the machine put together," said Bjorn Fehrm, FSC executive director of business solutions.

This ability to handle large memory will be a big driver of initial sales - often for use with massive databases. But Oracle will not offer a 64bit version of its dominant high-end database until the next iteration of Itanium, codenamed MacKinley, is launched next year.

By that time 64bit XP will have been fairly well "run in", doubtless with the issue of service releases to patch up the cracks, and take-up of the new chip is expected to accelerate.

Another big driver of initial sales, FSC reckons, will be the Itanium's support for encryption algorithms used in ecommerce.

At the workstation level Itanium will be thrown at simulations, electronic and mechanical design, complex financial what-if projections, visualisations and digital content creation.

Many of these tasks will be done under Windows because the software is not available on Linux - though, says Fehrm, most leading CAD software developers have Linux versions of their software in labs.

The 64bit architecture will go mainstream with an entry-level Itanium to be launched after MacKinley. But Intel's roadmap has the 32bit Intel dynasty continuing for at least another five years.