Over the past few years, advocates of the Linux operating system have mounted several failed offensives to try and conquer the desktop, but at the same time a less visible battle has been going on in the PDA (personal digital assistant) market. The difference between them? Linux may actually have a chance on PDAs.

Several personal organisers running Linux were on display at this year's Comdex IT trade show in Las Vegas, including Sharp's upcoming Zaurus, which will be the Japanese electronics giant's first PDA released in the US to ship with the operating system installed. South Korea's Gmate, meanwhile, showed its Yopy device, while a German company launched a version of Linux designed to run on Compaq's iPaq.

The battle for acceptance on PDAs depends in large part on having a graphical user interface (GUI) that's acceptable to users. Sharp's Zarus SL-5000, which is expected to launch early next year, will use the Qt interface from Trolltech.

"The market is now starting to accept Linux and, having Sharp on board, they feel comfortable," said Aron Kozak, Trolltech's product marketing manager for Qt. The first versions of the Zaurus, which are being made available to developers this month, will be priced at around £280 plus VAT.

Linux has a couple of factors in its favour on PDAs, according to its advocates. "Linux is at least as powerful as [Microsoft's] Pocket PC," Kozak said. "It's also completely scalable — you can shrink it down to nothing."

The Zaurus (pictured) is based on Intel's StrongARM 206MHz processor, the same chip used in Compaq's iPaq and HP's Jornada, both of which run Microsoft's Pocket PC software.

The Sharp deal was inked after a developer at the Japanese firm downloaded Trolltech's software onto an iPaq he was using and decided he liked it.

Interest in downloading Linux for iPaqs is eclipsing handheld computers that are sold with Linux preinstalled, according to one analyst. "Although there are probably less than one percent of iPaqs that are running Linux, it's probably talked about as much as all the other [Linux PDAs] combined," said Todd Kort, a principal analyst with Gartner.

Tuxia, a German company that makes an embedded version of Linux, launched a downloadable version of the OS for iPaqs at Comdex last week.

Publicity that the company garnered resulted in between 300 and 400 versions of the software being downloaded in a day, said Anthony O'Sullivan, Tuxia's vice president of marketing. "Up to then, we had about 150 downloads total," he said.

But he acknowledged what some see as a significant stumbling block for Linux on PDAs, which was also a factor that hampered the operating system's acceptance on the desktop: the availability of compatible applications.