The first virus to attack handheld computers running Microsoft's Windows Pocket PC software has been found.
The Windows software runs on some handheld computers
It is called "Duts", and its existence has been revealed by the Romanian security firm BitDefender.
The company said the virus posed no threat and was produced only as a
"proof of concept" by its creators.
The program comes from the same virus writing group that put together similar code that could spread between smartphones running Symbian software.
BitDefender said Duts had been created by someone calling themselves Ratter, who was part of the 29A VX virus writing group.
In a statement, the company said it had written the code to show that it was possible to create programs that could spread via handhelds and mobile devices running the cut-down version of Windows.
BitDefender estimated that there were about 17 million Windows Pocket PC devices in use around the world.
The company said: "The code was first sent to anti-virus experts instead of being released in the wild."
The virus has been written to be polite as it asks permission to spread to a new host when infected applications are being run.
"You're more likely to have a meteorite strike your house than be hit by this virus," said Carole Theriault, anti-virus consultant for Sophos.
"Owners of PDAs running the Pocket PC operating system should not lose any sleep over this virus, although it might be a taste of things to come in the future."
The virus is named after a technology called Dust dreamed up by science-fiction writer Greg Egan in his novel Permutation City.
However, the privilege of naming viruses rests with the anti-virus firms, which have decided to call it Duts.
Last month, the 29A group released another proof-of-concept virus called Cabir that was aimed at devices using the Symbian operating system.
Phones vulnerable to this virus include Nokia's 3650, 7650 and the N-Gage gaming/mobile hybrid.
The Cabir virus uses the Bluetooth short-range radio system to spread between devices and disguises itself as a security program. It also asks permission to install itself.
Any device running the Symbian's Series 60 software could be vulnerable but anti-virus firms say there is little evidence that the virus is spreading in the wild.