Sun will announce plans to launch a second, thin client version of its Mad Hatter Linux desktop at its Sun Network Conference in San Francisco this week.

At the firm's nearby headquarters, Josef Edlinger, manager of engineering and technology for Sun's iForce partner centre, demonstrated the potential benefits of combining the new desktop with its existing Sun Ray thin client appliance.

Mad Hatter is a low-cost competitor to Microsoft Windows, and includes Sun StarOffice word processing and spreadsheet, the Gnome graphical user interface and Novell's Ximian Evolution email and calendaring on top of Red Hat Linux.

The 'fat client' version of Mad Hatter is expected by the end of the year, and Edlinger estimated the low bandwidth version would appear in the second quarter of 2004.

The thin client version Mad Hatter is designed to work remotely over a wide area network. But this has data transfer performance issues, prompting the company to work on improving compression algorithms to achieve a 370Kbps transfer rate.

Sun is now trialling Mad Hatter running on Sun Ray with 100 staff at their homes.

"We are getting very positive feedback and there are of course no virus problems," said Edlinger.

And 370kbps was near the lower end of broadband bandwidth connection capabilities so gave satisfactory performance, he added.

The Sun Ray appliance, which Edlinger said saved about 30 per cent per seat over a standard desktop, has no moving parts but includes a Java card reader.

A user inserts their personal Java card at any appliance to bring up their personalised desktop. Removal of the card immediately blanks the screen, and data is not held locally on the appliance.

A standard desktop with added Java card reader can operate in the same way. Edlinger added that Sun was also looking at a consumer version of the technology.

"We will probably bring it out [in conjunction] with a telco to include internet connection and email along with Java card access," he said.