Sharp has launched its Zaurus SL-5500, the first commercially available Linux-based PDA.

The device is built around a StrongARM 206MHz processor with 64Mb of SDRam, 16Mb of Flash Rom and expansion slots for both Compact Flash and Secure Digital cards.

An unusual addition is support for both stylus input and a small thumb-operated keyboard.

Sharp has used Lineo's Embedix Linux 2.4 kernel as the operating system for the device. Swedish developer Trolltech's Qtopia Palmtop Environment provides the graphical user interface.

The Zaurus software bundle includes the Opera web browser and Hancom's Mobile Office productivity suite, which supports documents in Microsoft Office format.

Daniel Wan, product marketing manager at Sharp, said that Linux makes the most of the Zaurus hardware capabilities, and provides an open platform for future development.

He claimed that it also differentiates the device from other PDAs on the market. "It would have been easy to launch another PocketPC device, but this would have been a 'me too' product," he said.

Ease of development is another consideration. "There's a ready-made force of Linux and Java programmers. This makes the learning curve for application development smaller than for Palm or Pocket PC," he explained.

Sharp has also launched its MyZaurus.com portal as a focal point for new applications.

Trolltech's Eivind Thoronsen said that the portal is helping to create a community around the device. The company will also offer a commercial testing kit for Qtopia-compatible applications.

Thoronsen claimed that the kit will be "well priced for single developers as well as organisations".

Mark Klein, product manager for PDAs at Sharp, believes that the Zaurus will appeal to both consumers and enterprise users.

Versions of both MySAP and Sybase iAnywhere have been developed for the device, and Klein expects other similar developments in the future.

He also sees Linux's strong networking support as a benefit in the enterprise. Bluetooth support will be added to the Zaurus in mid-2002, and Wi-Fi cards are already available for the device.

The SL-5500 will be on sale from May for £370 ex VAT through Sharp's online store, retail outlets and resellers.