It's only supposed to happen with a sports car or diamond ring. But the employees at San Francisco's OQO can't take their company's sleek new computer out in public without drawing attention. On airplanes, buses and trains, curious onlookers relentlessly ask about the thin, ceramic-colored device that fits snugly in your hands and weighs a slight 14 ounces. Everyone wants to talk about it, play with it and usually find out where and when they can buy their own. Even the guards at SFO, apparently plugged into wild Internet rumors about new gadgets, asked about the device when CEO Jory Bell passed through security recently. "They wanted to know if it was a new Apple PDA," Bell says.

It isn't. Next month, the three-year-old, 42-employee start-up will unveil the OQO Model 01, the first in a new breed of portable computer that the high-tech industry has dubbed "ultra-PCs." Think of them as a mixed breed--with pedigree: it looks like a PDA but operates like a laptop and runs the full-featured Windows XP operating system, not the watered-down version found on Pocket PCs. The OQO, which will sell for $1,899 only on the company's Web site, has a five-inch-wide screen that slides out to reveal a small keyboard, and many of the ports and plugs you find on the back of your desktop.

The ultra-PC is a holy grail of sorts in the tech world: corporate IT managers will no longer have to arm their mobile workers with PDAs running special diluted versions of the company's software. And since the OQO is so compact, business travelers can now log on using the OQO's wireless Internet capabilities in tight spots like airplanes and cafes. "You can use it in places where you would not think to use a PC, or physically cannot use one," says Bell.

The computer industry has been trying to perfect the ultra-PC for a decade. Big companies like IBM and Sony initially had trouble finding a processor that was inexpensive and powerful enough but would not overheat a pocketable device. "Every major company looked at the concept and fundamentally determined it was not feasible," says Tim Bajarin of technology consultant Creative Strategies.

Founded by veterans of Apple and IBM, OQO exploited three innovations to make its device work. Semiconductor upstart Transmeta, an Intel rival based in Santa Clara, Calif., finally rolled out a high-powered, low-heat chip called the Crusoe in 2000. More recently, surging sales of Apple's iPod music player drove down the cost and increased production of Toshiba's 20-gigabyte hard drive, which OQO also uses. Finally, OQO's engineers provided the secret sauce--re-engineering the PC from the ground up to save space and further reduce heat output. A key advance: many of the features controlled by microchips in conventional computers, such as the keyboard, backlight and clock, are now managed by software in the OQO.

Though it's first out of the gate with its ultra-PC, OQO won't have the stage to itself for very long. Microsoft cofounder Paul Allen's Vulcan Ventures has a similar device, called the FlipStart, set to debut next year. A Colorado start-up called Antelope Technologies is selling an early IBM design, a pocketable, screenless computer that runs Windows and plugs into keyboards, displays and power supplies. Bajarin says giants like Dell, HP and the Asian computer makers will jump in once companies like OQO prove there is a vibrant market.

None of this worries CEO Bell. He says today's PC firms outsource so much of their design and manufacturing to Asia that they will be slow to successfully engineer an ultra-PC. He also has that other reason for optimism: everywhere he goes, people want to play with his computer.