Watching users fumble and nearly drop an early version of the FlipStart compact PC practically gave Robin Budd a heart attack. The culprit was the three-key sequence, Control-Alt-Delete, required to log off or reboot a Windows PC.
"They would be holding the device in one hand, and they would try to get their three fingers on the keys at one time," said Budd, senior director at FlipStart Labs, a venture backed by Microsoft co-founder Paul Allen. "You can do it if you're fairly nimble with your fingers, but it's sort of a tippy, precarious thing."
When the shrunken-down laptop goes on sale later this month, early adopters might get a kick out of FlipStart's solution: a dedicated key marked "Ctrl Alt Del."
The FlipStart, like other so-called ultra-mobile PCs, may give workers tools to do more from the road. At the same time, the Control-Alt-Delete problem is a reminder to electronics makers that the human body is not keeping up with ever-shrinking gadgets.
Manufacturers have not found "the sweet spot between small enough for portability and big enough to use and interact with," said Gregg Davis, a principal at Design Central, an industrial design company in Columbus, Ohio.
The FlipStart has a laptop-esque clamshell design, so that users tired of thumb-typing can set it on a desk and peck away and still see the screen.
Another ultra-mobile PC, Sony's VAIO UX, sports a slide-out keyboard, designed to allow "standup computing" so Japanese office workers crammed into commuter trains can be productive.
An ultra-mobile made by OQO, the forthcoming model 02, has a backlit slide-out keyboard for low-light use; Samsung's own Q2 sports a split keyboard arranged on either side of its tablet-style touch screen.
Each device maker also has a different sense of how small an ultra-mobile can get before it becomes impossible to use. For instance, Microsoft thinks the tiniest screen possible measures 7 inches diagonally, but FlipStart Labs settled on 5.6 inches (14.2 centimeters).
So far, the devices are used more by certain groups of workers - real estate agents and health care workers on the go, for example - than by average consumers. Among ordinary folk, there's no clear design winner.
"Everybody seems to want something different in a little tiny PC," said James Kendrick, who consults as a geophysicist for oil companies and also avidly blogs and writes about mobile PCs.
Kendrick prefers a larger tablet-style notebook, the Fujitsu P1610. When he uses anything smaller, he carries around a fold-out portable keyboard.
Myriam Joire, a video game software developer and OQO enthusiast, says that even though her computer's tiny keyboard is not perfectly comfortable, it beats using a stylus and touch screen for writing code, which she occasionally does on her OQO model 01.
"I'm a believer that some typing's good enough," she said. Learning to use keyboard shortcuts instead of the eraser head-sized joystick and increasing font and icon sizes also made the device easier to use, she said.
Ergonomics experts point out that even a standard laptop is far from ideal. If the screen is at a comfortable position, the keyboard isn't, and vice versa.
"Right now, we fit the laptops," instead of laptops fitting us, said Waldemar Karwowski, director of the Center for Industrial Ergonomics at the University of Louisville.
For computing in general, and especially for ultra-mobile PCs, Karwowski said he's amazed the industry still uses keyboards for input. The thumb-typing necessitated by the shrunken-down keyboards is tiring and can lead to discomfort and injuries, he said.
The challenges are not limited to hardware design; ultra-mobile PCs, for the most part, run a full version of Microsoft's Windows operating system. That's a problem, said Mark Rolston, senior vice president of creative at Frog Design, a Palo Alto, California, design group whose past projects include early models of Apple Inc.'s computers.
"Windows is a fine interface for that general-purpose, desk-centric, sitting-throne-position environment," Rolston said. But mobile computing is what he calls "high context" - the device needs to perform a very specific task, based on where the user is (in the car, for example) and what she's doing (like trying to find the mall).
"Just because you can make it small doesn't mean you should," he said.
On that count, Microsoft agrees.
"If you just take Windows, the deeply immersive mouse and keyboard experience and plug it down on a 7-inch (17.5 centimeters) or 5-inch (12.5 centimeters) screen, you have some problems," said Bill Mitchell, corporate vice president of Microsoft's Mobile Platforms division.
By Microsoft standards, ultra-mobile PCs have screens that measure less than 7 inches (17.5 centimeters), weigh less than two pounds (0.9 kilograms), run a full version of Windows and have a touch screen. Mitchell said that for this category, Microsoft shifted focus away from an interface that required fine motor skills, and made it easier for someone to get the information needed while in the car or walking down the street, reports AP.
Another, more basic problem also is on his radar: People look silly trying to cram an ultra-mobile into a too-small pocket. His best solution so far dates back to his work on the Handheld PC in the late '90s.
"I just ordered fanny packs for everyone," Mitchell said. "We're probably not going to convert the world to fanny packs."