The lacklustre reception of the ultramobile PC hasn't put Microsoft off the portable PC space. In fact, the company has continued to work on another mini-Tablet PC concept called the Haiku, and expects it on the market within the next few years.

"We'd like to see them out in the $500 to $700 range [about £270 to £380]. The closer to $500 the better," said Otto Berkes, general manager of Microsoft's Ultra-Mobile PC operations, on the sidelines of a conference in Taipei today.

The Haiku device he showed off at the Via Technology Forum was essentially a display screen about the size of a paperback book. The idea is to use screen input methods to work the device, which would include a version of Microsoft's OS (operating system) for Tablet PCs.

The original Haiku device was shown off by Microsoft chairman Bill Gates during WinHEC (Windows Hardware Engineering Conference) last year. At the time, the company projected it might ship in 2007.

But this year's launch of the ultramobile PC, code-named Origami, prompted speculation that Origami was the portable PC of choice for Microsoft, and that it might drop other such projects. That's not the case, according to Berkes.

"We don't think [the Haiku] is feasible today, but we're very excited about the roadmap [Via] shared that will make this possible in a few years," he said.

Via competes with Intel and AMD in the microprocessor business, and in recent years has focused more on chips for portable devices. With these companies developing ever-smaller chips that run cooler, use less power and require less space inside gadgets, developing portable devices such as the Haiku becomes more feasible, Berkes said.

Microsoft delved into developing portable PC concept designs in 2002. The first device from the initiative was known as Go, and had a 4.5in display. The company continues to research the segment to find a specification that piques user interest.

The idea is to make sure that any portable PC from Berkes' division provides a full PC experience for users, and doesn't limit a user to simply playing games or watching movies on a small screen.

One of the design challenges is to make sure users have enough screen space so they don't have to squint their eyes to watch a movie or when using programs such as those in the Microsoft Office suite. Using such applications on screens smaller than 7in causes problems, both technical issues in the way the software operates and for user experience, Berkes said. Still, the company remains committed.

"We're very excited about the prospect of this kind of product moving forward over the next few years," he said.