SEATTLE — While this year's Windows Hardware Engineering Conference (WinHEC) here this year will be heavily focused on 64-bit processing, it also will serve as a showcase for new kinds of smaller, portable laptop and Tablet PC devices.

Microsoft chairman Bill Gates, who is slated to deliver the Monday morning kick-off keynote address for the show — which is expected to be attended by 2,800-plus hardware and software developers — will show off three new "inherently mobile and connected" small form-factor devices, company officials said.

In addition, on Tuesday, Bill Mitchell, Microsoft Vice President of Mobile Platforms, is on the docket to discuss "Trends and Opportunities for Tomorrow's Mobile PC" at WinHEC.

Today, Gates is scheduled to show off a new Acer Inc. "ultra-portable laptop convertible"; an ASUS Computer International laptop featuring an auxiliary display; and a hybrid mini-Tablet PC/eBook combination device that is still in prototype phase, officials said.

The Acer and ASUS machines are meant to showcase Longhorn, the next version of Windows, which is due to ship in 2006. The hybrid mini-Tablet PC/eBook system is a "post-Longhorn" device, according to Greg Sullivan, lead product manager for Microsoft's Windows client team.

Gates will use the Acer machine to show off how the improved "instant-on" technology in Longhorn will work, Sullivan said. By taking advantage of newly supported hybrid flash/magnetic disk drives, Longhorn will be able to boot up more quickly, as well as consume less battery power, Sullivan said.

Gates will demonstrate how auxiliary displays — a new type of graphics display technology — could work by demonstrating the ASUS laptop prototype.

But the likely star of the small form-factor show at WinHEC will be a new hybrid Tablet/eBook device that has been making the demonstration rounds on Microsoft's Redmond campus as of late.

The hybrid device, which won't be available until sometime in the "post-Longhorn" timeframe, will measure 9-inches diagonally, weigh between one to two pounds; feature an all-day-life battery; and run a full Tablet version of the Longhorn operating system, Microsoft officials said. The systems also will include Microsoft Reader and ClearType, allowing them to function not just as Tablets, but also as eBook systems.

Microsoft is describing this system, code-named "Haiku," as an "ultra-mobile PC." Microsoft is working to find OEMs to build these new devices and sell them for between $500 and $800 U.S., making them ideal for the academic market, among others.

The prototype of this device that Microsoft will demo at WinHEC will be a "reference design" developed by several OEMs in collaboration, Sullivan said.

Microsoft introduced the Tablet PC concept in 2000. The first units running the Tablet-PC-specific variant of Windows XP began shipping in 2002. According to Microsoft, the millionth Tablet PC was sold in February, 2005.

Microsoft has been criticized, by even some of its closest Tablet allies, for trumpeting the Tablet's arrival, but then failing to follow through with adequate marketing. Some said Microsoft has been compounding the problem by delivering conflicting messages about the future of the Tablet operating system. Recently, Microsoft and its partners have been playing up Tablet PC systems that double as convertible laptops, rather than the original slate-form-factor models.