At the annual gathering, system and device vendors as well as a number of ISVs will look for the latest skinny on the various Windows platforms, including 64-bit support and, according to sources, a new mini Tablet/eBook hybrid form factor.

While Microsoft Corp. will play up the show as a coming-out party for its 64-bit Windows releases, there also should be lots of new Longhorn client and server product information, as well.

In a road tour across the country this month, Jim Allchin, the group vice president of Microsoft Platforms, advanced the WinHEC message that Longhorn will be more than just Windows XP Service Pack 3 for customers and developers.

For example, Microsoft recently confirmed that it will deliver to attendees the first Longhorn desktop preview build during the WinHEC confab. This build will be tailored for hardware and software makers focused on building new drivers for Longhorn. The company also is on tap to share its Longhorn system requirements and an updated timeline for its next-generation Windows releases.

Click here to read about Longhorn's "Palladium" security, details of which are due to be released at WinHEC.

Microsoft recently shared details about some of its plans for networking in Longhorn. According to the WinHEC agenda, company brass will share more about changes Microsoft is making to Windows' power management facility; the WinSAT performance-test tools that will be built into Longhorn; and a subsystem known as WHEA (Windows Hardware Error Architecture) that will be built into Longhorn.

Storage is set to be a key WinHEC theme, as well. According to the show agenda, Microsoft and its partners will discuss "hybrid" hard drive futures, including support for the non-volatile Flash memory cache that Microsoft is building into Longhorn.

Less than a month ago, Microsoft released final code for its Windows XP Professional x64 client and Windows Server 2003 x64 Edition server to manufacturing. The rollout will be accompanied by 64-bit announcements from OEM processor manufacturers and server, desktop and peripheral device vendors.

To read more about the future of 64-bit computing, click here.

Finally, the company may show hardware developers a prototype of a new device—described by sources as a type of hybrid Tablet PC/eBook—that has reportedly been making its way around the Redmond campus. The mini-Tablet, which is said to measure about 6 by 8 inches and feature a digitizer, is just one of a number of new Tablet form factors expected to debut in the coming months.

Microsoft hasn't outright denied the existence of such a device.

"Microsoft's OEM partners are working on a variety of form factors exploring the complete mobile experience," said a Tablet PC spokesman to Microsoft Watch earlier this month. He then declined to say anything further about the alleged device.

WinHEC 2005 is slated for April 25-27 at the Washington State Convention Center in Seattle.

This article was originally published on eWEEK.com.