The next version of Windows will include a new document format, code-named "Metro," to print and share documents, Microsoft said Monday. Metro appears to rival Adobe Systems's PostScript and PDF (portable document format) technologies.

Metro was demonstrated during Microsoft Chairman and Chief Software Architect Bill Gates' keynote at the start of the Windows Hardware Engineering Conference (WinHEC) on Monday in Seattle.

The format, based on XML (extensible markup language), will be licensed royalty free and users will be able to open Metro files without a special client. In the demonstration, a Metro file was opened and printed from Internet Explorer, Microsoft's Web browser.

Printers and printer drivers can include support for Metro and deliver better and faster printing results than with today's printing technology, Microsoft said. On stage, a Xerox Corp. printer with Metro built in was used to print a sample slide.

The Metro technology is likely to go head-to-head with Adobe's PostScript technology. "It is a potential Adobe killer," said Richard Doherty, research director with The Envisioneering Group in Seaford, New York. "But this is just the first warning shot. Adobe could put something that is even more compelling [on top of] Longhorn."

Aside from the first showing of Metro, Gates on Monday ushered in what he called the third decade of Windows computing with the release of 64-bit versions of Windows and talked up the next Windows release, code-named Longhorn, due late next year.

Gates announced general availability of Windows XP Professional x64 Edition and three 64-bit server operating systems: Windows Server 2003 Standard x64 Edition, Microsoft Windows Server 2003 Enterprise x64 Edition, and Microsoft Windows Server 2003 Datacenter x64 Edition.

The 64-bit operating systems offer users greater computing power as systems can process more data per clock cycle and can use larger amounts of memory.

The transition to 64 bits will be quick and smooth, Gates said. This is particularly true on the server, where immediate benefits with support for more Terminal Server sessions and the greater performance for Active Directory will appeal to enterprise users, he said. 64-bit hardware will be mainstream on servers by the end of the year, Gates said.

On the PC, it will take a year before 64-bit hardware is mainstream, Gates predicted. The software transition will be slower because of a lack of applications and drivers. Also, the need to test applications might hold back 64-bit adoption and so Microsoft will also ship a 32-bit version of Longhorn.

Gates also offered a sneak preview of Longhorn, calling on Microsoft employees to demonstrate search and indexing features of the Windows XP successor. Microsoft is building desktop search features into Longhorn and retiring the current search feature in Windows XP.

WinHEC attendees will receive a preview version of Longhorn, intended for hardware makers to develop drivers for the operating system. A first Longhorn beta is due by the end of June and the final version in late 2006, but any date could slip because of issues that may come up during testing, Gates said.

Gates repeated that Longhorn will be a big deal for Microsoft and that it will be pushed into the market by the company's biggest marketing effort yet.

WinHEC runs through Wednesday.