Microsoft has ruled out putting Internet Explorer 9 on Windows XP, leaving millions of PCs open to Mozilla and Google browsers providing hardware-accelerated rich-internet.

Ryan Gavin, senior director of IE business and marketing, said Microsoft would not put IE9 hardware acceleration features in the current version of its browser, IE8, or back port IE9 to older PCs running Windows XP.

Gavin, speaking to The Reg as Microsoft released the first IE9 beta Wednesday, told us - twice, in fact - that Microsoft would "continue to focus on how we do a great job with Windows 7."

Translated: the future is Windows 7, and there's no going back to Windows XP. Users will instead get a "great" web experience using IE8, he said. Windows XP users just won't get the "beauty of the web" experience dreamily promised by Microsoft with IE9.

Blocking a marriage between IE9 and Windows XP is Microsoft's decision to tie Windows 7 in to the browser via hardware acceleration, and though features like Jump Lists, which make the browser "invisible" and let web sites and apps run outside the browser directly on the Windows desktop.

Gavin, a man with a curious last name, told us: "A modern web needs a modern operating system."

Hardware acceleration comes courtesy of Direct X 10, a set of Windows APIs from Microsoft used to tap the PC's GPU processing to speed browsing and rendering of graphics and video. Direct X 10 was a major update to Direct X that does not run on Windows XP unless it's been modified.

This being the year of HTML5 hype, Microsoft is tying IE9 to HTML5 to differentiate it from IE8, Chrome, and Firefox, saying hardware acceleration provides web "experiences" not possible on the web of "yesterday".

"You don't want to differentiate on HTML5 - [as a coder] I want to be able to write this mark up once and it runs across all browsers," Gavin said. "You step on top of that and say how do I do HMTL5 right, and that's where hardware acceleration comes in for graphics, images and text."

As such, Microsoft is using HTML5 and IE9 hardware acceleration to cross promote and bring web surfers to its Bing search engine.

At Wednesday's launch event, Microsoft demonstrated Bing's trademark photo landing page running a video image built using the HTML5 video tag, and the ability to zoom in and out of a still landing-page photo.

Also, demonstrated was a preview of a search function that filters images, stores sets of images in a ribbon so you don't lose them when you click on one, and that provides gentle page fades when you press the browser's forward and back navigation buttons. The forward and back function drops AJAX in favor of CSS. Microsoft plans to release a preview of the new Bing graphics features designed to work with IE9 in a month.

Tying IE9 into Direct X 10, though, leaves millions of Windows PC open to Chrome and Firefox that also provide hardware acceleration – if slightly differently. Ahead of IE9's release, Windows XP accounts for 53 per cent of operating systems, compared to 22 per cent for Windows 7.

Chrome can target these PCs because it implements the widely adopted OpenGL graphics APIs for rendering, while Mozilla's Firefox uses an intermediate layer to talk to Direct X 10's predecessors DirectX 9, which does run on Windows XP, and to OpenGL.

Jump Lists are the other way Microsoft's preventing IE9 on Windows XP. Jump Lists were introduced in Windows 7 a year ago to provide quick access to documents and that worked with IE8 to list your frequently visited web sites.

Now, Jump Lists now let you pin an icon of favorite web sites to the Windows 7 dock at the bottom of the screen and also receive news updates from that site. It's now like a website running outside of the browser. ®