Microsoft used its annual WinHEC (Windows Hardware Engineering Conference) last week to get aggressive about 64bit computing.

The company urged hardware suppliers to start building 64bit drivers now so as to avoid any hardware incompatibilities that might slow the adoption of its forthcoming 64bit Windows.

Microsoft said it plans to deliver versions of Windows XP and Windows Server 2003 for 64bit Extended Systems in the fourth quarter.

"There's a real call to action here. Let's make sure the device drivers are not a gating factor for people who want to move to 64bit," chief software architect Bill Gates said.

Gates predicted that by the end of 2005 Intel and AMD would support 64bit in every processor.

Microsoft officials shed little light on when they hoped to ship the first solid beta of Longhorn or when the finished version of that operating system would be available. But the company did make available to conference attendees an updated developer's version of Longhorn, first introduced in October 2003.

Jim Allchin, vice president of Microsoft's platforms group, said Microsoft has more closely tied development of the server and client versions of Longhorn. But Allchin did not spell out whether this means both versions will arrive together.

Greg Sullivan, lead product manager of Windows XP at Microsoft, said there will still be "some period of time" between when the client version arrives and when the server version arrives.