Microsoft has pleaded with hardware makers to develop 64-bit device drivers to fit its upcoming 64-bit Windows releases. Otherwise, said Microsoft boss Bill Gates at WinHEC in Seattle, it could slow the uptake of Microsoft's 64-bit products. "There's a real call to action from us here. Let's make sure the device drivers are not a gating factor for people moving to 64-bit," Gates said.

However, both Microsoft and chip maker AMD said they didn't think there would be a major problem developing drivers for a brand new computing model, despite previous experience suggesting that major architectural changes such as this are rarely - if ever - as smooth as vendors predict.

Microsoft announced at WinHEC that it will deliver 64-bit versions of Windows XP and Windows Server 2003 in the fourth quarter of 2004. Previously, the company had only said it would ship the software in the second half of the year, although Microsoft OS release schedules have so far proven to be guidelines at best.

Makers of hardware such as network interface cards, modems, graphics cards, printers and scanners have to develop 64-bit drivers for their products to work with the operating systems, Microsoft said.

Despite the considerable amount of work that device driver makers have still to do, Microsoft doesn't foresee any major problems when its 64-bit operating systems are released. "It is really not any different than, for example, when we moved from a 16-bit DOS environment to a 32-bit Windows environment. It is not an industry showstopper, but it is definitely a monumental challenge," Phillips said. What Phillips didn't remind his audience of was the considerable software industry shake-out that occurred during that move from 16 to 32-bit computing, and the compatibility issues faced by users.

Processor maker AMD isn't worried about device driver trouble either, although some peripherals initially may not work, said Tim Wright, AMD's director of strategic marketing. "There are a ton of device drivers that have already been written, and the operating system has a bunch of built-in drivers," he said. Companies that have already developed 64-bit drivers include Adaptec, Brother and Creative Labs, according to AMD's website.

Sixty-four-bit systems process more data per clock cycle, allow access to more memory at a time, and speed numeric calculations. Microsoft has worked with AMD to develop 64-bit operating systems for its Athlon and Opteron chips. Athlon is meant for use in desktop computers and Opteron for server systems; 64-bit operating systems have been available on the competing Unix platform for years.

One key benefit of 64-bit extension technology and Microsoft's 64-bit operating systems is that applications written for 32-bit computers will still work with processors that can run 64-bit software. However, that isn't true for device drivers, said Tom Phillips, general manager of Microsoft's hardware experience group.

"Applications are generally running up in user land. In kernel land, there is a far different development environment, and we don't have the luxury of running software" that isn't completely compatible with the hardware, he said.

Selling the company's next wave of products, Microsoft expects significant adoption of 64-bit systems and, predicted Gates, by the end of 2005, all AMD and most Intel processors will support 64-bit computing. On the server, 64-bit will be common within the next couple of years, and desktop users will want to reap the benefits of the capabilities, he said. Intel earlier this year followed AMD in announcing a processor with 64-bit extensions technology.

Wright agreed with Gates' prediction. "By the end of 2005, all we will be shipping is AMD 64," he said.