The driver requirements for Leopard are much looser. Hardware vendors can create 64-bit Mac OS drivers once there's sufficient demand, since they know their 32-bit drivers will work just fine with the 64-bit applications on Leopard, Croll said.
Some applications require the extra performance delivered by 64-bit drivers, but most don't, at least not right away, McCarron said. "The sacrifice that's being made here is fairly small, and affects a small set of users."
However, Barry Goffe, a director in the Windows group, said things are easier for Apple. Microsoft feels that in order to bring 64 bits to the world while ensuring interoperability with the vast amount of devices and software available for Windows, it has to specify a standard driver development model.
"The variety and diversity of devices and the quantity of developers that Windows supports is probably several orders of magnitude greater than the limited number of developers that Apple supports," Goffe said. "The problem they are trying to solve is a much smaller problem."
McCarron said one advantage of Microsoft's approach to driver development is that it will force the development of cleaner device drivers. "Because it's one of the few pieces of third-party software that shows up in the protected area of the OS, drivers can really screw things up," he said.
The 64-bit driver situation is improving for Vista systems. Thanks to years of work -- and the delay in consumer adoption -- 64-bit driver coverage is actually pretty high considering there are few actual users of the 64-bit operating systems, according to Microsoft.
"The issue with drivers is already less of a gating factor," Goffe said, noting that Microsoft required that for its premium "Certified for Windows Vista" logo, companies have a 64-bit driver.
"The real issue that's in front of us around broad usage of 64-bit comes back to the applications," he said. "It's a little bit of a chicken and egg kind of thing. There aren't a lot of mainstream 64-bit capable apps yet."
Microsoft expects the transition to take more time, said Michael Sievert, the corporate vice president in charge of product marketing for Windows.
"Usually something comes along that is a catalysing force," Sievert said. "Each time we've made one of these migrations it's been something that takes time."
Apple agrees that this transition won't happen overnight. It will first emphasize 64-bit applications for its base of users in the graphic design world, who buy systems such as the Mac Pro workstation to run applications with large data sets, Croll said. That system can already be configured with up to 16GB of memory, and will probably serve as Apple's test bed for 64-bit applications.
As for the mainstream users, "the 64-bit pieces of the puzzle are going to be in place a couple of years from now," McCarron said. "The burden will be on the OS side, and the applications will follow."
Has any one had these problems with linux, im keen to know as im about to try it my self.