64 BIT COMPUTING

In 1986, Intel introduced its first 32-bit CPU. It wasn't until 1993 that the first fully 32-bit Windows OS--Windows NT 3.1--followed, officially ending the 16-bit era. Now 64-bit processors have become the norm in desktops and notebooks, though Microsoft still won't commit to an all-64-bit Windows. 64-bit versions of Windows have been around since Windows XP, and 64-bit CPUs have been with us even longer. In fact, virtually every computer sold today has a 64-bit processor under the hood. At some point Microsoft will have to jettison 32-bit altogether, as it did with 16-bit when it launched Windows NT, if it wants to induce consumers to upgrade. That isn't likely with Windows 7: The upcoming OS is already being demoed in 32-bit and 64-bit versions. But limitations in 32-bit's addressing structure will eventually force everyone's hand; it's already a problem for 32-bit Vista users, who have found that the OS won't access more than about 3GB of RAM because it simply doesn't have the bits to access additional memory.
Expect to see the shift toward 64-bit accelerate with Windows7; Microsoft will likely switch over to 64-bit exclusively with Windows 8. That'll be 2013 at the earliest. Meanwhile, Mac OS X Leopard is already 64-bit, and some hardware manufacturers are currently trying to transition customers to 64-bit versions of Window.