If any modern technology has earned the term venerable, it's Intel's 32-bit processor architecture. Even today's newest Pentium computers have an architecture deeply rooted in the 286 and 386 processors of more than a decade ago. The 32-bit architecture has served us well, acting as the primary hardware platform for every version of Windows NT, but it's definitely time for something new: Intel's 64-bit Itanium processor family.
Servers based on these 64-bit processors are already available, and Intel is hard at work on new editions of the Itanium processor that run faster and provide additional features. Microsoft provided Windows Advanced Server Limited Edition?essentially a pre-release, production-ready version of 64-bit Windows Server 2003?to give 64-bit servers a network operating system, and of course Windows Server 2003 offers two 64-bit editions. But there's a great deal more to 64-bit computing than a new processor and operating system. Itanium servers include a new memory architecture, new peripheral bus, new disk-handling mechanisms, and much, much more. This chapter provides you with an overview of the world of 64-bit computing, introduces you to the 64-bit hardware platform, and shows you how 64-bit Windows differs from its 32-bit cousin. It also explains how Windows Server 2003's 64-bit editions provide compatibility for your existing 32-bit applications, so that you're not left to scramble for new versions of your software.