Hewlett-Packard (HP), Dell, and other OEMs are finally selling workstations and servers that incorporate Intel's Itanium (formerly code-named Merced) chip, the 64-bit microprocessor that was originally due to market in 1998. Microsoft is weighing in with preview versions of its 64-bit Windows XP and Windows .NET Server products and will offer free upgrades to the final versions of these products by the end of 2001. Although the initial market for these 64-bit products is likely to be small, migrating to this superior platform will be a requirement eventually.
The First Generation
Microsoft recommends that most of its customers not upgrade to 64 bits. Why? Like Itanium, 64-bit Windows is a work in progress and in its current stage of development can't offer the full performance or functionality of a mature platform. Perhaps more important is that today, few people need 64-bit processing or 64-bit applications (a convenient circumstance, given that 64-bit applications are rare).
Microsoft has dubbed its preview 64-bit versions of XP and .NET Server the Windows XP 64-bit Edition and the Windows Advanced Server Limited Edition, respectively. When XP ships in October, Microsoft will release the final version of Windows XP 64-bit Edition, alongside the 32-bit XP Home and Professional editions. By the end of 2001, Microsoft plans to ship Windows Advanced Server and Windows Datacenter Server in final 64-bit versions; these versions will also ship alongside 32-bit Server, Advanced Server, and Datacenter. All 64-bit Windows products will be available exclusively from OEMs.
What It Is
For applications that need massive amounts of memory—databases and data warehousing, for example—64-bit Windows running on Itanium will fill the bill. The platform supports 16TB of flat virtual address space, and base Itanium workstations ship with at least 1GB of RAM. Two-processor systems start with 2GB of RAM. Microsoft SQL Server 2000, which will ship in a 64-bit edition by the end of 2001, is Microsoft's first non-OS 64-bit port. Microsoft is also porting Visual Studio (VS) and Services for UNIX (SFU) to the 64-bit platform. On the desktop, the 64-bit future is unclear. Microsoft's Office team is evaluating a 64-bit version of Office 11 but has made no announcement about the product's viability.
Microsoft has designed its 64-bit Windows products in tandem with the 32-bit line, which simplifies the conversion process—only a recompile for 64 bits is necessary to bring most applications over to Itanium. Application developers will find that working with 64 bits is likewise relatively simple (although Microsoft won't support access to DOS and 16-bit subsystems and hardware-specific code).
What's missing in this first generation of 64-bit Windows? Surprisingly little. In general, the XP and Windows .NET Server 64-bit versions will be on par with the corresponding 32-bit releases. And Windows 32-bit applications will run just fine on Itanium, thanks to the WOW64 emulation layer. For desktop applications, this emulation layer will lower the cost of migration. However, Microsoft doesn't recommend running server applications or services with WOW64 but rather upgrading these mission-critical components to the native 64-bit environment before deployment.
The Future of Windows
Do you need 64-bit Windows today? Unless you have specific data-mining needs, I recommend that you hold off until 64-bit systems based on the second generation of IA-64 (code-named McKinley) chips appear. These systems will be widely available by the end of 2002, according to Intel and its partners. By then, we'll have seen various performance enhancements, smarter compilers, more native applications and services, and a wider range of addressed solutions. Intel's 64-bit family is the future of Windows. The only question is when that future will arrive.