Recently, Microsoft has been "priming the pump" and demonstrating early releases of 64-bit Windows 2000 designed to run on Intel's upcoming Itanium (formerly known as Merced) 64-bit processors. Word on the street is that Microsoft plans to release an early beta of 64-bit Win2K later this summer. Microsoft has been telling everyone it will ship the final version of 64-bit Win2K at the same time Intel delivers its IA-64 chips. Microsoft has been building the 64-bit flavor simultaneously with the 32-bit Win2K for several years now. Don't worry: Microsoft plans to keep shipping 32-bit Win2K for at least another 10 years. So what does 64-bit Win2K mean to Exchange Server?
For Exchange Server 5.5, the answer is "nothing," because Microsoft didn't build this version to take advantage of a 64-bit environment (and has no plans to do so). Although Microsoft hasn't announced any specific 64-bit support for Exchange Server 2000, 64-bit Win2K presents many possibilities for Exchange 2000. The Exchange Server development team has been working on 64-bit support since before Intel's IA-64 prototypes were available by using Compaq's 64-bit Alpha chip as a development platform. One benefit of a 64-bit environment is the large addressable memory space available for applications such as Exchange 2000. Exchange 2000 could definitely benefit from a larger memory space in storage group scalability. At release to manufacturing (RTM), Exchange 2000 will support a maximum of four storage groups. Storage groups are instances of the Extensible Storage Engine (ESE) that manage a set of transaction logs and database files. One reason Microsoft limited to four the number of storage groups in the RTM release is memory limitations in 32-bit Win2K (the other reason is the degree of testing required to support a full complement of storage groups). Technically, Exchange 2000 will support up to 15 configurable storage groups. However, even on systems with large amounts of physical memory, you can't configure 15 storage groups without running out of virtual and physical memory. A 64-bit version of Win2K running a system with large amounts of physical RAM would help alleviate the memory problem and let 15 storage groups run on a production server.
Although 64-bit support for Win2K is still in the future, many organizations have plans for their Exchange Server deployments that will require the benefits that a 64-bit OS provides. It's nice to know that the Exchange development team is on the cutting edge with 64-bit technology and will provide support for Exchange Server when the timing and implementation are right.