By Michael Cherry [bio]
- Illustration: 64-Bit Software and Processor Roadmap
The following is the full text of an article published by Directions on Microsoft, an independent research firm focused exclusively on Microsoft strategy & technology. Each month we make one or more key articles available to non-subscribers.
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(For an overview of Microsoft's 64-bit plans, see "64-Bit Software and Processor Roadmap".)
Exchange Moves First
One of the first Windows Server System products to be available only in a 64-bit edition will be the next version of Exchange (code-named Exchange 12), which is due for release in late 2006 or early 2007. (This version will run on x64 processor designs, produced by both AMD and Intel, but not on Intel's 64-bit Itanium processor). Microsoft says it needs to move Exchange to 64 bits because e-mail is a mission-critical application and Exchange customers are telling Microsoft that their current systems are being pushed to the limits of physical memory due to increases in the following:
- Volume of e-mail
- Average e-mail message size
- Use of attachments
- Average size of attachments
- Number of users per server as a result of server consolidation
- Number of different mail clients as users begin to access their mailboxes via Web and mobile device clients in addition to Outlook.
Microsoft says that the 64-bit edition of Exchange will allow customers to add memory rather than servers to address increasing e-mail demands. In addition, the move to 64-bit will also help customers gain benefits from storage systems—on 64-bit systems the amount of memory available for caching data may reduce the number of I/O operations by 70%.
Current 32-bit applications can overcome Windows Server's 4GB memory limit by using technologies such as Physical Address Extension (PAE) or Address Windowing Extensions (AWE). However, although this increases the amount of addressable memory, it has many limitations, and Microsoft claims that a 32-bit version that used these extensions would not have addressed the memory and performance issues that customers are experiencing.
In addition to benefiting customers, the move benefits Microsoft, which will be able to streamline development by putting the 32-bit versions into maintenance mode, fixing only serious bugs and vulnerabilities and eliminating the need to synchronize and test builds for different processor architectures. This will free up more resources for improving the 64-bit edition.
The decision might also be partly driven by market conditions: AMD and Intel x64 processors have gained sufficient market share that Microsoft can afford to exploit the x64 architecture to build a more powerful Exchange Server.
Finally, Microsoft might believe that it can move more aggressively to 64-bit with Exchange because it will be less expensive, even for reluctant customers, to upgrade their servers rather than to migrate to other e-mail products. However, it could also reduce momentum for Exchange 12, as customers who would be willing to risk an in-place upgrade of Exchange 2003 balk at the triple upgrade—new hardware (unless they have previously deployed 64-bit hardware with a 32-bit OS), new OS, new server application—required by Exchange 12. Furthermore, because Exchange 2003 will not run at all on 64-bit editions of Windows today, customers cannot migrate gradually to the next version.
Small and midmarket customers and partners may be surprised by the 64-bit requirement. Two products aimed at that market—Small Business Server (SBS) and "Centro" (the code-name for a planned set of server infrastructure technologies for midsize businesses)—include an Exchange component. With the next version of Exchange available only for 64-bit systems, future versions of SBS and Centro will also require 64-bit hardware and OSs.
Impact on Windows
With the Windows OS itself, Microsoft will move more slowly to avoid ceding any portion of the OS server market to Linux.
Windows Vista, the next client OS version, will be delivered with both 32-bit and x64 editions in late 2006. Even the subsequent Windows client (Vista R2, likely due in late 2008 or early 2009) may be available in a 32-bit edition.
Similarly, the next major update to Windows Server (code-named Longhorn Server and due in mid- to late 2007) will also be available in 32-bit and x64 editions. The plan of record still includes an Itanium edition, but this will depend on demand and whether the Itanium processor has been eclipsed by x64 processors.
Windows Computer Cluster Server 2003, a new version of Windows for high-performance computing, will be x64 only.
Processor Change Complicates Migration
Although AMD and Intel have been shipping x64-based processors for some time, x64-based editions of Windows have been generally available only since Apr. 2005. Due to the lack of some 64-bit device drivers and 64-bit versions of critical software, such as antivirus and specialized backup utilities, a large number of OEMs still sell x64-based systems with 32-bit editions of Windows Server. Once these servers are in place with a 32-bit OS, there are no tools or support for doing an in-place upgrade.
Therefore, many systems initially deployed with 64-bit hardware may never be upgraded to a 64-bit OS—particularly 64-bit systems purchased today with 32-bit Small Business Server preinstalled. Many small businesses don't have the resources for this significant migration and are too small to experience the performance problems that Microsoft says mandate the move to 64 bits.
Microsoft's virtualization software is also caught in the 64-bit transition. Many organizations use virtualization technology to aid systems management, as it enables them to configure and manage multiple independent "guest" OS installations and their applications on a single server. However, Microsoft's virtualization software does not support 64-bit guest OSs today, and it will probably not do so until at least one year after Exchange 12 ships, which means that customers might have to turn to virtualization products from other providers, such as VMware, in the interim. (For more information on Microsoft's plan for its virtualization software, see "Changes to Server Virtualization Roadmap" in the January 2006 Update.)
Still Supporting 32-Bit
Microsoft will still support the existing 32-bit editions throughout their published Mainstream and Extended life cycle, but it is important to understand what this support entails.
Specifically, Microsoft may choose to release patches for bugs and vulnerability updates as it sees fit, but such support may or may not include future service packs. Regardless, any architectural changes made to the 64-bit editions—even security improvements—may not be back-ported to the 32-bit legacy versions.
Resources
The x64 processors and their advantages are described in "New 64-bit Options Aid Performance, Security" on page 3 of the July 2005 Update.
Centro and Microsoft's midmarket plans are described in "Server Bundle for Midsize Businesses" on page 5 of the Sept. 2005 Update.
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