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The 64-bit versions of Windows XP Professional and Windows Server 2003, when combined with systems based on Advanced Micro Devices Inc.s x86-compatible 64-bit chips (or work-alike variants from Intel Corp.), let organizations boost the performance of memory-intensive applications without giving up 32-bit cold turkey.
In eWEEK Labs tests, Windows x64 (x64 is Microsoft Corp.s name for the 64-bit AMD architecture) did a good job of juggling 32-bit and 64-bit applications running together on the same machine, which can be tricky to manage. Microsofts Internet Explorer ships with both 32-bit and 64-bit on Windows x64, and each has its own versions of various libraries that need to be kept straight.
Management can be problematic because, although AMDs architecture allows for native execution of 32-bit applications, Windows x64 (or any other 64-bit operating system weve tested) wont brook mixing 32-bit and 64-bit code. This is why code that runs in kernel mode, such as that used for hardware drivers or firewall anti-virus applications, must be ported to work with Windows x64s 64-bit kernel.
We installed Windows XP Professional x64 Edition on a Hewlett-Packard Co. xw9300 workstation with dual AMD Opteron processors and found that Windows lacked a driver for the machines on-board NIC. We tried an Intel PCI NIC next, and it worked fine.
We couldnt locate a Windows driver for the systems on-board sound, either. The only Windows x64 drivers available on HPs Web site for the system we tested were those for the systems Nvidia Corp. graphics adapter.
On a superficial level, Microsofts two new operating system editions are essentially identical to their 32-bit siblings, but Windows x64 manages multiple-architecture complexity by maintaining separate locations for 32- and 64-bit program files and libraries and by presenting separate registry views for the different architectures, which prevents settings conflicts for applications installed in both 32-bit and 64-bit forms.
In addition, the task manager in Windows x64 shows whether the applications that are running are 32-bit or 64-bit versions .
We recommend that sites running Windows on servers powered by AMDs Opteron and AMDs Athlon 64 or Intels EM64T (Extended Memory 64 Technology)-enabled Xeon and Pentium IV—particularly with memory-intensive applications—begin testing and planning for a move to Windows x64. Provided that the proper drivers are available for your hardware, a shift to x64 on servers that support it should be a slam-dunk because the new platforms benefits can extend to 32-bit as well as 64-bit applications.
We also recommend that Windows developers get a copy of Windows x64, if they havent already done so, to begin preparing their applications—and, in particular, their drivers—for the new platform. AMD and Intel are both pushing x64, and now that Windows x64 has shipped, it wont be long until new mainstream systems are 64-bit-enabled.
For desktop and workstation users, who are much less likely to be running systems with tons of RAM, the decision of whether or when to move to 64-bit Windows depends most directly on applications designed to take specific advantage of the new platform.
As with server implementations, applications with heavy memory demands, such as those for CAD or video editing, will see the greatest direct benefit.
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The No. 1 deliverable of 64-bit is a significant boost in the amount of memory a system can use. At the high end of the Windows line, Windows Server 2003 Data Center x64 Edition supports up to 1TB of RAM, compared with 64GB of RAM for the Data Center version in 32-bit. Likewise, Windows XP Professional x64 Edition supports 128GB of physical RAM, compared with 4GB of RAM in the 32-bit version. The x64 editions of both Windows Server 2003 and Windows XP Professional are available now.
More RAM means fuller processor use and potentially better performance because systems running Windows x64 can feed more data to the processor per clock cycle and reduce swapping to disk by loading and retaining more work in RAM.
One of the most dramatic cases for upgrading to Windows x64 is that of Windows Terminal Server: With 32-bit Windows, the number of Terminal Services users that a machine can support is capped by the platforms 2GB kernel space limit. In Windows x64, this limit has been expanded to 8TB of kernel space and 8TB of user space, which means sites with RAM-stacked servers can take better advantage of those resources today and have a good deal of headroom for future expansion.
You might also bump into trouble mixing 64-bit code with 32-bit IE plug-ins—nearly all of them—and with add-ons for the Windows Explorer graphical shell. Windows x64 ships with 32-bit and 64-bit versions of IE but only 64-bit Windows Explorer.
In addition, Windows x64 wont run 16-bit code, which tends to lurk in easily overlooked portions of applications such as installer tools. These 16-bit programs must be rewritten to run on Windows x64. In a few of these cases, such as with some InstallShield Software Corp. and Acme installers, Microsoft has coded Windows x64 to recognize the incompatible 16-bit installers and transparently substitute included 32-bit versions during the applications install process.
Another potential trouble point is Windows Server 2003 Service Pack 1: Both versions of Windows x64 are based on the Windows Server 2003 SP1 code base, so sites experiencing application compatibility issues with the new service pack will need to get them straightened out before deploying Windows x64.
The Windows x64 editions arent Microsofts first 64-bit operating system forays; the company has been shipping versions of Windows XP and Windows Server 2003 for Intels Itanium platform for the past few years. However, the Windows x64 editions ship with a fairly long list of services and applications that Microsoft left out of its Itanium port.
Windows components making their 64-bit debut in these releases include Windows Firewall and Security Center, support for DVD video playback, Windows Messenger, Remote Assistance, Power Management, System Restore and Bluetooth.
Next page: Migration has its rough spots.
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Microsofts x64 editions of Windows XP Professional and Windows Server 2003 enable organizations to get the most out of their AMD64- and EM64T-based hardware. However, while processors based on these architectures natively run most existing 32-bit applications without a hitch, sites contemplating the upgrade need to watch out for these potential 32/64-bit trouble spots:
- 32-bit hardware drivers and kernel-mode applications must be ported to run on Windows x64. AMD has assembled a list of compatible drivers and applications at www.amd.com/us-en/Processors/DevelopWithAMD/0,,30_ 2252_869_875%5e10454,00.html?redir=IEGFC07.
- Windows x64 wont run 16-bit code. Microsoft provides some workaround information for this issue at support.microsoft.com/?kbid=896458&SD=tech.
- Windows x64 editions drop support for a number of legacy protocols and subsystems, including MS-DOS, OS/2 and POSIX subsystems and the IPX/SPX, AppleTalk, Services for Macintosh, DLC LAN, NetBEUI, IrDA and OSPF protocols.
Source: eWEEK Reporting
Senior Analyst Jason Brooks can be reached at jason_brooks@ziffdavis.com.
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