What 64-bit Windows XP Means to You

Though 64-bit processors for PCs and other devices have been available for over two years now, whatever urges might arise to migrate to those new platforms have been stymied by a whole bunch of factors. Intel's had to work through at least four generations of 64-bit CPUs (Itanium, Itanium 2, Xeon, and Nocona) to figure things out, and while AMD's Athlon 64 and Opteron chips have been something of a hit with PC users, wholesale abandonment of 32-bit hardware in favor of 64-bit alternatives is not yet a done deal.

The answer to the inevitable "Why?" that these revelations may provoke could be phrased in Clintonesque cant as: "It's the software, stupid"—or rather, the lack of native 64-bit software that can take full advantage of what 64-bit hardware can do. Today, most people who buy 64-bit PCs can realize modest performance advantages by emulating 32-bit processing in a 64-bit world, but they really can't exploit the huge memory spaces, faster data transfers, richer instruction sets, and other features that 64-bit architectures can provide.

For Windows PC users, that's about to change. Not only are more application developers starting the laborious process of migrating their code bases to 64-bit versions (and making the necessary internal changes to take advantage of what 64-bit processors and architectures can do), Microsoft itself is now getting into 64-bit gear. Microsoft already has a Web page up for an upcoming new version of Windows XP—namely, Windows XP Professional x64 Edition—where anybody who's interested and has access to the right software can download pre-release trial software already (called Release Candidate 1, or RC1.) In fact, Microsoft plans the production release of this software in mid-2005, three or four months after this story is being written.

What are curious or interested potential users of Windows XP Professional x64 Edition likely to find under its hood? Here's a short list of features and functions, with notes about how they relate to hardware currently available or under development:

	Huge memory spaces: 64-bit operating systems have a theoretical upper bound on memory size of 16 exabytes. However, RC1 supports 32GB of RAM, and plans for the final release version are for 128GB. (Most 64-bit systems currently available or on the drawing board won't support more than 8GB of physical memory, except for servers. This is still 4 to 5 times more than 32-bit desktops can handle, however.)
	Windows XP Service Pack 2 (SP2) functionality: RC1 matches what's in Windows XP SP2, including the Security Center, Windows Firewall, Automatic Updates, and a security-enhanced version of IE 6.0 with Pop-up Blocker, active content monitor, and so forth. There are two versions of IE provided: 32- and 64-bit. That's because 32-bit IE plug-ins such as the Google Toolbar, Adobe Reader, or the Flash player won't work with the 64-bit version—at least not yet, anyway.
	The 32-bit version of Windows Media Player 10: This is included with RC1, as are 32-bit versions of many native Windows tools and utilities.

It's almost as interesting to list what's not included in Windows XP Professional x64 Edition RC1 as to state what's new and different. It looks like Microsoft is finally flushing some last vestiges of legacy applicati ons, tools, and services from the older and less visited regions of its code space:

The Windows on Windows (WOW) and Windows Virtual Machine (VM) subsystems that support 16-bit DOS and Windows applications are gone, gone, gone. It will no longer be possible to run 16-bit applications in this environment.

Older, infrequently used network protocols like NetBEUI, AppleTalk, and original NetWare protocols SPX and IPX have all been excised.

Many 32-bit programs still use 16-bit installer programs to load themselves into Windows, so many programs that install without a hitch on 32-bit Windows XP simply won't install on Windows XP Professional x64 Edition. Surprisingly, this even includes some Microsoft programs—both supported software like Photo Story 3 and unsupported software like Windows XP PowerToys. Once over the install hurdle, most 32-bit applications work reasonably well, but occasional glitches do occur.

32-bit device drivers won't install into the current RC1 version of x64. The install package includes lots of 64-bit drivers, but inevitably some devices still lack the necessary 64-bit drivers to make them work in this environment.

You can't upgrade from Windows XP Professional to x64; it's necessary to perform what's called a clean install. Alas, this means backing up all data, settings, and so forth; wiping the drives; installing x64 on a bare machine; and then reinstalling all applications. Ouch!

In the short run, 64-bit Windows is likely to appeal only to leading-edge/bleeding edge kinds of computer users, such as developers who will be building or revising applications for the 64-bit world. (Let's hope this also includes others who'll be creating 64-bit drivers for all the hardware that people are likely to want to use on such machines.) This initial cadre of early adopters also includes graphics professionals who can realize immediate benefits from improved graphics and visualization capabilities that 64-bit environments deliver. Graphics designers, animators, game builders, and 3-D modeling and video professionals are likely to flock to this platform (or to the 64-bit Macintosh G5 platform, also due out later this year). Likewise, anybody who uses math-intensive or engineering applications that crunch lots of numbers are also likely to find support for faster processing of bigger numbers appealing.

However, it won't be until common applications go 64-bit and hardware architectures expand to accommodate bigger memory spaces that common, garden-variety users will start to find compelling reasons to move into this world. Because even 8GB of RAM in 2GB increments (which currently retail for over $1,000 bucks a pop) will almost certainly cost more than a high-end system, memory prices may serve as a serious constraint on "moving up" for the next year or two.

But with Microsoft moving aggressively into 64-bit territory and application and device driver developers flocking close behind, there's probably a 64-bit desktop somewhere in your future. And for all I know, that future might not even be too terribly distant.


The preceding commentary is provided solely by the author and does not necessarily reflect the viewpoint of CramSession.

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