The next big monkey out of the Microsoft zoo, Windows 64 isn't yet a reality for most of us. It appeared in winter 2001, but few of us outside the geekerati have ever seen one, much less gotten our sweaty paws on one. However, the Intel Itanium 64-bit microprocessor has long since made its public debut, and Microsoft has an ace up its sleeve. Win 2K, already a fixture on the market, is 64-bit compliant and ready to work with an Itanium-based PC (well, OK, they'll release a 64-bit version of Win 2K -- the copy you own won't run on a 64-bit platform). Windows Millennium is strictly 32-bit and won't run a 64-bit chip, and Windows XP hasn't yet been recompiled for 64-bit processing, either. The Itanium chips are backwards-compatible, which means that they will run our 32-bit programs and applications (although they won't run the old 16-bit fellows any more, nor will they run old DOS-based programs). (Four different operating systems will support the Itanium: 64-bit Windows, HP-UX, IBM AIX-5L, and Linux. The Itanium is compatible with x86 code, but is better suited to running native code programmed for the IA-64 architecture.) It's pretty evident that the Win 64 OS will be directly descended from the NT line of Windows and not the 9x line, which is scheduled to come to an end with Millennium and the hybrid XP. Does this mean that you should junk your "old" Pentium- or Athlon-driven computer? Not at all. 32-bit computing will be with us for years and years, and even now that Itanium has made its appearance, it's not useful to us home PCers. It focuses strictly on commercial use for now, competing with the Sun UltraSPARC chip as opposed to the PC chips we all know and, er, love. You diehards who won't give up your 16-bit utilities are not going to be happy with the events of the near future, though. And don't look for Itanium on your local CompUSA shelves any time soon; instead of being offered as a standalone package, it will be loaded onto Itanium-based PCs. More info on Win 64 is available from www.intel.com/itanium/. AMD has gotten into the act with a 64-bit chip; the personal PC version is called Clawhammer, while the server chip revels in the name Opteron. Find out more from www.amd.com/products/cpg/64bit/overview.html. There's also an Athlon 64 chip now on the market. AMD will probably be the first to hit the mass market with a personal 64-bit computer, but unless you're running Linux, you won't see a 64-bit operating system for personal use until 2004.

By the way, neither Intel nor Microsoft invented 64-bit computing. 64-bit chips from manufacturers such as DEC, Motorola, Sun, Silicon Graphics, and others (even Nintendo) have been making 64-bit CPUs for years. None of these chips run Windows particularly well, though Win NT had a 64-bit version that ran on the DEC Alpha system with decent results. But that hasn't mattered. After all, there still is no 64-bit version of Windows, and no 64-bit Windows applications either. These chips run 64-bit flavors of Unix, VMS, and other operating systems. Unfortunately, each chip runs things its own way -- software written for the DEC chip won't run on the Sun chip, and so forth. Intel's contribution to the 64-bit wars is just as proprietory, as is AMD's. Both Intel and AMD hope that their version of the 64-bit chip will be the one to win the Windows battle; the bad news for AMD is that Microsoft is so far only promising to develop an Intel-compatible version of Win 64. Does that mean that AMD is beaten before it starts? Not necessarily. The AMD 64-bit chip will run 32-bit software as well as an Intel chip; also, a version of Linux for AMD 64 is in the works. So when will we see the Itanium chip on the WalMart shelves? Good question. It was originally due to be released in fall 2000 (well, if you insist on being sticky, it was originally slated for release in 1997), but was pushed back several times. Even though it has technically already hit the market, as noted above, few of us have actually seen a 64-bit machine. (Wags have noted the missed due dates and other problems, and dubbed it "Itanic.") Like the scheduled AMD offering, the first Itaniums were released for servers and workstations, with the chip slated to appear on desktops much later.

Intel's first 64-bit chip hit the market in two speeds, 733 MHz and 800 MHz, in May 2001. Very few applications are available to run on the new platform as yet, but they're in the works. The next chip in the Itanium family, formerly McKinley but now the Itanium 2, has just hit the market. It clocks at almost twice the performance of the original Itanium and, of course, is strictly for servers and workstations for the moment. AMD's own 64-bit offerings, Clawhammer and Opteron, are just out, and while the PC geeks are thrilled by the chips, the rest of us haven't had much dealings with them. Sun is striving to keep up with the release of the 900 MHz UltraSPARC III chip, which appeared in late 2001. Home users like us don't need to get too excited yet -- we're still waiting to see what 64-bit apps come out when, and more importantly, when 64-bit computing hits the home- and small business PC market. How well will 64-bit chips run the "old" 32-bit apps we know and love? Early indications are that the AMD chips will be much friendlier to 32-bit apps than the Intels, but that may change, particularly as Intel refines the McKinley chip. On the other hand, the AMD chips are based on the old x86 chip architecture while the Itaniums use a newly crafted instruction set written specifically for the 64-bit chips. The old flaws and limitations in the x86 instruction set will carry over to the 64-bit AMD products, while the Intel chips won't carry those old glitches. Of course, the new instructions will have their own glitches....

Why don't the majority of us care about 64-bit computing for ourselves? Well, the home software market is completely 32-bit as of this writing. It's tough to find a decent office suite that's 64-bit compliant, and don't hold your breath waiting for a 64-bit version of The Sims. Secondly, unless you work with CAD, professional 3D, scientific modeling, or high-end database tools, you won't get the full benefits of 64-bit technology. That's as of now (mid-2002). We'll see how things change.