The parallel 64-bit universe

Two years back, Intel launched its big challenge to the server-processor status quo with Itanium, intended to bring commodity architecture to the rarefied world of high-end servers. Now AMD's Opteron and Apple's G5 processors are, in their different ways, beginning to encroach on territory formerly controlled by Intel's Xeon as well as proprietary RISC/Unix vendors such as Sun, HP, IBM and others. Both Apple and AMD's chips are used across server and desktop platforms, and are 64-bit capable -- although this is something of a stealth feature in the near term.

Of the two companies, AMD is far more aggressive at targeting the enterprise, although analysts say Apple has the potential to erode Unix and even Linux server market share. Both companies have traditionally been left out of large businesses, and have only recently come up with products suitable for servers. If these companies have their way, they stand to turn the server world on its head by making 64-bit technology commonplace.

64-bit revolution?
There is nothing particularly new about 64-bit computing, as pundits never tire of pointing out: mainframes have been using it for years, for example, and most flavours of Unix and even Linux support 64-bit processors. But most corporate IT was designed on 32-bit Windows machines, so that the potential ubiquity of 64-bit platforms at the desktop and server level -- even if that potential is little-used in the near future -- is a big shift indeed.

Sixty-four-bit processors are very efficient at handling very large numbers in large financial systems, computer simulations, CAD/CAM workstations, graphics rendering and encryption. The chips are also at an advantage where it comes to addressing memory, important for large databases: 32-bit chips max out at 4GB of memory, while the Opteron can address a terabyte (1024GB), and the G5 can handle 8GB. The theoretical limit for 64-bit processors, by the way, is more than one trillion terabytes. All this adds up to significant advantages for particular types of applications.

Different approaches
Where the G5 and the Opteron have broken the mould is that they are backward-compatible with older software, meaning you can run all the existing Unix, Linux or Windows software you like on them, and upgrade individual applications as needed. This is a radically different approach from the route Intel took with Itanium: that chip uses a completely different instruction set, and can only run 32-bit software through a bolted-on emulator that, so far at least, has delivered unpromising performance. Under Intel's system, you need to migrate to 64-bit computing in one uncomfortable jump; with the Opteron or the G5, you can mix and match.

The new 64-bit chips are also selling at a fraction of the cost of Itanium; the Opteron is priced to compete with the 32-bit Xeon, for example. If the Opteron does as well as AMD hopes, it could create a ready-made 64-bit market, which could spur the development of 64-bit software. Ironically, this would actually be a boost to the Itanium platform, since software written for 64-bit Windows or Linux running on the Opteron could be relatively easily ported to 64-bit Windows or Linux running on the Itanium. At the moment, little 64-bit software exists for Itanium, as the market is so small -- a fact which in turn has dampened the chip's growth.

These new developments, while revolutionary, are going to take a while to even begin to play out. Today, you can buy an Opteron server running a 64-bit operating system and software, but the software you can choose from is limited (it will probably be Linux) and so is the hardware (it will probably be IBM). Apple's G5 and the Panther Server software to take advantage of it are also here today, although we are still waiting for a G5-powered Xserve. A significant development will be next year's release of a 64-bit version of Windows XP for Opteron, although even then it is likely to be missing a number of features, not to mention 64-bit drivers; some time after that a 64-bit version of Longhorn, the next generation of Windows, will follow. On the Mac, things are likely to proceed a bit more quickly with Panther already supporting some 64-bit functionality. AMD itself predicts that 64-bit applications won't be widespread until 2007. But in the bigger picture, even that will be a quick transition: after all, it took 15 years after the introduction of Intel's first 32-bit chip for Microsoft to release its first fully 32-bit operating system, Windows XP.

The Opteron

The Opteron is AMD's "first mature commercial product" for the enterprise, says Simon Cole, marketing manager for AMD, and it emerged largely out of necessity. AMD couldn't match the massive 10-year research and development effort that went into creating the Itanium, so instead went with the more straightforward approach of extending the 32-bit x86 instruction set, into what it calls x86-64. While Intel's Itanium runs 32-bit applications slower than most Pentiums, Opteron's best selling point in the immediate term is its ability to deliver blazingly fast 32-bit performance.

In fact, despite all the hype around 64-bit computing, AMD is principally targeting the market usually associated with conventional 32-bit server chips in two and four-way configurations. "We are positioning it more against the Xeon than anything else," says Cole. "But we are also telling people that they're buying equipment that's going to be capable of running 64-bit software in the next couple of years or so. Then they can look at the advantages of the new 64-bit software, and decide for themselves."

The G5

Apple's traditional home territory has been creative professionals who rely on the Macintosh's powerful content-creation software, but the company became relevant to the server world with the release of Mac OS X, the company's new-look operating system built on the BSD flavour of Unix. The Xserve rack-mounted server, announced in May 2002, was OS X's first foray into the enterprise space, using G4 hardware.

The hardware took a leap forward in June with the 64-bit G5 chip, jointly developed with IBM and also known as the PowerPC 970. It bumps the Mac's processor speed from a maximum of 1.2GHz to 2GHz, with a 3GHz G5 promised within a year. The top-of-the-line G5 system uses a speedy 1GHz system bus, the component connecting the chip to the motherboard and main memory modules, while low-end and midrange models use 800MHz and 900MHz system buses, respectively. The new systems all use faster 400MHz DDR memory, up from the G4's 333MHz DDR SDRAM. The top-of-the-line system costs £2,299, with the 1.8GHz single-processor system selling for £1,849 and the 1.6GHz system costing £1,549.