The importance of being 64-bit

At the launch of Microsoft's 64-bit versions of Windows XP and Windows Server 2003 late last month, Bill Gates promised great things for the "64-bit decade". The transition from 8-bit computing to 16-bit required a reinvention of the operating system, and even moving to 32-bit ten years later was still a bit messy. But the shift to 64-bit hardware and software will be different, according to the Microsoft boss. "This is going to be the simplest one, and it's going to happen far more rapidly than any of the others," Gates claims.

Gates may have a clear vision of the significance of 64-bit but that doesn't necessarily mean that all his potential customers are similarly informed. Many IT professionals in enterprise-sized companies, and their smaller brethren, are probably at a loss over exactly what the benefits of 64-bit are — a knowledge gap that Microsoft has to tackle for the technology to really take off.

But along with the carrot of potential benefits Microsoft will also be wielding the usual stick of forced compliance. A lot of companies are going to end up buying 64-bit hardware such as servers anyway, for the simple reason that 32-bit hardware will be phased out. Microsoft's Jim Allchin, group vice-president for platforms, has said it will be difficult to buy a 32-bit server by the end of the year.

Unlike 32-bit computing, which introduced immediate and dramatic improvements, it seems likely that many organisations will end up with a 64-bit infrastructure and only afterwards begin to discover its benefits. "It's possible that everyone will have something they never use," says analyst James Governor of RedMonk. "Just look at Microsoft Office — people only use 5 percent of its functionality, but we all buy it."

That said, 64-bit computing can offer real benefits, and many analysts say it is now a mainstream reality. The wide availability of 64-bit capable chips that also support 32-bit applications, and now the launch of 64-bit Windows, mean that there are essentially no extra costs or complications associated with making the switch, at least on the hardware side. "The difference is that the hardware is cheap now. There is commodity pricing on servers, that is different," says Governor.

The time is now right for companies to begin looking into how their applications might be able to take advantage of 64-bit features, such as the ability to address exponentially more memory, according to research firm Gartner. "Enterprises must... begin preparing for the transition to the 64-bit platform," wrote Gartner's John Enck in a recent study.

What is it?
So what is all the fuss about, exactly? A 64-bit chip is one capable of handling chunks of data that are 64 bits wide. The number of locations in memory that a chip can address is determined by how wide these chunks of data are.

Thus 32-bit chips allow for 232 addresses, or 4GB of RAM; 64-bit chips and operating systems vastly increase this, depending on the implementation.Windows XP Professional x64 supports up to 128GB of RAM and 16TB of virtual memory, which could be increased in future versions of Windows. The AMD64 chip architecture can address up to 256TB of memory in its current implementations, though this could go up to 2 exabytes in future versions.

For several decades 4GB of RAM was plenty for most conceivable uses, but by the early 1990s 64-bit CPUs had begun to appear, mainly aimed at particular types of processing, such as video rendering and processing large databases, that benefited from the larger address space. In databases, for example, the ability to load the entire database into virtual memory can mean a huge performance boost. Intel's Itanium tried to target this market, but was hampered by being effectively incompatible with existing 32-bit software.

More recently AMD has pioneered the approach of selling 64-bit chips that include 32-bit addressing, meaning they run 32-bit applications at least as well as 32-bit-only chips. AMD calls its architecture AMD64, and uses it in the Opteron and Athlon 64 CPUs. Intel uses essentially the same architecture in newer chips, calling it EM64T. IBM sells 64-bit chips using the Power architecture, adapted for the PowerPC chips used in newer Apple computers (called G5 by Apple). What these all have in common is commodity pricing, with many ending up on inexpensive desktops.

On the software side, Unix has led the way, with 64-bit implementations appearing more than a decade ago. Linux has had 64-bit versions since 1994 (a port to the Alpha chip) and versions for the newer 64-bit architectures from AMD, Intel and IBM have been around for years. Mac OS X is a hybrid, with some recoding allowing the OS and applications to address more than 4GB of memory.

Real-world benefits
What can companies do with all this? Certain vertical industries have already been using 64-bit Unix — and increasingly Linux — for years, including the government and military, life sciences, manufacturing, research and development, energy and media businesses. For them the advent of commodity 64-bit chips and 64-bit Windows just lowers cost and provides more platform options to choose from.

Certain core Windows services should see big improvements in 64-bit Windows, including Windows Terminal Server (WTS), Internet Information Server (IIS) and Active Directory. The catch is that applications will need to be recoded from the ground up, even needing 64-bit drivers, in order to take advantage of the improvements. Microsoft is giving a number of its flagship products the 64-bit treatment this year, including SQL Server, Visual Studio 2005, Commerce Server 2006, Host Integration Server 2005, Biz Talk Server 2006 and Services for Unix; more are promised for next year as the company gears up for Longhorn.

All this recoding means it will take some time for the Windows ecosystem to become significantly 64-bit enabled. Microsoft admitted as much when it confirmed in April that Longhorn would come in 32-bit, 64-bit and Itanium versions, putting to rest speculation that the OS might be 64-bit only.

Still, companies who want to stay ahead of the curve should begin testing Windows Server x64 this year, Gartner says. The firm recommends testing 64-bit IIS and WTS deployments, to confirm their functionality and performance improvements; testing 32-bit applications on the 64-bit OS to make sure the drivers work and to see which packages could benefit from transitioning to 64-bit; and kicking the tyres on 64-bit applications and drivers.

As a demonstration, Microsoft has migrated Microsoft.com and the MSN Search and Messenger applications to Windows Server 2003 x64, claiming Messenger server performance has improved 10 times since the transition.

The advantages listed so far will apply to a relatively small core of companies willing to buy into specific, often niche 64-bit applications or perhaps recode the software themselves. More controversially, it is claimed that any company can run the same old 32-bit software on 64-bit Windows and see a significant performance improvement. IBM, for example, argues that customers can get immediate benefits from migrating to a 64-bit platform with 32-bit applications.

Some analysts dismiss such talk as nonsense, but it contains kernels of truth. One improvement with 64-bit Windows involves the way user programs are allowed to address memory. In 32-bit Windows, as in some other 32-bit operating systems, a portion of each process' address space is reserved for the use of the OS, which reduces the total amount of memory user programs can address. Under Windows XP, for example, each process can only address 2 or 3GB , even if 4GB of RAM is installed.

The limit is lifted under 64-bit Windows, so 32-bit programs that could benefit from addressing a full 4GB should show improvements. Critics say the need for a full 4GB of address space is currently still rare.

Increased complexity
For enterprises, the advent of 64-bit Windows and 64-bit extended chip architectures means, if nothing else, more choice and more complexity, says Gartner's Enck. At the simplest level, 64-bit-capable CPUs have become mainstream and many companies will begin to use them by default, if they are not already. The other options are to migrate to 64-bit Windows while sticking with 32-bit applications, or to use 64-bit Windows and some 64-bit applications.

Servers, workstations and PCs with Windows x64 pre-installed are becoming readily available, with systems already available or coming soon from vendors such as Acer, Alienware, Dell, FSC, Fujitsu, HP, Hitachi, IBM, NEC and Unisys. Some manufacturers, such as Dell and HP, also have upgrade programmes in place for customers with 64-bit capable hardware wanting to shift to 64-bit Windows without voiding their warranties.

The 64-bit operating system requires 64-bit drivers, even if all the applications are 32-bit. This could be a problem, at least for the near future; while many drivers are already out there, quite a few vendors haven't yet made drivers available.

Software with embedded device drivers will need to be recoded, and 16-bit applications don't work at all; these two types of software make up 20 percent of the applications currently running on Windows, according to Microsoft.

Microsoft is planning to maintain a directory of drivers and applications that have passed an x64 compatibility test, and promises to have the driver issue solved — for new hardware at least — by the time Longhorn appears. The biggest driver headache, though, could turn out to be caused by older devices — companies could well find that no 64-bit driver is forthcoming for, say, that three-year-old printer.

Applications
The current situation with applications is even more rarified — the applications simply aren't there. This will begin to change later this year with Microsoft and others gearing up application launches, but some key gaps remain.

For instance, most 32-bit desktop-level firewalls and antivirus products are incompatible with 64-bit Windows. Symantec, for one, says it doesn't currently support 64-bit Windows; the company says it is monitoring 64-bit adoption, and will eventually support the new operating system in its security products, but has given no timeline. McAfee offers limited enterprise support for 64-bit systems, but won't offer full support until sometime next year.

Some other applications present strange quirks. Microsoft decided to include both 32-bit and 64-bit versions of Internet Explorer in Windows x64, for the very good reason that 32-bit add-ons are incompatible with the 64-bit browser. That means the 64-bit IE can't handle Flash, Java or toolbars, and must launch PDF files in an external application.

The desktop
Server applications are likely to begin appearing before those aimed at the desktop, though workstations with 64-bit operating systems are expected to make up a significant proportion of shipments next year.

Outside of specialised workstations carrying out operations like video processing or financial simulations, there is currently little need for desktop applications to address large amounts of memory, say industry observers. While 1 GB is currently plenty for most workstations, requirements are likely to rise as desktops handle more digital content; 4GB DVD files are increasingly common on the desktop, for instance. Such requirements could mean a real need for the vast amounts of memory enabled by 64-bit software.

Microsoft says that once 64-bit hardware and operating systems become more widely used, developers will start to come up with ways of using all that power. Just think — searching could be 1,000 times faster if all your documents are stored in main memory instead of on a physical disk, Microsoft's Allchin told the Windows Hardware Engineering Conference.

This approach seems backward to some. "From a developer perspective, this is creating a market as opposed to responding to a market requirement," says RedMonk's Governor. "At the moment it's a technology in search of an application."