Intel's Itanium on Launch Pad

by Linley Gwennap

After more than six years of effort, Intel is finally ready to deploy its first processor based on the IA-64 instruction set, which it co-developed with Hewlett-Packard. The chip, named Itanium, is designed to go where no Pentium has gone before: the high end of the server market. When it arrives, Itanium will open doors not just for Intel but also for Linux. Today, a few large companies ship the vast majority of big servers. Sun, HP, IBM and Compaq servers rely mainly on proprietary RISC processors and proprietary versions of UNIX. But with the turbo-charged Itanium, many other vendors will deliver servers that match the power of these proprietary machines. These vendors are likely to rely on Linux or one of two key competitors: Monterey UNIX or Windows 2000.

Itanium Designed for Servers

Intel is no stranger to the server market. Its chips have been used in PC servers for years, and in 1998, the company introduced the Xeon product line specifically for bigger systems. But there is little to distinguish the latest Xeon products from the Pentium III chips in PCs: they use the same CPU, have the same bus bandwidth and remain limited to 32-bit virtual addressing. Itanium is Intel's first CPU designed from the ground up for server applications. For starters, the chip offers 64-bit addressing, providing programmers with much more flexibility when dealing with large objects and data sets. RISC processors have included 64-bit addressing for nearly a decade.

Instead of simply extending the aging x86 instruction set to 64 bits, Intel decided to leap to a new instruction set, IA-64. This state-of-the-art design includes a host of performance-enhancing features—such as predication, speculation and register frames—that are not found in x86 or RISC processors.

The general intent of these features is to give the compiler more control over the hardware. In theory, the compiler can make better decisions about how to group and order instructions for optimal performance. Furthermore, the processor hardware is simplified by relying on the compiler to make these decisions. Simpler processors can be both faster and less expensive to manufacture. Many previous instruction sets have failed to gain significant market share. The problem has been incompatibility with existing software. Itanium solves this problem by including an x86 translation unit on the chip. This unit can process any existing x86 application, albeit at a lower speed than an application that has been recompiled for IA-64.

Itanium Systems Nearly Ready

Intel has already produced hundreds of Itanium prototypes that are being used to validate new IA-64 hardware and software. Although there may be a few glitches remaining, the project appears on track. More than two dozen vendors plan to deploy Itanium systems, with the first systems appearing this fall.

In fact, nearly every major server vendor except Sun Microsystems has endorsed IA-64. Over time, HP will convert its entire line of RISC systems to the new architecture, as will SGI. IBM and Compaq will continue to develop RISC processors and systems, but will also deploy a broad range of IA-64 products. Companies such as Acer, Dell and Gateway will add Itanium to their Xeon server lines. With all of this backing, IA-64 is likely to grab at least 60% of the server market by 2003, according to a new report “Intel's Itanium and IA-64” from MicroDesign Resources. This would represent a big change from today's market, which is split among a variety of platforms. Linux holds 25% of the server market, according to IDC, a number that is rising rapidly. Although Linux is offered on several RISC platforms, the makers of these systems prefer to sell their own proprietary UNIX versions. Linux has been most popular on x86 systems from PC server makers. These vendors are most likely to benefit from Itanium. Current Intel processors can't match the performance and bandwidth of the best RISC systems, limiting PC server makers to low-end and mid-range systems. Using Itanium and Intel's new Lion motherboard, PC server makers will push into high-end markets, taking Linux with them.

Linux Competitors Join Forces

Linux faces strong competitors in the Itanium market. IBM and SCO are merging their versions of UNIX, AIX and UnixWare into an IA-64 operating system known as Monterey. Based on the AIX kernel, Monterey offers reliability and scalability features from IBM's high-end servers. Because of the popularity of UnixWare, Monterey is a natural choice for Itanium systems from Compaq, Dell and, of course, IBM. Microsoft hopes to dominate the IA-64 market with a 64-bit version of its Windows 2000 operating system. Most PC server vendors will offer this as the default choice for Itanium systems. Previous Microsoft server products lack robustness and do not scale well beyond four processors; the company is working to fix these problems, but how long this will take remains to be seen. For small and mid-range servers, however, Windows will no doubt be a popular choice.

Linux's open-source model provides an advantage over these competitors, and it continues to gain features that will help it better compete against the likes of Monterey. As IA-64 processors displace proprietary RISCs from the high-end market, they create opportunities for newer operating systems. This platform change should boost Linux's prospects.

Linley Gwennap ( is the founder and principal analyst of The Linley Group (, a technology analysis firm in Mt. View, California, and the author of the report “Intel's Itanium and IA-64”.
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