Under the Hood of Advanced Server Limited Edition

Microsoft Corp. unveiled a new version 1.2 release of its Windows 2000 Advanced Server Limited Edition (ASLE) operating system last month. The software giant says that ASLE 1.2 is designed to take advantage of some of the performance improvements – including a higher clock-speed and an improved bus architecture – boasted by Intel Corp.’s Itanium 2 microprocessor.

ASLE 1.2 may benefit just as much from the efforts of two prominent vendors – Hewlett-Packard Co. (HP) and Unisys Corp. – which have developed unique system architectures to support mixed IA-64, IA-32 and (in the case of HP) PA-RISC environments.

First, the basics. ASLE 1.2 is the second rev of Microsoft’s 64-bit server operating system. ASLE 1.0, Microsoft’s first foray into 64-bit computing, shipped in August 2001, and was followed in October by a 64-bit version of the software giant’s Windows XP Professional operating system. Sixty-four-bit ASLE is generally positioned for large database or compute-intensive environments; 64-bit Windows XP Professional is marketed as a Windows platform for high-performance workstations.

According to Velle Kolde, lead product manager in the Windows .NET Server group, ASLE 1.2 – which is based on the forthcoming Windows .NET Server code-base – is optimized to take advantage of a variety of Itanium 2-specific capabilities. “We’ve actually gone in and optimized the kernel to take advantage of the Itanium 2 chips, so the Microsoft system compiler takes advantage of all of the Itanium 2 features, [such as] parallel execution, speculative data loads, cache pre-caching, register locations, software pipe-lining.”

Kolde acknowledges that some of these features were implemented in Itanium 1, but says that ASLE 1.0 wasn’t optimized to take advantage of them. Besides, he argues, the higher clockspeeds and improved performance of Itanium 2 give ASLE 1.2 a real shot in the arm: “The entire system is compiled for these optimizations, a lot of which were not present, or were not optimized, in the earlier versions [Itanium 1 and ASLE 1.0].”

To further sweeten the value proposition, Kolde says that customers who purchase ASLE 1.2 will be entitled to a free upgrade to 64-bit Windows .NET Server when it ships later this year.

Growing Pains

Even the most optimistic of Itanium supporters acknowledges that Itanium v1.0 was more of a proof-of-concept than anything else.

“The product was very late. So by the time it hit the streets, it was definitely not awesome. It was, depending on how you measure, anywhere from two years to four years late,” says Nathan Brookwood, an analyst with microprocessor consultancy InSight64. “You almost have to look at the Merced-based Itanium platform as a proof of concept and software development vehicle much more so than any sort of practical vehicle.”

Not surprisingly, Itanium 1 uptick was less than phenomenal.

Itanium 2, on the other hand, is almost unequivocally regarded as the real deal. According to InSight64’s Brookwood, Itanium is faster than any of the 64-bit RISC processors that power top-of-the-line high-end servers from IBM Corp., HP and Sun Microsystems Inc.

“Itanium is faster than the IBM Power 4, it’s faster than HP PA-RISC, it’s dramatically faster than SPARC, It’s faster than Alpha,” he says. “On processor benchmarks, in particular, the SPEC benchmarks, Itanium 2 running on HP workstations and servers set a new record. So it is faster than any other 64-bit processor on the SPEC list.”

As a result, vendors and analysts alike expect to see customers deploy Itanium 2-based systems in production environments. Microsoft’s Kolde, for example, anticipates that ALSE 1.2 uptick could take place in data-intensive applications – such as data-warehousing and large, in-memory databases – and in compute-intensive applications, especially encryption.

“The end user license that comes with ASLE [1.2] is a full production license, and customers receive full support from both the vendor and Microsoft, including QFEs and hotfixes,” Kolde asserts.

Achilles Heel

Like its predecessor, however, Itanium 2 suffers from a single, perhaps catastrophic shortcoming: It must run 32-bit (IA-32) software in emulation mode, which – depending on the application – can result in a significant performance hit. While a situation of this kind isn’t necessarily a problem on a platform such as, for example, HP-UX – which, after all, has been ported over from HP’s 64-bit PA-RISC architecture – it amounts to nothing less than an Achilles heel in Windows environments, which are powered almost exclusively by 32-bit applications designed for IA-32.

“There are some faster 32-bit processors, in particular Intel Pentium IV Xeons running at 2.5 GHz,” allows InSight64’s Brookwood. “Consequently, Intel’s 32-bit servers are still a little faster on SPEC than Itanium 2.”

As a result, concedes Microsoft’s Kolde, customers who adopt ASLE 1.2 must be judicious about the applications that they choose to deploy on it.

“If a customer wants to run a native 32-bit application [on ASLE 1.2], they’re going to get the best price-performance by running it on a 32-bit server. The way you’re really going to get the benefit of a 64-bit Itanium server is to buy native Itanium applications,” he says. “Running 32-bit apps on 64-bit, it depends on the precise applications, on how it is running. But if it is running in an emulation layer it probably won’t be as quick as running it natively.”

To date, however, Microsoft still hasn’t managed to ship an official release version of a 64-bit application, its 64-bit ASLE and Windows XP Professional operating systems notwithstanding. Currently, a 64-bit version of the software giant’s SQL Server 2000 database – code-named “Liberty” – is still in the works. If Microsoft’s Kolde is correct, Liberty should ship along with 64-bit Windows .NET Server, which is slated to debut in lock-step with the IA-32 version of Windows .NET Server at the end of this year. Moreover, Microsoft hasn’t announced plans to develop 64-bit versions of its other .NET family applications. The upshot of it all is that – while organizations can deploy a pre-release version of Liberty right now – they’re almost certainly going to have to run 32-bit applications on Itanium 2, as well.

Because it’s newer and economies-of-scale haven’t yet come into play, however, your garden-variety IA-64 server is a lot more expensive proposition than its IA-32 equivalent. As a result, says Robert Dorin, a research director with consultancy Aberdeen Group ( ), unless an organization maintains or plans to develop an application that requires a 64-bit memory space, IA-32 remains the better value proposition, with superior performance and application compatibility, to boot.

A compelling alternative?

Not so fast, says Unisys VP of enterprise systems Mark Feverston – there’s another option. “We offer both IA-32 and IA-64 support in the ES7000,” he says, referring to Unisys’ high-end ES7000 16- and 32-way enterprise server. “In fact, we can offer both architectures in the same platform.”

Customers can configure the ES7000 with a mix of IA-32 and IA-64 processors. Because of the ES7000’s advanced workload-partitioning capabilities, it can be subdivided into many logical partitions – similar to mainframe LPARs – that each hosts an instance of an operating system. In this respect, Feverston notes, it’s possible to deploy a mix of 64- and 32-bit operating systems and applications on the same hardware. Not surprisingly, he continues, an approach of this kind makes a lot of sense as a strategy for server consolidation. But its real value could occur as a solution for mixed IA-64 and IA-32 development efforts.

“We also think that it’s going to be a very strong development platform in the IA-64 place. People say ‘I can’t go cold turkey to IA-64,’ so they partition an operating environment off, which allows them the luxury of having IA-32 partitions running the application, and the IA-64 partition running the database.”

This also gives an IT organization the leeway to move to IA-64 incrementally. “If there’s a cost benefit value to migrating to IA-64, then you do it. You can replace IA-32 and come back with Itanium,” Feverston says.

Unisys is currently the only vendor that offers the ability to mix-and-match IA-64 and IA-32 hardware. But HP, which has been an aggressive proponent of IA-64 since its inception, will eventually ship servers that boast similar capabilities, albeit with dissimilar architectures. In 16 months, says InSight64’s Brookwood, HP will debut a new version of PA-RISC that should enable customers to mix and match PA-RISC and Itanium 2 processors in the same server. The result, Brookwood argues, is that HP’s heterogeneous servers will be well-suited as platforms for server consolidation and as gateways for incremental IA-64 adoption. The goal, Brookwood allows, is to transition customers off of PA-RISC.

“If you are a customer and you need to transition to IA-64, HP has made it about as painless as anybody could,” he says.

About the Author

Stephen Swoyer is a Nashville, TN-based freelance journalist who writes about technology.


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