Design Feature: September 2, 1996

The next 12 to 18 months hold the potential for major changes in the traditionally staid workstation business. The Intel Pentium Pro has caught up with the RISC µP architectures in integer performance. Meanwhile, application developers in several markets are eyeing the Windows NT OS, and the workstation vendors are striving to innovate at the system-architecture level to maintain a performance advantage. Today, workstation users should carefully evaluate their future hardware and software plans, and it's perfect timing for entrepreneurs to contemplate entering the workstation or add-on product market.

In contrast to the tempests that lie ahead, "stable" describes the workstation market over the past five years. The systems have evolved into faster units, although their architecture probably hasn't kept pace with increases in µP performance. Also, few changes have occurred in the market. The Director of Advanced Desktop Systems at research-company Dataquest, Andy Feit, says that Sun, Hewlett-Packard, IBM, Silicon Graphics, and Digital held the major market share during 1995 with 36, 20, 11, 9, and 7%, respectively. These percentages have been relatively consistent for several years and thus far into 1996.

To a large extent, the stability holds true within market segments as well. In the EDA market, Sun and HP dominate desktop applications. IBM has concentrated more on high-end computational servers than on single-user systems. Digital is increasing its EDA business on the Alpha platform after migrating from VAX- and MIPS-based systems.

Although it doesn't participate in the EDA market, Silicon Graphics targets and dominates the high-end mechanical, solids-modeling segment. The other workstation vendors are aggressively targeting this 3-D-intensive market, but Silicon Graphics leads by a considerable margin.

Despite the current stability, you can expect significant changes for several reasons. For one, the workstation vendors are aggressively seeking to boost market share by increasing µP and system performance. This fact may seem obvious, but it carries more significance that it has previously.

Historically, workstation vendors have dominated markets based on which application software ran on the system rather than strictly price/performance. Now, all of the RISC architectures have been around for some time. For the most part, manufacturers have ported key applications in the EDA, CAD, architecture, animation, and other segments to all of the leading workstation families.

The level playing field has allowed workstation vendors to compete based on price, performance, customer support, and other factors. And, make no mistake, it's critical for the workstation vendors to maximize market share now, because there's a new kid on the block. For the first time, an Intel architecture appears poised to gain a significant share of the workstation market. The Pentium Pro will offer users a cost structure more like that of that of the PC market and a performance rivaling the RISC architectures. More important than performance, however, the Pentium Pro also effectively runs big-league operating systems (OSs).

PCs vs workstations

Over the years, you've likely heard several discussions on how PCs and workstations differ. From the users' perspective, the only difference has surely always been software. Workstations run Unix, and PCs ran DOS and now run Windows. Moreover, virtually every application developer targets one environment or another.

The software distinction is extremely important. Software developers in areas such as EDA and mechanical CAD choose to develop for the workstation market, because the complex, mission-critical applications required a stable OS with features such as virtual memory, true multitasking, and memory protection. From a pure-hardware perspective, the fastest workstations have always been faster than the fastest PCs. Since the inception of the 386 µP, however, a high-end PC has been the hardware equal of the low-range to midrange workstations that most engineers use.

You can still best distinguish workstations and PCs by OSs and software. Today, however, Pentium- and Pentium Pro-based systems have the Windows NT OS, which offers a robust set of features. For typical desktop (single-user/single-CPU) computing, Windows NT offers most of the same features as Unix. The Intel processors can also effectively run Unix offerings from several vendors.

The Windows NT appeal

From a user's perspective, Windows NT offers undeniable benefits. For example, Intel-based systems running Windows NT can run all of the productivity applications PCs can run. Some Unix zealots may argue the point, but most workstation users would like access to PC applications. The workstation vendors themselves verify this fact by offering everything from x86-coprocessor cards to software interpreters that can host PC applications on a workstation.

In newer software segments, application developers have roundly endorsed Windows NT—often developing for Windows NT before Unix. Such segments include multimedia content creation, visualization, and animation.

In other entrenched segments, such as EDA, application vendors have been slow to embrace Windows NT. The vendors provide a flurry of reasons, but look past the smoke and mirrors and you will discover two primary reasons. First, the vendors are reluctant to make the substantial investment required to port to and support a new OS—especially before engineering desktops make wide use of Windows NT. Second, the vendors have always enjoyed relatively high selling prices and significantly higher profit margins than those in the PC world. The vendors fear that supporting Windows NT may force significant price cuts.

Ultimately, however, the software vendors have little choice about supporting Windows NT for several reasons. In EDA for instance, vendors that started selling low-end, PC-based tools are starting to impact the business of the high-end tool vendors. Entrepreneurs see Windows NT as an untapped market opportunity. Already, Intergraph Electronics offers its Veribest tools for NT, and Cadence Design Systems (San Jose, CA), Mentor Graphics (Wilsonville, OR), and Viewlogic (Marlborough, MA) are slowly making strides toward NT (Reference 1). Windows NT is probably a long way from hosting the tools used to simulate next-generation, 10 million-transistor processors, but it certainly will serve on the desktop. By 2000, it may even dominate on the desktop.

Vendors bet on Pentium Pro

Several workstation vendors have bet their future on the Pentium Pro. Intergraph was the first traditional workstation vendor to adopt the Intel architecture as a replacement for the Clipper line of systems. Today, Intergraph offers Pentium- and Pentium Pro-based systems that target mechanical CAD, visual simulation, multimedia, and EDA.

Intergraph's TD and TDZ families include systems based on the 200-MHz Pentium Pro and offer performance comparable to that of the leading RISC workstations. The company aims the TDZ at 3-D applications. It includes 128 Mbytes of memory, Intergraph's RealiZm Open-GL-based graphics card, a 1-Gbyte SCSI disk, and Ethernet. The TDZ costs $16,800. A comparably equipped R10000-based Silicon Graphics Solid Impact system costs approximately $35,000 and offers only around 30% better performance. An Intergraph TD machine suitable for EDA, and identical to the TDZ, except for a 2-D graphics card, costs much less than $10,000. Comparably performing Sun or HP systems sell for more than $15,000.

Netpower is another company that bet its future on the Pentium Pro and Windows NT. A former president of Mips Technologies (Mountain View, CA) founded Netpower, which started out as a manufacturer of MIPS-based Windows NT workstations. The company had completed the design of an R10000-based system but scrapped the design in February in favor of a Pentium Pro system using an Intel motherboard. The company's Calisto family primarily targets 3-D applications, supports an internally designed PCI-based 3-D graphics card, and ranges in price from $5295 to $18,995.

Digital is the only workstation vendor of the top five to fully endorse the Pentium Pro. The company offers both Alpha- and Pentium-Pro-based units in the Personal Workstation line. The Intel-based systems come with third-party graphics accelerators from companies such as AccelGraphics (San Jose, CA) and Matrox (Dorval, PQ, Canada).

Although HP hasn't roundly endorsed the Pentium Pro and Windows NT as a workstation platform, the company has made internal changes that confirm NT as a viable platform. The company recently restructured internally and placed both the PC and workstation business units under the same management. Moreover, the same sales force now sells Pentium and Pentium Pro systems and PA-RISC systems. And, you can order the Intel-based systems with Windows NT.

You can buy Pentium Pro-based systems from any number of other vendors—from mainstream PC suppliers to other small workstation houses. Approach the purchase differently from if you were buying a PC, however, because you will likely have to network a Pentium-Pro-based workstation to a Unix-based enterprise. Vendors such as Digital, HP, Intergraph, and Netpower provide both the software and support necessary to ensure a seamless connection to a Unix-based environment.

As software becomes a less distinguishing factor, the workstation vendors are trying even harder to distinguish their products from a hardware perspective. Accurately comparing workstations based strictly on performance, however, requires that you test the systems in an application. All of the major vendors have benchmarks or specs that purportedly prove the superiority of their systems.

Still, a consideration of µPs and, especially, of the system architectures illuminates developments in the workstation market. All of the RISC-system vendors develop their own µPs and can innovate at the chip and system levels. Vendors of Intel-based systems depend totally on Intel for µP enhancements and partially for system enhancements, because virtually all these vendors use Intel core logic along with a µP. Today, this approach is an advantage, because Intel has developed competitive products from a performance perspective, system vendors reduce development cost by depending on Intel, and the ICs promise lower cost due to Intel's volume-production capabilities.

One thing's for sure: Only slight differences in integer performance exist among Digital's Alpha, HP's PA-8000, IBM's Power2, Silicon Graphics' R10000, Sun's UltraSPARC, and the Pentium Pro. The RISC chips afford a significant advantage in floating-point performance relative to the Pentium Pro.

Some RISC vendors claim an advantage in their move to 64-bit architectures. Although HP's PA-RISC family has always featured an internal 64-bit architecture, the PA-8000 that HP announced this year is the company's first architecture to include a full 64-bit data/address bus. In the SPARC world, Sun's UltraSPARC and Hal's SPARC64 feature 64-bit architectures, although 32-bit implementations based on the Ross HyperSPARC still dominate in volume shipments. Digital's Alpha has been 64 bits since day one, and the MIPS R10000 is also a 64-bit architecture.

The need for 64 bits

Today, however, a 64-bit µP offers few compelling advantages. The importance of 64-bit systems lies in the maximum supported file and memory sizes, rather than in computational performance advantages. For example, you cannot simulate entire complex ICs on a 32-bit system, because the databases on these systems are simply too large. Instead, designers must break a large circuit into pieces for simulation.

Hardware is only half the story when it comes to 64-bit systems. Few OSs and virtually no commercial applications fully support 64-bit hardware. Digital offers 64-bit Unix for its systems, and Hal has licensed Sun Solaris and revamped the OS with a 64-bit kernel, but Sun doesn't offer a 64-bit OS. Hal recently announced the HALstation 353 based on the SPARC64 with an option for as much as 3 Gbytes of main memory. A Hal system with 1 Gbyte of RAM and a 4-Gbyte disk costs $106,695.

Even with a 64-bit OS, users can't take advantage of the larger address space without 64-bit applications. Commercial software vendors have yet to move to 64 bits, because they have to rewrite their applications to do so. And, software vendors probably won't budge until a significant part of the installed hardware base can take advantage of 64-bit software.

In a more likely short-term scenario, HP, Silicon Graphics, and Sun are cooperating to define the software interfaces necessary for 32-bit hardware to access a 64-bit address space. Such a specification could virtually eliminate the need for 64-bit hardware. The system vendors, however, are likely to continue to boast about 64-bit µPs simply as a marketing ploy. The 64-bit hype has succeeded in causing many large customers to include 64-bit hardware as a check-off requirement for new purchases.

Fast memory paths

Regardless of bus width, some system architectures provide a compelling performance boost. With ever-faster µPs, the most effective innovations are occurring in the path to main memory. DRAM has not kept pace with µP speeds, so designers must find innovative ways to speed data and instruction flow to the CPU.

Innovative cache designs offer one way to maximize the pipeline into the CPU. Hal, for example, packages its SPARC64 µP on a multichip module with a cache, memory-management unit (MMU), and I/O. Hal's level-2 cache employs a four-way, set-associative architecture, which is more efficient than the more common direct-mapped caches. This efficiency results from the system's ability to map main-memory locations with greater granularity than can direct-mapped caches (Figure 1). Hal claims that the design delivers a peak throughput of 944 Mbytes/sec between the µP and memory.

Sun takes a different approach with the UltraSPARC µP and Ultra 1 and 2 systems. The company has adopted the UltraSPARC Port Architecture (UPA) based on a buffered crossbar switch that connects the µP, memory, graphics, and I/O (Figure 2). UPA datapaths are 32 to 128 bits wide, include 1 bit per byte for ECC, and carry packetized data.

The UltraSPARC µP leverages a split-transaction memory-access scheme and speculative loading. These features allow it to issue multiple memory-access requests in a UPA system. Sun claims that the scheme delivers peak throughput of 1.3 Gbytes/sec between one or two processors and memory (Reference 2).

Other vendors of RISC systems also use crossbar memory switches, but none has revealed a packet-based architecture as robust as UPA. The Pentium Pro employs a packet-based, split-transaction bus to interface with memory, although the bus supports only eight active transactions for as many as four tightly coupled µPs. Sun's architecture doesn't limit the number of outstanding transactions, but the company claims that applications such as EDA benefit from six or more outstanding transactions per processor.

Multiprocessor designs

Robust processor buses also enable multiprocessor workstation designs. Intel's Pentium Pro and Mips' R10000 can both connect four µPs with little glue logic. Intergraph and others offer four-processor systems. HP also offers PA-8000-based systems with as many as four µPs. For now, Sun has announced only dual-processor UPA-based UltraSPARC-based systems. Other SPARC implementations, such as the Ross HyperSPARC, support four-processor implementations.

Multiprocessor systems offer limited benefits in the single-user workstation market. Developers in this market typically do not design applications to leverage parallel threads of execution. Both Unix and Windows NT, however, include multithreaded support. In some cases, a dual-processor system can offer a 40% performance advantage over single-processor systems, simply because the multithreaded OS executes more efficiently (Reference 2).

Competition, clones, and prices

For certain, users demand performance from workstations, but price/performance is even more important for most. Across the board, prices have declined relative to performance; in some cases, prices stay constant while performance increases dramatically. You can find the best price/performance ratio in competitive markets.

The Intel-based systems promise to offer the lowest prices and the most competition. Many competitors also exist in the Sun SPARC market. Today, you can buy Sun-compatible SPARC systems from Aries, Axil, Hal, Integrix, Ross, and Tatung. Hal targets the high end, and the others offer mainstream systems.

According to Feit of Dataquest, Sun-compatible vendors add about 5% to SPARC workstations' market share to Sun's 36%. The Sun-clone market, however, could grow more rapidly for several reasons. First, the clone vendors offer prices 10 to 20% lower than does Sun. Even more important to some customers, the clone vendors offer more flexible system configurations in terms of disk drives, monitors, and even the number of Sbus expansion slots.

Second, Ross Microcomputer has recently entered the system market. Ross Microcomputer's parent company, Ross Technology, has offered the HyperSPARC µP and core logic for years, and Ross has been a major supplier to Sun and the other Sun-compatible vendors. Ross Technology continues to push MBus technology to new speed heights, yet Sun has moved on to UPA. Now, Ross Microcomputer is offering boards and systems that complement the parent company's µPs and processor modules. OEMs can buy any combination of Ross Technology products to build competitive systems. Ross Microcomputer is even selling upgrade motherboards to owners of old SPARC systems.

PowerPC enters race

Another processor architecture that could impact price/performance is IBM's Power 2, a superset of the Power PC µP, which the company has long used in its RS-6000 systems. The company has focused mainly on work-group servers with the Power 2 architecture but, over the last year, has begun to push PowerPC-based single-user systems. IBM has the advantage of offering a software-compatible environment from portable PowerPC-based Thinkpad workstations to the RS-6000 line. The PowerPC-based models could offer a compelling price/performance ratio.

The IBM model points out perhaps the only verifiable trend in the workstation market—toward less expensive systems on each desktop with more work-group computation servers for applications such as simulation. The severs carry prices from $50,000 to more than $100,000 and are too costly for every desktop. On the other hand, servers with such power cost $1 million just five years ago. The drop allows companies to move the computational power closer to each desktop, thereby making the power more accessible. These servers allow companies to buy less expensive workstations. Vendors that base their workstations on Intel Pentiums can benefit from this trend. Digital, in fact, can leverage both its Intel and Alpha platforms to score wins in both markets.

References

1. Lipman, Jim, "Windows-based EDA tools: shifting into high gear," EDN, Feb 1, 1996, pg 42.
2. Wright, Maury, "New architectures lead the way," EDN, July 18, 1996, pg 36.