NT's greatest RISC
While the world waits for Intel's 64-bit Merced chip and Microsoft's 64-bit version of Windows NT, Digital Equipment is offering a sneak preview of the next generation in NT processing. The Alpha 21264 is a 64-bit processor that runs NT. It's one of the fastest chips in the world. And it's available today.
The 21264 is the latest generation of the Alpha microprocessor architecture. Digital expects the 21264 to reach clock speeds of more than 700MHz this year, so this processor upholds the speed demon reputation that the 21164 and 21064 established for Alpha chips.
Alpha is the last RISC architecture for which Microsoft is developing future versions of NT. Microsoft is phasing out NT for MIPS Rx000 chips, and the PowerPC NT never really got off the ground. The only other CPU architecture that runs NT is, of course, Intel x86. Despite Intel's market dominance, the Alpha has one big advantage over the x86: increased performance, especially performance of floating-point tasks. Alpha systems generally cost more than their Intel counterparts, but Alpha systems are faster, and they excel at math-intensive engineering and scientific applications.
To move beyond the performance limitations of the 20-year-old x86, Intel partnered with HP in 1994 to develop a new CPU architecture: Intel Architecture-64 (IA-64). Intel expects systems that use the Merced processor, the first processor to implement IA-64, to ship in mid-2000. But the Merced might not be the fastest chip on the NT market in 2000. Digital says that by the time Merced appears, the 21264 will be running at a clock frequency of 1000MHz (1 gigahertzGHz). At that speed, the 21264 will be substantially faster than the Merced according to estimated CPU benchmarks. (For a review of 21264 speeds, see Graph 1, page 162.)
Digital said the first 21264 systems would hit the streets in late 1998, so you don't have to wait 2 years for 64-bitperformance. However, the 21264 won't reach its potential until Microsoft ships a 64-bit version of NT for both IA-64 and Alpha chips. (Microsoft hopes to ship the 64-bit NT in 2000.)
Whither RISC?
The race between the 21264 and IA-64 processors is not just a subject of idle gossip. At stake is nothing less than the future of RISCfor NT and every other operating system (OS).
Outside of the highly specialized embedded-application market, RISC is in retreat. Currently, the most popular RISC architecture for the desktop is the PowerPC chip, which IBM and Motorola produce jointly. But the largest customer for desktop PowerPC chips is Apple, and the Macintosh has only about 4 percent of the PC market share according to International Data Corporation (IDC). In June, IBM and Motorola announced that they are dissolving their 7-year PowerPC partnership and will develop future PowerPC chips separately.
IBM's other RISC architecture, the Power series, is merging with the PowerPC. IBM is phasing out the Power chip as a distinct architecture. The new 64-bit Power3 chip is the first processor that unifies Power and PowerPC technologies.
Battling recent losses, Silicon Graphics is moving away from its MIPS Rx000-series RISC processors. Silicon Graphics canceled its next-generation Rx000 projects and recently spun off the embedded-chip portion of MIPS Technologies as a separate company. Silicon Graphics is developing x86-based systems for NT and porting IRIX to IA-64.
Sun Microsystems is porting Solaris to IA-64. That move has prompted some industry analysts to speculate that the new UltraSPARC-III will be the last major generation of the SPARC family, although Sun claims that the rumors are false.
HP is porting HP-UX to IA-64 as part of its strategy to move away from Precision Architecture-RISC. PA-RISC will gradually exit the market after IA-64 debuts. IA-64 will be backward compatible with PA-RISC.
The Alpha is the fastest RISC chip according to most CPU benchmarks and the only NT alternative to the x86. But the Alpha's future isn't certain because of recent shakeups at Digital. The company sold its chip foundry in Hudson, Massachusetts, to Intel. Despite some misleading news reports, Digital sold only the foundry, not the Alpha. Digital will continue to independently design Alpha processors but will farm out the chips' manufacturing to Intel and other licensees. The two current Alpha-manufacturing licensees are Samsung and Mitsubishi. Digital is also negotiating deals with AMD and IBM Microelectronics. Mitsubishi currently has no plans to manufacture the 21264, although the company continues to provide technical support for the low-cost 21164PC chips it manufactured. Samsung has emerged as the most aggressive Alpha licensee. It recently formed a subsidiary to market Alpha chips and says it will push the 21264 to 1GHz by 2000.
Compaq's acquisition of Digital makes the Alpha's fate more uncertain. Compaq has never owned a CPU architecture, and the company is one of Intel's largest customers for x86 chips. David Jessel, the Alpha's senior product manager, claims that Alpha fans have nothing to worry about. "Compaq has been fully supportive of the Alpha and is continuing to invest in it," Jessel said. To underscore its commitment to the Alpha, Compaq plans to substitute the 21264 for MIPS processors in its high-end Tandem servers.
If the Alpha survives all these transitions, it could seriously challenge IA-64 chips for performance supremacy in the next decade. A technical analysis of the 21264 shows that the Alpha has plenty of room to become more powerful.
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