Apple, IBM Team on 64-Bit CPU

 
 
By Matthew Rothenberg  |  Posted 2002-09-19
 
 
 

Apple, IBM Team on 64-Bit CPU


Apple Computer is looking toward a 64-bit future for the Mac -- courtesy of PowerPC partner IBM.

According to sources, IBM Microelectronics, a division of IBM, is working with Apple on a 64-bit PowerPC processor for use in the latters high-end desktops and servers.

Sources said Apple is testing the CPU, dubbed the GigaProcessor Ultralite (GPUL) on Mac OS X-based hardware at its Cupertino, Calif., headquarters, and making sure that the processor complies with a new bus architecture on tap for future Macs.

In addition, IBM plans to offer the processor as the centerpiece of future Linux-based systems, the sources said. As reported this week by eWEEK, IBM recently announced that it would soon introduce new versions of its high-end p690 and p670 servers designed to run Linux native, in place of IBMs own AIX operating system.

Some GPUL details are expected to be disclosed at Microprocessor Forum in San Jose, Calif., in mid-October. IBM will hold a session at the conference on Oct. 15 entitled "Breaking Through Compute Intensive Barriers -- IBMs New 64-bit PowerPC Microprocessor."

Peter Glaskowsky, editor in chief of forum sponsor Microprocessor Report, said that while he doubted GPULs role in the Macs future will be on the public agenda, "We expect this chip to form the basis of Apples 64-bit future strategy."

Some observers say GPUL—which shares technology with IBMs server-focused Power4 chip—will double Mac performance. However, they caution that the chip probably wont reach Apples systems for more than a year at the earliest.

While the bulky, power-hungry Power4 is designed for servers, GPUL is reportedly cooler and more compact; sources said it compares in size to Intels Celeron.

However, sources said, GPUL will inherit many Power4 performance advantages, such as being able to perform more instructions per clock cycle than current PowerPC chips. It is likely to also use the 0.13- (later 0.10-) µm lithography copper and silicon-on-insulator (SOI) technology seen in the Power4, making for smaller and thinner chips.

In addition, GPUL will be a multi-core chip, with two or four processors in one package. Having the processors closer together and sharing the same cache will make for faster multiprocessing environments, sources said. However, sources did not say if applications would need to be rewritten to be optimized for multi-core processors.

Sources said that benchmarks and applications tests demonstrate that a 1GHz GPUL processor doubles the performance of the 1GHz Motorola PowerPC G4 processor in current Macs. Even so, they said, the first run on GPUL processors should range from 1.4 to 2GHz, depending on yield.

GPUL will also support Vector/SIMD Multimedia Extensions (VMX), a group of 162 instructions that speed data processing and algorithmic-intensive tasks, such as multimedia creation and display.

Sources note that internal documents and publicly released information make no explicit mention of Motorolas Altivec multimedia extensions currently used in the PowerPC G4 and marketed under the name Velocity Engine by Apple. However, they said that VMX and Altivec are highly compatible, if not identical.

GPUL


: Focus on Mac OS X">

GPUL: Focus on Mac OS X

While GPUL is also designed to support eight-processor systems running the AIX OS, sources said Apple is focusing on testing the chip on dual-processor, Mac OS X-based systems. Apple and IBM are also tailoring the chip for a new high-frequency, point-to-point Mac bus dubbed ApplePI, short for Apple Processor Interconnect. According to sources, the companies describe ApplePI as "a replacement for the MaxBus used on current Apple systems. ApplePI is used to connect high-performance PowerPC processors to memory and high-speed I/O devices."

GPUL will also apparently play a role in IBMs desktop-Linux efforts. The Mac-focused Architosh site recently reported that Linux developer Red Hat, for one, may be working with IBM on a 64-bit, Altivec-compatible distribution. eWEEKs sources confirmed that GPUL is intended for Linux systems as well as the Mac.

Perhaps the most disappointing news for Mac fans, sources said, is that IBM does not expect to be finished with GPUL project until late summer 2003. Apples recent confirmation that new Macs released after January 2003 will boot in Mac OS X only had sparked speculation that the company was planning to unveil 64-bit Mac systems at Macworld Expo/San Francisco that month.

Like AMDs 64-bit Clawhammer (the release of which was recently delayed), GPUL processor is backward-compatible with 32-bit OSes and applications. One source said 32-bit Mac applications could run on GPUL with "a very small performance difference," although recompiled programs, as well as a recompiled OS, would be able to take advantage of new addressing modes as well as other 64-bit features.

Sources said this transition should be less complicated than Apples early-90s move from 68000-series Motorola processors to the PowerPC family founded by Apple, IBM and Motorola.

Development of a new processor line has become increasingly urgent for Apple. Even as its desktop offerings, powered by Motorola PowerPC G4 chips, have stalled near the 1GHz mark, Windows-based PCs sport CPUs from Intel and AMD that approach 3GHz.

Although many metrics minimize the link between simple clock speeds and real-world performance between radically different CPU architectures and OSes, the slow advance of Motorolas chips has apparently depressed Apples Mac sales.

However, sources said, Motorola probably will continue to play a role in Mac hardware. One observer familiar with Apples processor strategy said that even if Apple wanted to abandon Motorola chips, it wouldnt happen in less than three or four years -- at least when it comes to laptop-friendly chips such as the PowerPC G4 and the IBM-developed PowerPC G3, which still powers Apples consumer-level iBook notebook.

Meanwhile, sources said, the long-awaited PowerPC G5 CPU from Motorola is likely to break cover perhaps as soon as early 2003. The G5, according to published product road maps from Motorola, should be available as 32- and 64-bit products with backward compatibility, though Motorola has provided few additional details.

Official at Apple and IBM declined to comment.

Mac veteran Matthew Rothenberg is online editor for Ziff Davis Medias Baseline and CIO Insight magazines.

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