PowerPC - History

History

The history of RISC began with IBM's 801 research project, on which John Cocke was the lead developer, where he developed the concepts of RISC in 1975-78. 801-based microprocessors were used in a number of IBM embedded products, eventually becoming the 16-register ROMP processor used in the IBM RT. The RT was a rapid design implementing the RISC principles, and the performance was disappointing in comparison to the high performance 68000 microprocessor from Motorola. Between the years of 1982-1984 IBM started a project to build the fastest microprocessor on the market; this new 64-bit architecture became referred to as the "America Project" throughout its development cycle which lasted for approximately 5-6 years. The result was the POWER architecture, introduced with the RISC System/6000 in early 1990.

The original POWER microprocessor, one of the first superscalar RISC implementations, was a high performance, multi-chip design. IBM soon realized that a single-chip microprocessor was needed in order to scale its RS/6000 line from lower-end to high-end machines. Work on a one-chip POWER microprocessor, designated the RSC (RISC Single Chip) began. In early 1991, IBM realized its design could potentially become a high-volume microprocessor used across the industry.

IBM approached Apple with the goal of collaborating on the development of a family of single-chip microprocessors based on the POWER architecture. Soon after, Apple, being of Motorola's largest customers of desktop-class microprocessors, asked Motorola to join the discussions due of their long relationship, its more extensive experience with manufacturing high-volume microprocessors than IBM and to form a second source for the microprocessors. This three-way collaboration became known as AIM alliance, for Apple, IBM, Motorola.

In 1991, the PowerPC was just one facet of a larger alliance among these three companies. At the time, most of the personal computer industry was shipping systems based on the Intel 80386 and 80486 chips, which had a CISC architecture, and development of the Pentium processor was well underway. The PowerPC chip was one of several joint ventures involving the three, in their efforts to counter the growing Microsoft-Intel dominance of personal computing.

For Motorola, POWER looked like an unbelievable deal. It allowed them to sell a widely tested and powerful RISC CPU for little design cash on their own part. It also maintained ties with an important customer, Apple, and seemed to offer the possibility of adding IBM too, who might buy smaller versions from Motorola instead of making its own.

At this point Motorola already had its own RISC design in the form of the 88000 which was doing poorly in the market. Motorola was doing well with their 68000 family and the majority of the funding was focused on this. The 88000 effort was somewhat starved for resources.

However, the 88000 was already in production; Data General was shipping 88k machines and Apple already had 88k prototype machines running. The 88000 had also achieved a number of embedded design wins in telecom applications. If the new POWER one-chip version could be made bus-compatible at a hardware level with the 88000, that would allow both Apple and Motorola to bring machines to market far faster since they would not have to redesign their board architecture.

The result of these various requirements was the PowerPC (Performance Computing) specification.

When the first PowerPC products reached the market, they were met with enthusiasm. In addition to Apple, both IBM and the Motorola Computer Group offered systems built around the processors. Microsoft released Windows NT 3.51 for the architecture, which was used in Motorola's PowerPC servers, and Sun Microsystems offered a version of its Solaris OS. IBM ported its AIX Unix and planned a release of OS/2. Throughout the mid-1990s, PowerPC processors achieved benchmark test scores that matched or exceeded those of the fastest x86 CPUs.

Ultimately, demand for the new architecture on the desktop never truly materialized. Windows, OS/2 and Sun customers, faced with the lack of application software for the PowerPC, almost universally ignored the chip. The PowerPC versions of Solaris, OS/2, and Windows were discontinued after only a brief period on the market. Only on the Macintosh, due to Apple's persistence, did the PowerPC gain traction. To Apple, the performance of the PowerPC was a bright spot in the face of increased competition from Windows 95 and Windows NT-based PCs.

In parallel with the alliance between IBM and Motorola, both companies had development efforts underway internally. The PowerQUICC line was the result of this work inside Motorola. The 4xx series of embedded processors was underway inside IBM. The IBM embedded processor business grew to nearly 100 million in revenue and attracted hundreds of customers.

However, toward the close of the decade, the same manufacturing issues began plaguing the AIM alliance in much the same way it did Motorola, which consistently pushed back deployments of new processors for Apple and other vendors: first from Motorola in the 1990s with the G3 and G4 processors, and IBM with the 64-bit G5 processor in 2003. In 2004, Motorola exited the chip manufacturing business by spinning off its semiconductor business as an independent company called Freescale Semiconductor. Around the same time, IBM exited the 32-bit embedded processor market by selling its line of PowerPC products to Applied Micro Circuits Corporation (AMCC) and focused on 64-bit chip designs, while maintaining its commitment of PowerPC CPUs toward game machine makers such as Nintendo's GameCube and Wii, Sony's PlayStation 3 and Microsoft's Xbox 360 both use 64-bit processors. In 2005 Apple announced they would no longer use PowerPC processors in their Apple Macintosh computers, favoring Intel produced processors instead, citing the performance limitations of the chip for future personal computer hardware specifically related to heat generation and energy usage, as well as the inability of IBM to move the 970 (PowerPC G5) processor to the 3 GHz range. The IBM-Freescale alliance was replaced by an open standards body called Power.org. Power.org operates under the governance of the IEEE with IBM continuing to use and evolve the PowerPC processor on game consoles and Freescale Semiconductor focusing solely on embedded devices.

IBM continues to develop PowerPC microprocessor cores for use in their ASIC offerings. Many high volume applications embed PowerPC cores.

By July 2010, the POWER architecture IBM developed is still very much alive on their server offerings for large businesses and continues to evolve (and current POWER processors implement the full PowerPC instruction set architecture). For example, IBM's servers based on POWER have the highest revenue marketshare (53.9%) among UNIX servers.

The PowerPC specification is now handled by Power.org where IBM, Freescale, and AMCC are members. PowerPC, Cell and POWER processors are now jointly marketed as the Power Architecture. Power.org released a unified ISA, combining POWER and PowerPC ISAs into the new Power ISA v.2.03 specification and a new reference platform for servers called PAPR (Power Architecture Platform Reference).