Editing PowerPC (section)

== History ==

The history of RISC began with IBM's [[IBM 801|801]] research project, on which [[John Cocke (computer scientist)|John Cocke]] was the lead developer, where he developed the concepts of [[Reduced instruction set computing|RISC]] in 1975–78. 801-based microprocessors were used in a number of IBM embedded products, eventually becoming the 16-register [[IBM ROMP]] processor used in the [[IBM RT PC]]. The RT PC was a rapid design implementing the RISC architecture. Between the years of 1982 and 1984, IBM started a project to build the fastest microprocessor on the market; this new [[32-bit]] architecture became referred to as the ''America Project'' throughout its development cycle, which lasted for approximately 5–6 years. The result is the [[IBM POWER Instruction Set Architecture|POWER instruction set architecture]], introduced with the [[RS/6000|RISC System/6000]] in early 1990.

The [[POWER1|original POWER microprocessor]], one of the first [[superscalar]] RISC implementations, is 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 began on a one-chip POWER microprocessor, designated the RSC ([[RISC Single Chip]]). In early 1991, IBM realized its design could potentially become a high-volume microprocessor used across the industry.

=== Apple and Motorola involvement ===
Apple had already realized the limitations and risks of its dependency upon a single CPU vendor at a time when Motorola was falling behind on delivering the [[Motorola 68040|68040]] CPU. Furthermore, Apple had conducted its own research and made an experimental quad-core CPU design called Aquarius,<ref name="Apple: The Inside Story"/>{{rp|86–90}} which convinced the company's technology leadership that the future of computing was in the RISC methodology.<ref name="Apple: The Inside Story"/>{{rp|287–288}} 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 one of Motorola's largest customers of desktop-class microprocessors,<ref>{{cite web | title = Tech Files Columns, 1987–1990 | url = http://www.joelwest.org/Press/TechFiles.html#01.03.89 | url-status = live | archive-url = https://web.archive.org/web/20130606044423/http://www.joelwest.org/Press/TechFiles.html#01.03.89 | archive-date = June 6, 2013 | df = mdy-all }}</ref> asked Motorola to join the discussions due to their long relationship, Motorola having had more extensive experience with manufacturing high-volume microprocessors than IBM, and to form a second source for the microprocessors. This three-way collaboration between Apple, IBM, and Motorola became known as the [[AIM alliance]].

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 have a [[complex instruction set computer]] (CISC) architecture, and development of the [[P5 (microarchitecture)|Pentium]] processor was well underway. The PowerPC chip was one of several joint ventures involving the three alliance members, in their efforts to counter the growing Microsoft-Intel dominance of personal computing.

For Motorola, POWER looked like an unbelievable deal. It allowed the company to sell a widely tested and powerful RISC CPU for little design cash on its own part. It also maintained ties with an important customer, Apple, and seemed to offer the possibility of adding IBM too, which 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 [[Motorola 88000|88000]], which was doing poorly in the market. Motorola was doing well with its [[Motorola 68000|68000]] family and the majority of the funding was focused on this. The 88000 effort was somewhat starved for resources.

The 88000 was already in production, however; [[Data General]] was shipping 88000 machines and Apple already had 88000 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 is the PowerPC (''performance computing'') specification. The differences between the earlier POWER instruction set and that of PowerPC is outlined in Appendix E of the manual for PowerPC ISA v.2.02.<ref name=powerpc_archguide />

=== Operating systems ===
Since 1991, IBM had a long-standing desire for a unifying operating system that would simultaneously host all existing operating systems as personalities upon one microkernel. From 1991 to 1995, the company designed and aggressively evangelized what would become [[Workplace OS]], primarily targeting PowerPC.<ref name="Apple: The Inside Story">{{cite book | title=Apple: The Inside Story of Intrigue, Egomania and Business Blunders | first=Jim | last=Carlton | orig-year=1997 | date=1999 | publisher=Random House | isbn=978-0099270737 | oclc=925000937 | url=https://archive.org/details/appleinsidestory0000carl | url-access=registration}}</ref>{{rp|290–291}}

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 (operating system)|Solaris]] OS. IBM ported its [[IBM AIX|AIX]] [[Unix]]. Workplace OS featured a new port of [[OS/2]] (with Intel emulation for application compatibility), pending a successful launch of the PowerPC 620. Throughout the mid-1990s, PowerPC processors achieved [[Benchmark (computing)|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. IBM's Workplace OS platform (and thus, OS/2 for PowerPC) was summarily canceled upon its first developers' release in December 1995 due to the simultaneous buggy launch of the PowerPC 620. The PowerPC versions of Solaris 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.

With the cancellation of Workplace OS, the general PowerPC platform (especially AIM's [[Common Hardware Reference Platform]]) was instead seen as a hardware-only compromise to run many operating systems one at a time upon a single unifying vendor-neutral hardware platform.<ref name="Apple: The Inside Story"/>{{rp|287–288}}

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 US$100 million in revenue and attracted hundreds of customers.

{{Blockquote|text=The development of the PowerPC is centered at an Austin, Texas, facility called the Somerset Design Center. The building is named after the site in Arthurian legend where warring forces put aside their swords, and members of the three teams that staff the building say the spirit that inspired the name has been a key factor in the project's success thus far.|source=''MacWeek''<ref name="MacWeek Vol7 Num12">{{cite magazine | magazine=[[MacWeek]] | title=Forces Gather for PowerPC Roundtable | volume=7 | issue=12 | date=March 22, 1993 | url=https://archive.org/details/MacWEEKV07N12/page/n37/mode/1up | page=38| access-date=October 3, 2017}}</ref>}}

{{Quote|text=Part of the culture here is not to have an IBM or Motorola or Apple culture, but to have our own.|source=Motorola's Russell Stanphill, codirector of Somerset<ref name="MacWeek Vol7 Num12"/>}}

=== Breakup of AIM ===
[[File:PowerISA-evolution.svg|thumb|A schematic showing the evolution of the different [[IBM POWER Instruction Set Architecture|POWER]], PowerPC and [[Power ISA|Power]] [[Instruction set architecture|ISAs]]]]

Toward the close of the decade, manufacturing issues began plaguing the AIM alliance in much the same way they did Motorola, which consistently pushed back deployments of new processors for Apple and other vendors: first from Motorola in the 1990s with the PowerPC 7xx and 74xx processors, and IBM with the 64-bit PowerPC 970 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 focusing on 64-bit chip designs, while maintaining its commitment of PowerPC CPUs toward game console makers such as [[Nintendo]]'s [[GameCube]], [[Wii]] and [[Wii U]], [[Sony Interactive Entertainment|Sony]]'s [[PlayStation 3]] and [[Microsoft]]'s [[Xbox 360]], of which the latter two 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 processor to the 3&nbsp;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 [[application-specific integrated circuit]] (ASIC) offerings. Many high volume applications embed PowerPC cores.

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).

=== Generations ===
Many PowerPC designs are named and labeled by their apparent technology generation. That began with the "G3", which was an internal project name inside [[AIM alliance|AIM]] for the development of what would become the [[PowerPC 7xx|PowerPC 750 family]].<ref>{{cite journal
 |url          = https://ieeexplore.ieee.org/document/584742
 |title        = A G3 PowerPC superscalar low-power microprocessor
 |doi          = 10.1109/CMPCON.1997.584742
 |publisher    = IEEE
 |journal      = Proceedings IEEE COMPCON 97. Digest of Papers
 |date         = 23 February 1997
 |author1      = A. R. Kennedy
 |author2      = M. Alexander
 |author3      = E. Fiene
 |author4      = J. Lyon
 |author5      = B. Kuttanna
 |author6      = R. Patel
 |author7      = M. Pham
 |author8      = M. Putrino
 |author9      = C. Croxton
 |author10     = S. Litch
 |author11     = B. Burgess
 |pages        = 315–324
 |s2cid        = 24733198
 |url-access   = subscription
 |access-date  = September 1, 2021
 |archive-date = September 1, 2021
 |archive-url  = https://web.archive.org/web/20210901203418/https://ieeexplore.ieee.org/document/584742
 |url-status   = live
}}</ref> Apple popularized the term "G3" when they introduced [[Power Macintosh G3 beige|Power Mac G3]] and [[PowerBook G3]] at an event at 10 November 1997. Motorola and Apple liked the moniker and used the term "G4" for the 7400 family introduced in 1998<ref>{{cite journal| url=http://www.eecg.toronto.edu/~moshovos/ACA07/lecturenotes/ppcg4%2520(mpr).pdf |title=G4 Is First PowerPC with AltiVec - Due Mid-1999, Motorola's Next Chip Aims at Macintosh, Networking |archive-url=https://web.archive.org/web/20160423044536/http://www.eecg.toronto.edu/~moshovos/ACA07/lecturenotes/ppcg4%2520(mpr).pdf |archive-date=April 23, 2016 |url-status=live |first=Linley |last=Gwennap |date=16 November 1998 |journal=[[Microprocessor Report]]}}</ref><ref>{{cite web |url=https://www.nxp.com/docs/en/white-paper/G4WP.pdf |title=PowerPC G4 Architecture White Paper |archive-url=https://web.archive.org/web/20160418222351/http://www.nxp.com/files/product/doc/G4WP.pdf |archive-date=April 18, 2016 |url-status=live |website=[[NXP Semiconductors]] |first = Susan | last = Seale | date = 2001}}</ref> and the [[Power Mac G4]] in 1999.

At the time the G4 was launched, Motorola categorized all their PowerPC models (former, current and future) according to what generation they adhered to, even renaming the older 603e core "G2". Motorola had a [[Motorola G5 project|G5 project]] that never came to fruition, and Apple later used the name when the [[PowerPC 970|970 family]] launched in 2003, though it was designed and built by IBM.

;PowerPC generations according to Motorola, c. 2000.<ref>{{cite web |url=https://www.nxp.com/docs/en/fact-sheet/PPCCPUINTFACT.pdf |title=Fact Sheet - Motorola PowerPC Processor | url-status=live |archive-url=https://web.archive.org/web/20160419012406/http://www.nxp.com/files/32bit/doc/fact_sheet/PPCCPUINTFACT.pdf |archive-date=April 19, 2016 |website=[[NXP Semiconductors]]}}</ref>
:G1: The [[PowerPC 600#PowerPC 601|601]], [[MPC5xx|500]] and [[PowerQUICC#PowerQUICC I|800]] family processors
:G2: The [[PowerPC 600#PowerPC 602|602]], [[PowerPC 600#PowerPC 603|603]], [[PowerPC 600#PowerPC 604|604]], [[PowerPC 600#PowerPC 620|620]], [[PowerQUICC#PowerQUICC II|8200]] and [[PowerPC 5000|5000]] families
:G3: The [[PowerPC 7xx|750]] and [[PowerQUICC#PowerQUICC II Pro|8300]] families
:G4: The [[PowerPC G4|7400]] and 8400* families
:G5: The [[Motorola G5 project|7500]]* and [[PowerQUICC#PowerQUICC III|8500]] families (Motorola abandoned the G5 name after Apple applied it to the 970)
:G6: The [[PowerPC e700|7600]]*
:''(*) These designs didn't become real products.''